# Home Amp vs Pro Amp - Emotiva XPR-5 vs Behringer EP2500



## Sonnie

There has been quite a bit of discussion over the years about whether there is any difference in the sound of amps. It seems that opinions are pretty much split down the middle. My opinion is that most competent amps are going to sound very much alike on most of the average speakers out there. I will not argue that all amps can efficiently power all speakers, especially some of the more difficult speakers out there that dip on down to very low impedance of 1-2 ohms and/or those that may be inefficient (around 85dB). I agree those speaker may very well need beefier and more powerful amps. However, for the majority of the dynamic speakers out there that are 90dB and above, I firmly believe most 75+ wpc amps built today are going to drive them to sound the same at moderate to loud levels. If they sound different, then something is likely wrong with one or the other amp... or the amp is not designed to be neutral. Again... this is all my opinion, although there have been quite a few double blind tests conducted that prove the same. I personally will not accept that there is a difference unless it can be proven to me via some form of legitimate controlled testing where I can actually hear that difference and describe it. If I ever hear a difference, I will absolutely admit it.

For the record... I have more to lose from the following information that I am about to share, than I have to gain from it. I certainly gain NOTHING by lying about it or even exaggerating the truth. I think most people that know me well enough, they will tell you that while I do like to joke around a little, ultimately I am flat out going to shoot straight with you... and I may even hurt some feelings along the way, but I believe it is what it is... so why not just tell it like it is. I also have a very open mind, and have changed my mind on many things in the past. Yet, I realize that a man's opinion changed against his will, is of the same opinion still.

I decided it was time to do a small experiment to answer a few questions for myself, and thought, why not share it with the forum. It may be helpful to some. 

I recently purchased an Emotiva XPR-5 amp because I wanted a very powerful amp with a beefy power supply that we can use to power about any speaker that comes our way for our speaker evaluations. Do I need it for my personal home theater setup, probably not, but I like having it. It is an amp that includes five very powerful channels with XLR inputs that connects very well to my Onkyo 5509 preamp processor, as well as it has a power on trigger that is convenient... and I like the looks of it. Owning it makes me feel good.

I also own several Behringer EP2500 amps that I have used for my subwoofers in my home theater room, although I have also had one hooked up to my center channel speaker and also a pair of MartinLogan Acsents and a pair of MartinLogan Motion 12's... and probably some others that I don't remember. I have never thought much about the amps, they sounded fine to me and I never once thought of any of them as being even slightly inferior to any other amp I have owned. Granted a long time ago I may have had the thought in my mind that home amps were better than pro amps, but over the years that thought faded away. The EP2500 does not look that great in the light, particularly with those rack mount ears sticking out... and the fan is loud, so it has to be modified, and I can still hear it running when I get close to it. It is a fairly inexpensive amp that was rebadged to the EP4000 and runs about $379 at Parts-Express. You get a lot of watts per channel and a very good power supply with this amp... it is stable to 2 ohms and can drive pretty much any speaker you hook up to it.

I have heard several people claim pro amps are not musical. I have never heard of such myself... not even sure if I would know what musical vs 'not musical' is suppose to sound like. However, I know that my XPR-5 sounds pretty awesome... as good as the Rogue Cronus Magnum amp we had in our first speaker evaluation... as good as my Denon 4520 Receiver... and as good as the Anthem Integrated 225 amp we used in our last speaker evaluation. I wonder if any of those might be considered 'not musical'? If they are, then maybe I am missing something... not only me, but maybe Leonard, Wayne, Quenten, Joe, and Mark Seaton have no idea what musical is and we have all missed it during the speaker evaluations.

I have an extra EP2500 just sitting in my cabinet, so why not break out my OSD ATM-7 and hook up two channels of the XPR-5 and the EP2500... which is exactly what I did.

I split the Front output of the Onkyo 5509 to the L/R inputs of the XPR-5 and the 1/2 inputs of the EP500. Then using the exact same Canare 4S11 speaker cable (same length and same connectors) from each amp to the ATM-7. One amp to Input A and the other to Input B... with my MartinLogan speakers hooked to Output 1. This way I could instantaneously switch between each amp with the remote control.

Here's the setup:

  


Next I needed to level match each amp to each speaker. Fortunately this was relatively simple with the EP2500 having left and right gain controls. So... I level matched them to within 0.1db at 1kHz... which coincidentally they were matched to less than 0.5dB throughout the frequency range, other than on the left speaker (left channel of each amp) there was a 1.3dB difference at 20kHz. The difference was 0.5dB at 20kHz in the right speaker.

Here are those measurements:

 

The 3-4dB dip you see at 2kHz is from the Audyssey Pro compensation.

Here is the .mdat file:
View attachment XPR-5_vs_EP2500.mdat


Next... I cranked the volume on up to 0dB on the 5509... moderately loud... and commenced to listening to some of my favorite tracks. I varied the switching from short term to long term... no matter when I switched them, never once could I tell even the slightest of difference in sound. Had it not been for the very faint pop I could hear when hitting the button on the remote, I would not know the amps were switched from one to another. And I would challenge ANYONE to hear a difference and be able to identify which amp was playing on a consistent basis. I can tell you... it ain't gonna happen... or I will say I am 99.99% sure it won't happen. What I would have to say to anyone suggesting this Behringer EP2500 is not musical is... BOLOGNA!!! It sounds every bit as good as anything I have heard.

I am sure this comes as no surprise to some, but others will figure out some way to cry foul. No doubt it will fail to please everyone. All I can say is test it for yourself and you just might be surprised.

HOWEVER... I will still reserve that .01% for you naysayers. Luther Ward just finished up with a review on the Anthem Integrated 225 that he will be posting soon. I will have him send it back to me on our dime and I will test it against the EP2500 as well. Not only that... just in case anyone doubts my ears, Wayne (AudiocRaver) is flying over to my home on Monday, January 13th (Lord willing) and we are going to do some reviewing and testing together that entire week... he flies back out on Friday. I have several speakers here we can use... Prodigy's, Montis, Motion 12's, Studio 60's and the Arx A5's. I will even try to get up another amp or two. Wayne has marvelous ears... we'll see what he says about what he hears too. 

We might even allow someone else to come and visit with us for a day (at your own expense) and see if you can hear a difference. You can bring an amp if you want. If you are interested, let me know. 

While it is not the end all of comparison tests, it serves me well enough to shut the door as far as I am concerned with the myth that pro amps cannot sound as good as home amps. NO... I ain't selling my XPR-5 for other various reasons, but at least I don't have to wonder any longer if there really is a difference, at least between the EP2500 and the XPR-5... and I suspect several others in the very near future. Hey... as I said... it is what it is!

------------------------------------

*EDIT: Additional Comparisons and Measurements Added (12/24/13)*

After more thought, I decided it would be better to compare the XPR-5 with the EP2500 using the Arx A5 speakers. Previously I used the MartinLogan Montis, which are powered below 340Hz, so I was not hearing the two amps in the lowest frequency range from 40-50Hz to 340Hz, which could indeed influence what I was hearing. 

I also took measurements using Audyssey in Pro Logic llx mode, which is NOT how I listened to them. Granted it was more for level matching than anything else, but I still prefer to show the response sweeps in Pure Audio mode, which is how I compared the amps.

Here are the measurements of each speaker, respectively (Montis Left XPR-5/EP2500), (Montis Right XPR-5/EP2500), (A5 Left XPR-5/EP2500), (A5 Right XPR-5/EP2500):

  

View attachment xpr-5_vs_ep2500_montis_vs_a5.mdat


Something interesting to note is that in the Pure Audio mode, we do not see the difference at 20kHz that we can see in the Pro Logic llx mode measurements with Audyssey. Why would one mode show a difference in amp response and another mode not show it? Very strange.

Switching between the XPR-5 and the EP2500 on the Arx A5 revealed no differences that I could hear. Instantaneous switching was smooth and seamless. There is really not much more I can say about it. They sound absolutely identical (to me and my ears).

While I was at it, I decided to switch between the Montis and the A5... I know, not fair at all since you can buy a dozen pairs of A5 for the price of one pair of Montis. But still, I was curious. Of course this is one of those where I was fairly certain before hand that the A5 had met its match and well beyond, just from my listening to the Montis since they arrived. I love my A5 speakers when I am listening to them, but since I got the Montis in the house, the A5's have taken a back seat. There is no question the Montis is a far superior speaker in every way... far superior to anything that has EVER been in my house, and they should be. Nonetheless, I sat the Montis and A5 side by side, sharing their nearly identical sweet spot and proceeded to switch between the two. The only issue was I had to compensate the volume of the A5 by +6dB during the switch, so it was not as instantaneous as I would have liked, yet I could immediately tell the difference. The Montis just do everything better... more bass, much more well rounded bass, they are more dynamic, present more detailed imaging, more detailed everything, bigger soundstage, although the depth of soundstage appeared to be about the same. While I knew the Montis were better, placing them side by side makes it more evident, as sad as it is to say so. What I do find interesting is that it takes a $10K speaker to move the A5's out of the way. We do have a lot more speakers to test over the coming months (Lord willing), so there could be others, but these are the first speakers that I have noticed such a huge difference between speakers. Even my Prodigy's take a pretty serious back seat to the Montis. They too are better than the A5's, but only slightly in comparison to the Montis.

------------------------------------

What would I buy if I was choosing between the Emotiva XPA-2 (currently $799) and the Behringer EP4000 (the rebadged EP2500 currently $379) for two-channel music? It would really depend on the setup. If I were driving relatively efficient dynamic speakers, my equipment rack was in another room, I did not care about remotely powering on and off the amp, and did not care about the looks of the amp, I would probably pick the EP4000. If the amp were going to be in my main room, if I wanted to remotely power it on and off, if I were driving more difficult speakers (mainly electrostatic speakers), or if I simply wanted a better looking amp, I would spend the extra and get the XPA-2. I would not be concerned about the power output difference because either would have plenty of power to drive nearly any speaker. I believe I would prefer the power supply of the XPA-2 since it appears to be more robust. The biggest drawback to having the EP4000 out in the room is the fan noise... it would have to be replaced, which would void the warranty. I also like having the remote power trigger on the XPA-2 so that I can easily power it on and off with my remote macro. In my setup, this means I would choose the Emotiva XPA-2.

What about the Emotiva XPA-5 vs three EP4000 amps (to obtain 5 channels)? I would save money and space and power outlet use by going with the XPA-5. Granted the XPA-5 is about half of the power of the EP4000, but the XPA-5 is going to be plenty of power to drive nearly any speaker out there. I don't really care to have to buy 3 more amps and worry about locating them and plugging them up. Hands down, I would choose the XPA-5 over the EP4000 amps... and if I could afford it, I would step up to the XPR-5 for my own personal use, which is what I have and what I plan to keep. The XPR-5 is a 94lb BEAST... and it makes me feel confident that I have the right amp powering my MartinLogans.

Overall, I personally just plain feel better running the Emotiva amps for my main channels than I do the Behringers. I need to feel good about what I own and I fully understand this playing an important role in what we purchase.


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## JBrax

Wow Sonnie looks like you spent a little time with that endeavor. Very good read and I must admit I've often thought about adding an emotiva amp to my setup. Would I gain anything from it? I suspect no due to having very efficient speakers but I think they are cool looking. Like you said it makes you feel good and that would most likely be my only gain.


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## kingnoob

Very Interesting information ! 
Does Behringer make any good amps similar to EUROPOWER EP2500 ??It says its discontinued what is there typical price would you suggest this to me for home theater/music?


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## mikesp1

Here is a review of the Behringer amp i found on the iternet wich is clos to my own experience:

I originally purchased a pair of these amps to use for a DIY subwoofer project. That project never happened. But I used one of these amps to power a pair of Elemental Designs subs in a custom built enclosure for HT. I was previously using a Carver TFM-35. The sound tightened up considerably with the Behringer amp. The amp was very dynamic and never ran more than slightly warm during the most demanding movie scenes. So, for subs I would say this amp is exceptional. Next, I used the pair of amps bridged mono to power AV123 LS6 speakers. The amp performed better than I expected. For a pro solid state amp, it has a surprisingly pleasing tonal balance. The bass was tight and authoritative, mids were full and even slightly warm, highs were smooth, but not as detailed as most "audiophile" amps. I later upgraded to an Odyssey Stratos Extreme and the difference was quite noticeable - the highs were more detailed, and overall a more refined sound. But for the non-audiophile that is mostly into HT, I doubt there's a better amp for the price.


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## chashint

So glad you are doing this.
Having never messed with the REW how big of a deal is it to run a comparo measurement ?
Can you replace the pro amp with a cheap AVR ?

Any chance of getting the people who voted disagree in this thread http://www.hometheatershack.com/forums/av-home-theater/9024-ten-biggest-lies-audio.html in there to give it a listen? 

Yeah I know...always asking for more...just excited you have started down this path...

Thanks for all the work you do.


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## mikesp1

That REW measurement will say nothing about how the amp sounds in the real world.

Does it give an impresson about, chanenel separation, air around the instruments, micro details, color, etc? nada.

It only measures the interaction between your speakers and the room.


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## Sonnie

kingnoob said:


> Very Interesting information !
> Does Behringer make any good amps similar to EUROPOWER EP2500 ??It says its discontinued what is there typical price would you suggest this to me for home theater/music?


EP4000 ... see my link in the first post.




mikesp1 said:


> Here is a review of the Behringer amp i found on the iternet wich is clos to my own experience:
> 
> I originally purchased a pair of these amps to use for a DIY subwoofer project. That project never happened. But I used one of these amps to power a pair of Elemental Designs subs in a custom built enclosure for HT. I was previously using a Carver TFM-35. The sound tightened up considerably with the Behringer amp. The amp was very dynamic and never ran more than slightly warm during the most demanding movie scenes. So, for subs I would say this amp is exceptional. Next, I used the pair of amps bridged mono to power AV123 LS6 speakers. The amp performed better than I expected. For a pro solid state amp, it has a surprisingly pleasing tonal balance. The bass was tight and authoritative, mids were full and even slightly warm, highs were smooth, but not as detailed as most "audiophile" amps. I later upgraded to an Odyssey Stratos Extreme and the difference was quite noticeable - the highs were more detailed, and overall a more refined sound. But for the non-audiophile that is mostly into HT, I doubt there's a better amp for the price.


Very subjective and not a controlled comparison. It is hard to put faith in these kinds of comparisons. 

REW helps us see that the measurements are the same... and that they are going to likely sound the same with the same response, provided they are both good quality amps, which these are.

My ears confirmed to me that the EP2500 is indeed an "audiophile" amp... and it was done with very controlled A/B switching... not by listening... swapping out the amps with time in between and then listening again, which is a near impossible way to compare amps. Sorry I busted your bubble here Mike. It is what it is.




chashint said:


> So glad you are doing this.
> Having never messed with the REW how big of a deal is it to run a comparo measurement ?
> Can you replace the pro amp with a cheap AVR ?
> 
> Any chance of getting the people who voted disagree in this thread http://www.hometheatershack.com/forums/av-home-theater/9024-ten-biggest-lies-audio.html in there to give it a listen?
> 
> Yeah I know...always asking for more...just excited you have started down this path...
> 
> Thanks for all the work you do.


It is not complicated at all to compare the response of amps with REW. You can either get a switch like I have or you can simply swap over all your cables.

I plan to compare more amps... it is very easy to do so the way I have it setup. We will do some blind testing too once Wayne gets here.




mikesp1 said:


> That REW measurement will say nothing about how the amp sounds in the real world.
> 
> Does it give an impresson about, chanenel separation, air around the instruments, micro details, color, etc? nada.


Where do you think I was at Mike... in a dream world? I think that might be where you reside my friend. You are now arguing just to be arguing and cannot accept the truth of this test. 

The measurements are not there to necessarily tell you how the amps sounded... they are there to show you that the amps were level matched. Did you level match your amps within 1dB before you compared? It is a known fact that only a few dB's can cause one amp to seem to sound better than another. This is the purpose of the measurements. 

The measurements can help identify different sounds if there are frequency mismatches. Did you frequency match your amps before you compared? If one of those amps had a 5 dB peak from 1kHz up to 2kHz... I am quite certain I would be able to hear a difference between the two during switching. So measurements can indeed help you know how amps will sound in the real world... along with our ears.

Plus... I never claimed the measurements told us how the amp sounded, but I clearly told you how they both sounded according to my ears. Again... my ears heard no differences. Imaging... soundstage... clarity... detail... all was excellent with both amps. And I think I have become pretty good at identifying those characteristics. Nonetheless... it ain't gonna matter if 100 people tell you that there is no difference, it is apparent you are going to argue about it. So you may as well just move on and argue somewhere else... there are other forums that will put up with it, but we don't here. Accept the truth and move on.


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## chashint

mikesp1 said:


> That REW measurement will say nothing about how the amp sounds in the real world.


Since I am part of the electrical engineering world and not the acoustical engineering world I will not make statements about what the capabilities of measuring and analyzing sound are at this point in time.
Having said that I am well versed on what can be measured in the electrical realm and how to make those measurements.
I would be shocked to learn acoustical engineering does not have the ability to accurately measure, analyze, and compare sound with orders of magnitude more resolution and accuracy than the human ear is capable of resolving.

Is REW a tool that fits that description? Quite frankly I don't know. Lots of people here seem to think the measurements obtained using it have merit.

It's too bad you are not local to Sonnie so you could experience a listening session for yourself.


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## mikesp1

I forgive you Sonny, my wife also does not hear the difference between a 200 and a 10000 dollar speaker.


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## chashint

I have thought about going down the REW path just for the learning experience, but part of that learning experience would include documenting the defects of my room and speakers.
Truth is I am much better off not knowing.
Once I start down a rabbit hole my OCD kicks in and I have to fix it.
That's a great trait to have at work when something has to be fixed, but not so much at home when it comes to my audio system.
Best just to remain happy and let sleeping dogs lie.


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## chashint

Most people can readily hear a difference between any two different speakers regardless of any price difference or lack of, sorry your wife is tone deaf that must drive you crazy.

On the topic at hand though...
Up to this point no one has been able to differentiate/identify a 200 vs 10000 dollar amplifier in a controlled listening test.


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## mikesp1

There are two possibilities:

People have different hears.

Or

Something in the audio chain is not making it verry revealing.

Anyway, no hard fealings, but i do know what i heard between that Behringer and other amps and the difference for me is hughe.

That said i believe nor Sonny, nor i can make a statement wheter it is rather scientific or by human hears.

To make a statement wheter this Behringer is as good as every good home amp we need a pannel of people and a reveiling system, nobody is going to hear a difference if yo connect those amps on 10dollar ipod speakers.


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## JBrax

chashint said:


> I have thought about going down the REW path just for the learning experience, but part of that learning experience would include documenting the defects of my room and speakers. Truth is I am much better off not knowing. Once I start down a rabbit hole my OCD kicks in and I have to fix it. That's a great trait to have at work when something has to be fixed, but not so much at home when it comes to my audio system. Best just to remain happy and let sleeping dogs lie.


You have just perfectly summarized why I have avoided REW.


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## mikesp1

chashint said:


> .
> Up to this point no one has been able to differentiate/identify a 200 vs 10000 dollar amplifier in a controlled listening test.


Can you make this hard? Prove it? Was the Behringer part of the test?

Which 200 and wich 10000 dollar amplifiers were tested?

Come one, do you guys realy hear and believe what you are saying?


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## mikesp1

chashint said:


> .
> Up to this point no one has been able to differentiate/identify a 200 vs 10000 dollar amplifier in a controlled listening test.


I stop posting on this thread. A lot of nonsense are been told.

I have an open mind and if an 200 dollar amp can do the job as good as a10000 dollar amp i wil certainly use it.

Prove it.


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## hjones4841

Sonnie: What about the S/N ratio on the Behringer? I have always thought that pro amps might have more residual noise than good home amps.


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## ajinfla

OSD?? Should be using a "OCD" for such endeavors 

Note: Sonnie, REW as used, is a poor method for such measurements without considerable variability. Your setup isn't the NRC type one . But I'm with you otherwise.



mikesp1 said:


> There are two possibilities:
> People have different hears.
> Or
> Something in the audio chain is not making it verry revealing.


What about the 3rd possibility Mike? That your perceptions are not an unerring representation of reality, but merely *your* perceptions, subject to a great deal of error, unless accounted for? Why do you willfully and repeatedly ignore this?



mikesp1 said:


> Anyway, no hard fealings, but i do know what i heard between that Behringer and other amps and the difference for me is hughe.


No one disputed this is what you "heard" Mike. But you see only one (maybe two) possibilities, while rejecting all others.



mikesp1 said:


> That said i believe nor Sonny, nor i can make a statement wheter it is rather scientific or by human hears.
> To make a statement wheter this Behringer is as good as every good home amp we need a pannel of people and a reveiling system, nobody is going to hear a difference if yo connect those amps on 10dollar ipod speakers.


"We" don't need to do anything. *You*, whose claims, based solely on your perceptions and pathological "test" methods, are in contradiction of established science, are burdened with the proof. Logic 101. Just like a negative cannot be proven.



mikesp1 said:


> I stop posting on this thread. A lot of nonsense are been told.
> I have an open mind and if an 200 dollar amp can do the job as good as a10000 dollar amp i wil certainly use it. Prove it.


See above. FYI, that's been done, but you can never accept this as an audiophile. The onus is squarely on *you*, to demonstrate ability to differentiate, with amps behaving linearly into loads. One last time, no one claims amps cannot be driven into non-linearities into loads.
But there is no reason to believe that is your culprit, given your beliefs, expectations and methods.


p.s. btw Mike, if you "hear" noises on your roof Wed, I'll believe you. Just don't expect me to accept it's Santa Clause, because your ears expected him and...said so 
Merry Christmas

cheers


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## Mike0206

Well I'm no where near as qualified to make an assessment of the differences between home and pro amps as some of you here, after all I'm a hobbyist and enthusiast not a professional. However in my mind an amp, even if making an audible difference in sound, would be the least noticeable factor in the system. Above all it would be the speakers themselves making the largest difference, then the processor, then the source material (CD, iTunes, SACD etc..) then the amplifier if any difference at all. Just my .02.


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## ajinfla

Mike0206 said:


> in my mind an amp, even if making an audible difference in sound, would be the least noticeable factor in the system. Above all it would be the speakers themselves making the largest difference, then the processor, then the source material (CD, iTunes, SACD etc..) then the amplifier if any difference at all. Just my .02.


There are a myriad of reasons why an amp can sound very different within a system context, all measurable of course. Clipping and other such non-linear behavior can range from nearly indiscernible, to painfully obvious. Tubes clip differently from SS. Output impedances can vary, changing frequency responses coupled to the load. etc, etc....and that's just the physical reasons, without getting into the psychological differences, which are also very, very real.
We have to be very clear with the caveats and specifics of what we are referencing, even if audiophile can't comprehend or will simply ignore them, then label us deaf, lacking system "revealingness", in the "all amps sound same" strawman camp, etc, etc. 



Mike0206 said:


> I'm a hobbyist and enthusiast not a professional.


Neither am I, though I play one on TV. 
Plus I did stay at a Holiday Inn Express last night.

cheers


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## Mike0206

Yeah sorry for not clarifying what I mean by amplification comparisons. I meant two amps level matched and not ran into clipping with the same wpc. Of course an amp can sound different once distortion begins and at different harmonic orders so that's where a difference would start to occur. But we are talking about not clipping the amps.


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## dougc

mikesp1 said:


> I stop posting on this thread. A lot of nonsense are been told.
> 
> I have an open mind and if an 200 dollar amp can do the job as good as a10000 dollar amp i wil certainly use it.
> 
> Prove it.


I have the same opinion, but is tilted to the other direction. Why would I spend $9800 more on an amp when the difference cannot be proven? I would pay more money for quality customer service, locally built products, efficiency, and sad to say, but something that looks nice.


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## Sonnie

mikesp1 said:


> I forgive you Sonny, my wife also does not hear the difference between a 200 and a 10000 dollar speaker.


My wife has one up on yours then... because she can clearly hear the difference between our $200 Infinity speakers and our $10,000 Montis. But we are not talking about speakers, we are talking about amps. 




chashint said:


> I have thought about going down the REW path just for the learning experience, but part of that learning experience would include documenting the defects of my room and speakers.
> Truth is I am much better off not knowing.
> Once I start down a rabbit hole my OCD kicks in and I have to fix it.
> That's a great trait to have at work when something has to be fixed, but not so much at home when it comes to my audio system.
> Best just to remain happy and let sleeping dogs lie.


Probably a good call... although isn't it just killing you that there _*COULD*_ be something amiss that you could fix? :devil:




mikesp1 said:


> Anyway, no hard fealings, but i do know what i heard between that Behringer and other amps and the difference for me is hughe.


Again... in most cases even the golden ear audiophiles only hear subtle differences in amps... not "huge" differences. If you are hearing "huge" differences, something is wrong with one or the other amp. Check the dip switches... level match them and then frequency match them. Do the listening test the right wait and quit relying on your forgetful brain.




mikesp1 said:


> To make a statement wheter this Behringer is as good as every good home amp we need a pannel of people and a reveiling system, nobody is going to hear a difference if yo connect those amps on 10dollar ipod speakers.


I am not using $10 iPod speaker here Mike. There is nothing in my system that is going to cause anything else to NOT be revealing. 




mikesp1 said:


> Can you make this hard? Prove it? Was the Behringer part of the test?
> 
> Which 200 and wich 10000 dollar amplifiers were tested?
> 
> Come one, do you guys realy hear and believe what you are saying?


If you could read as good as you claim you can hear, you would read my comment to you in your thread about the following... read it and weep. While it doesn't compare a $200 amp vs a $10,000 amp, it does compare a $200 amp to a pair of $14,000 monoblocks. 



> There has been a lot of hot chatter on the E-mail circuit over the past couple of months about the Steve Maki and Steve Zipser challenge in Miami. I thought you would appreciate a complete recount of the events. Zipser, a high-end salon owner, had issued a challenge that he would pay the airplane fare of any interested party who wanted to see him prove he could hear the differences between amplifiers.
> 
> On Sunday afternoon, August 25th, Maki and I arrived at Zipser's house, which is also Sunshine Stereo. Maki brought his own control unit, a Yamaha AX-700 100-watt integrated amplifier for the challenge. In a straight 10-trial hard-wired comparison, Zipser was only able to identify correctly 3 times out of 10 whether the Yamaha unit or his pair of Pass Laboratories Aleph 1.2 monoblock 200-watt amplifiers was powering his Duntech Marquis speakers. A Pass Labs preamplifier, Zip's personal wiring, and a full Audio Alchemy CD playback system completed the playback chain. No device except the Yamaha integrated amplifier was ever placed in the system. Maki inserted one or the other amplifier into the system and covered them with a thin black cloth to hide identities. Zipser used his own playback material and had as long as he wanted to decide which unit was driving the speakers.
> 
> I had matched the playback levels of the amplifiers to within 0.1 dB at 1 kHz, using the Yamaha balance and volume controls. Playback levels were adjusted with the system preamplifier by Zipser. I also determined that the two devices had frequency response differences of 0.4 dB at 16 kHz, but both were perfectly flat from 20 Hz to 8 kHz. In addition to me, Zipser, and Maki, one of Zip's friends, his wife, and another person unknown to me were sometimes in the room during the test, but no one was disruptive and conditions were perfectly quiet.
> 
> As far as I was concerned, the test was over. However, Zipser complained that he had stayed out late the night before and this reduced his sensitivity. At dinner, purchased by Zipser, we offered to give him another chance on Monday morning before our flight back North. On Monday at 9 a.m., I installed an ABX comparator in the system, complete with baling-wire lead to the Yamaha. Zipser improved his score to 5 out of 10. However, my switchpad did develop a hang-up problem, meaning that occasionally one had to verify the amplifier in the circuit with a visual confirmation of an LED. Zipser has claimed he scored better prior to the problem, but in fact he only scored 4 out of 6 before any difficulties occurred.
> 
> His wife also conducted a 16-trial ABX comparison, using a 30-second phrase of a particular CD for all the trials. In this sequence I sat next to her at the main listening position and performed all the amplifier switching functions according to her verbal commands. She scored 9 out of 16 correct. Later another of Zip's friends scored 4 out of 10 correct. All listening was done with single listeners.
> 
> In sum, no matter what you may have heard elsewhere, audio store owner Steve Zipser was unable to tell reliably, based on sound alone, when his $14,000 pair of class A monoblock amplifiers was replaced by a ten-year old Japanese integrated amplifier in his personal reference system, in his own listening room, using program material selected personally by him as being especially revealing of differences. He failed the test under hardwired no-switching conditions, as well as with a high-resolution fast-comparison switching mode. As I have said before, when the answers aren't shared in advance, "Amps Is Amps" even for the Goldenest of Ears.
> 
> Tom Nousaine
> Cary, IL





mikesp1 said:


> I have an open mind and if an 200 dollar amp can do the job as good as a10000 dollar amp i wil certainly use it.
> 
> Prove it.


See above... now keep your word and go find a good used Yamaha AX-700 amp. You are going to be just as happy as if you owned a pair of $14,000 monoblocks.




mikesp1 said:


> I stop posting on this thread. A lot of nonsense are been told.


Exactly... and the nonsense will stop as soon as you quit posting. Thank you!




hjones4841 said:


> Sonnie: What about the S/N ratio on the Behringer? I have always thought that pro amps might have more residual noise than good home amps.


-100dB

The fan noise is another matter. If used out in your room and not hidden, you would need to modify the fan, which will likely void the warranty. It is a risk... and while Behringer equipment has been fairly reliable, I know of a few instances where their amps have failed... including one channel of one I own.

No doubt there are drawbacks to using the EP2500 or EP4000... but sound quality is not one of them.




ajinfla said:


> OSD?? Should be using a "OCD" for such endeavors


OSD is the model of the A/B switch/speaker selector I was using. OSD Audio... but it can make you OCD. :dumbcrazy:




ajinfla said:


> Note: Sonnie, REW as used, is a poor method for such measurements without considerable variability. Your setup isn't the NRC type one . But I'm with you otherwise.


"poor"? C'mon man. Maybe not perfect, but it is indeed very good for level matching and response measurements. It is actually pretty good for a lot of things... even perfect for some. Nonetheless... it served the purpose here very well... far from "poor". :foottap:




ajinfla said:


> Plus I did stay at a Holiday Inn Express last night.


This has helped me tremendously in the past.


----------



## ajinfla

Sonnie said:


> "poor"? C'mon man. Maybe not perfect, but it is indeed very good for level matching and response measurements. It is actually pretty good for a lot of things... even perfect for some. Nonetheless... it served the purpose here very well... far from "poor". :foottap:


"Poor" in the sense of method. Level matching of this sort, should be done with frequency dependent voltages at the speaker terminals. Acoustic measurements are insufficiently accurate, especially outside an anechoic space, where ambient noise levels will affect every measurement and create variability.
Obviously the precision of the matching did not affect the outcome.

But maybe that's because the OSD (OCD?) is mid-fi (too cheap) and is a confounder, "masking" the differences.

Or because your cables are lying on the carpet  and there are static charges interacting with and modulating the induced magnetic fields, greatly confusing the electrons in the wires, creating indecision, unruly behavior and general unmusicality. 
Which would of course mask the differences we "know" are there. 
Since someone on the internet said so.

cheers


----------



## Sonnie

Yeah... been thinking that I probably need some of those cable risers. :whistling:


----------



## morca

Very Interesting test Sonnie :T


----------



## RTS100x5

Sonnie said:


> Yeah... been thinking that I probably need some of those cable risers. :whistling:


LOL ...I agree 100% that 99% of the amps on the market are going to sound pretty much the same given a equal setup procedure... That said I recently installed an EMOTIVA XPA 3 to drive some custom build speakers .... the sole purpose was to up the dynamic headroom capacity as the YAMAHA receiver beforehand was inadequate in this regard... 
As a veteran enthusiast I also maintain that the biggest difference in any audio setup is going to be the speaker / source combination....meaning no $100k speaker system is going to make a 128k mp3 source shine just as no $3k DAC is going to shine through a set of inferior speakers....
The only amps that are supposedly different is sound quality are tube amps... and as long as Ive been installing, the only tube setup Ive ever heard was a low powered Heath Kit powering some Polk speakers... I cant even say that I heard it long enough to tell if it was any different than a switching amp....
It still makes me laugh when I pick up one of those audiophile mags and read about $40k speaker wire (which they carry on AMAZON now) and various products all of which have their own "sonic character" :sarcastic:
The only true upgrades IMO are the sources and more importantly the speakers .... everything else is just icing on the cake .... including my PANGEA 9 ga. AC cord on my PIO ELITE AVR :whistling:


----------



## Sonnie

I spoke with Frank at Van Alstine Audio about his ABX Test Box. He is currently working on the second generation box that will handle 2 preamps, 2 amps and 3 pairs of speakers, all simultaneously... and will test them randomly with no indicator lights for what amounts to blind testing. This one will run about $1,000 and is about six weeks out. We will purchase one as soon as it becomes available... just to make sure there are no issues. I suspect the one we have is probably good enough, but the AVA box should quieten at least a few doubters. Of course there are some we will never quieten... even with 100% scientific proof. There are some out there that claim there is no truth, but I am not sure how know that to be true.


----------



## chashint

mikesp1 said:


> I stop posting on this thread. A lot of nonsense are been told.
> I have an open mind and if an 200 dollar amp can do the job as good as a10000 dollar amp i wil certainly use it.
> Prove it.


Even though you won't believe it here is the "proof" you have demanded...
http://www.tom-morrow-land.com/tests/ampchall/index.htm 
The double blind amp test has been done over and over and no one has ever guessed which amp was which in a statistically meaningful way.
Cheap amps vs "audiophile" amps have been tested and could not be accurately identified as long as both were operated below the least powerful amp's clipping threshold.

If what you proclaim is true using your choice of source material you should be able to identify your amp vs the Behringer 100% of the time in a double blind listening test.
If you were to be successful in even achieving even a 70% success rate you would be the first to achieve this distinction.

I started this post and then I had to go out for a while, I see in the meantime there are even better examples of "proof" that have been posted.

You know the majority of people here are not anti high end (ie expensive) equipment...at least I am not...even those that are 100% objectivist for the most part buy more than the bare minimum in electronics...but an amplifier is simply an amplifier, its job is to increase the amplitude of the signal fed into it.

Good day to you sir, I will not correspond to you on this again.


----------



## Almadacr

I always prefered professional amps because they can deliver but they are or were ugly to keep right beside our new receiver . Do they sound different ... IMO no . To my test in a environment that i was familiar ( not my room ) but familiar with the gear and acoustics , a Classe vs Crown they both deliver the goods the difference ???? The price tag being the crown less $6500 . 

IMO the ones that think that there are differences are the ones that buy exoctic speaker cables and power cables . I belive more in room acoustics and a change of speakers to do the job .

If there was a difference the first ones that would make the change would be ..... professional musicians , if there's anything that changes the tone intended by the artist believe me that would be out of his options .


----------



## Savjac

Interesting findings and write up. 
I believe Sonny has no axe to grind and frankly his word is golden and beyond reproach. 
I do not believe much of anything Tom Nousaine has to say, he just seems disingenuous to me. Right or wrong I don't know and it does not matter.

Also, I strongly do not believe we can measure everything thing electronically or otherwise but in reality that is not what this thread is about. A postulation was presented and a gentlemen took the time to work though it with an open mind,that that is what deserves respect.

I have no argument here, over the years of listening, it is my belief I can hear a difference between some, not all, amplifiers reproducing music. I have to admit that Sonnie makes a very good case that I may not be entirely on target. The words presented in his findings are more than just old repeated rhetoric and that troubles me a good bit. Where did I go wrong....or did I ?

I believe him, I do, now I need to back track and find why I have always tended to the opposite direction, this is very intriguing. This will be a slow process, I don't have easy access to as many amps as the good old days, but what the  it will be a worthy goal.

Thank You for the work/play Sonnie. (I am still trying to convince my wife to come up with center channel money but she kinda laughs and things I am not right upstairs..:coo coo


----------



## tonyvdb

LOL at cable risers :huh:
I've personally gone from using the built in amp of my receiver to driving my mains with an external Samson "pro" amp and can say that their was no audible difference in sound quality. The only advantage it gave me was my receiver stays cooler. 
My only concern with the Behringer amps in general is noise, all the amps I have every heard from them have a high noise floor and on highly sensitive speakers it's noticeable.


----------



## Sonnie

-100dB is respectable... I certainly can't hear it.


----------



## Tonto

Very interesting read. Glad you are finally taking the time to do this test. I know we posted about it for a while, but thought it was back burnered. That ABX Test Box also sounds like a nice piece of equipment. I think it will be an excellent resource in the future speaker evals. Which you may have to consider extending, since "more = longer." I would like to see some tube vs ss amp comparisons during the speaker evals.

And just to reinforce what has already been said:

I have personally worked with Sonnie, Wayne & Leonard in the first eval. I'm a pretty good judge of caracter & feel these guys do their best to bring honest, real world perceptions of what they hear. I am impressed by their candid, straight forward nature. They enjoy this hobby & bring this for our consideration. They don't ask for anything except truth & proof. And in this world of snake oil, there are few people willing to state truth. Cudos! Proud to be a member.


----------



## Wayne A. Pflughaupt

hjones4841 said:


> What about the S/N ratio on the Behringer? I have always thought that pro amps might have more residual noise than good home amps.


Not sure I’d trust Behringer’s noise specs. After all, they spec the BFD at 96 dB unweighted, and it’s nowhere near that – the thing is really noisy in +4 dB mode. I’ve used other equalizers with the same noise spec that were dead silent.

A good way to get an idea how quiet the amp in question is compared to a reference amp is to first level-match the two, then switch the pre-amp to an unused input and turn the pre-amp volume all the way up. Then, up close and personal to the speakers, you can compare the two amps to see of one is generating more background noise than the other. (An easy way to do this is to connect a speaker to each amp, and move both speakers next to each other.)

If one amp makes more noise than the other, it’s good info to know, but probably won’t make a difference as long as it’s not audible at the listening position at any volume level you run your system at.

Regards, 
Wayne


----------



## kingnoob

Yes a Pro amp can probably run Klipsch Icon speakers well, I wish I would have got the bigger towers.
Sonnie has heard speakers/amps so good I could probably only dream to hear lol 

How quiet are the PA amps ??I need something silent for HD audio but can you push 300 watts into a Klipsch Icon Kf 26 tower?? They seem like they aren't loud enough on onkyo when running 7ch.
They are Bi-ampable but they dont sound any better when I tried it out.


----------



## kingnoob

Almadacr said:


> I always prefered professional amps because they can deliver but they are or were ugly to keep right beside our new receiver . Do they sound different ... IMO no . To my test in a environment that i was familiar ( not my room ) but familiar with the gear and acoustics , a Classe vs Crown they both deliver the goods the difference ???? The price tag being the crown less $6500 .
> 
> IMO the ones that think that there are differences are the ones that buy exoctic speaker cables and power cables . I belive more in room acoustics and a change of speakers to do the job .
> 
> If there was a difference the first ones that would make the change would be ..... professional musicians , if there's anything that changes the tone intended by the artist believe me that would be out of his options .


MY room has bad acoustics sadly, XT32 helped a lot though...


----------



## Sonnie

Wayne A. Pflughaupt said:


> Not sure I’d trust Behringer’s noise specs. After all, they spec the BFD at 96 dB unweighted, and it’s nowhere near that – the thing is really noisy in +4 dB mode. I’ve used other equalizers with the same noise spec that were dead silent.
> 
> A good way to get an idea how quiet the amp in question is compared to a reference amp is to first level-match the two, then switch the pre-amp to an unused input and turn the pre-amp volume all the way up. Then, up close and personal to the speakers, you can compare the two amps to see of one is generating more background noise than the other. (An easy way to do this is to connect a speaker to each amp, and move both speakers next to each other.)
> 
> If one amp makes more noise than the other, it’s good info to know, but probably won’t make a difference as long as it’s not audible at the listening position at any volume level you run your system at.
> 
> Regards,
> Wayne


Just tried it... actually the EP2500 is quieter than the XPR-5... but neither can I notice unless I get my ear right next to the speaker. I also have a low hum with the XPR that is not there with the Behringer. Now that is going to drive me crazy.


----------



## kingnoob

Sonnie said:


> Just tried it... actually the EP2500 is quieter than the XPR-5... but neither can I notice unless I get my ear right next to the speaker. I also have a low hum with the XPR that is not there with the Behringer. Now that is going to drive me crazy.


nothing is louder than my old sony receiver it was so loud ...I cannot use it to power my 8,9 channels.

I am pretty sure Sony was broken or something.


----------



## Wayne A. Pflughaupt

Sonnie said:


> Just tried it... actually the EP2500 is quieter than the XPR-5... but neither can I notice unless I get my ear right next to the speaker. I also have a low hum with the XPR that is not there with the Behringer.


Yet, the XPR is rated at what should be a stellar >109 dB @ rated power. Behold the “magic” of the A-weighted specification standard that most home audio manufacturers use!

Regards, 
Wayne


----------



## Savjac

Sonnie said:


> Just tried it... actually the EP2500 is quieter than the XPR-5... but neither can I notice unless I get my ear right next to the speaker. I also have a low hum with the XPR that is not there with the Behringer. Now that is going to drive me crazy.


Funny you mention this, my Emotiva has a hum as well. I can't hear anything in the speakers but in the quiet room there it is.


----------



## Savjac

kingnoob said:


> Yes a Pro amp can probably run Klipsch Icon speakers well, I wish I would have got the bigger towers. Sonnie has heard speakers/amps so good I could probably only dream to hear lol  How quiet are the PA amps ??I need something silent for HD audio but can you push 300 watts into a Klipsch Icon Kf 26 tower?? They seem like they aren't loud enough on onkyo when running 7ch. They are Bi-ampable but they dont sound any better when I tried it out.


Receivers do tend to loose rated power as more channels are run, what is loud enough ?


----------



## kingnoob

Savjac said:


> Receivers do tend to loose rated power as more channels are run, what is loud enough ?


The amp can power then pretty well I just lose some clarity with the Icon Horn tweeters at Reference level:help: Amp must be pushing its power at REF lvl.


----------



## AudiocRaver

Sonnie sure has a way of getting a conversation going, doesn't he?

I will throw in a few thoughts...

*Pro Amps*
The kind of amp I think of in this category is the kind used in arenas and concert sound, like Crown, QSC, ElectroVoice, etc. - there are many excellent brands. I own a Crown (forgot the model) that is speced at 400 w/ch into 8 ohms. It has been used for a lot of critical listening, and I have always been delighted with its "sound," which is... no "sound" of its own at all, that I can tell. Part of what I like about a pro amp is the robust design, made to handle temperature extremes, run at full power for hours on end, handle any kind of load without instability, take tons of abuse with no complaints. With all that robustness, and then me running it in a totally non-stressful fashion, it should stay pretty transparent, no? Its specs are excellent, there is nothing done to make it robust that sacrifices any key specs, just the opposite. It is made to run with extremely low distortion under crazy conditions. So what I ask of it is a walk in the park.

*Is My Crown Power Amp Musical?*
If it were not such a beast, I would heft it down to Sonnie's place in January for some scrutiny. I would like to know. Maybe some audible difference lies beyond the current state of the art to measure and specify. Possibly. If so, the only option left is to turn the human ear into a measuring instrument which outputs objective data.

*Being Objective*
In subjective matters, like the ability of the human ear to perceive very subtle differences in sound, imagination can play a big role in the forming of our perceptions. This is not a new concept. There are vital questions to ask oneself: "_Can I trust these subjective impressions?_ _Did I make them up?_ _Is it possible that I imagined there to be a difference that does not actually exist?_"

Human imagination can be a wonderful thing. Sometimes its benefits from a little skepticism to keep it grounded in reality.

*A-B Testing*
What kind of testing can help us do this? Some claim that only long-term testing can reveal the subtle differences between amplifiers. Okay, then devise an A-B test that involves long-term testing. Ultimately it needs to accomplish two things: 1) A blind choice of some kind is made between the specimens under test, and 2) That choice can be made over and over again accurately. Only then is the outcome objective and meaningful.

When it comes to questions of one's ability to even hear this kind of fine detail reliably, believing it without proof is nothing more then a faith-based opinion. The listener who does not have the time or resources to engage in a process to prove what they think they can hear can be forgiven. So can the listener who does not know how to go about it. The listener who wants it all to remain an unproven mystery, or an unprovable mystery, can simply say it is a matter of faith and be done with it. I respect that. The truly indifferent listener will not even engage in this conversation. I respect that, too. Who does that leave? Could there be some fear of being proven wrong? That is not hard to conceive of. There are those who have a lot invested in "being right" about something that is unprovable.

This thread and others like it about audio are mainly about a willingness to get to proven truths. To those who believe short-term A-B testing to be ineffective, help us devise longer-term tests, or whatever kind of test it takes to be able to come up with proof. Consider this a sincere invitation.

*A-A Test Step*
A valid alternative step in A-B testing is inserting an occasional A-A Step (that does NOT mean being driven to drink!). The listener knows that at any switch point in the listening test, the controller may choose not to switch from A to B. Now the listener must first ask at each switch point, "Did a change actually take place? Can I hear a difference at all?" If so, then the listener continues evaluating the difference.

This forces the listener to truly listen at each switch point, not just settle into a back-and-forth pattern with an overall 50 percent chance of being right by guessing.

*REW, Tools, Bench Tests*
Tools are tools, sometimes they are more helpful than others.

It is true that bench tests can miss things. I own two of the Behringer A500 power amps, am pretty happy with them, BUT - sometimes the distortion is high with low output levels, sounds like 5% or more. An engineering-type reviewer once politely told me I was crazy or imagining things. It seems to happen after playing loud for awhile and then playing a quiet passage with mainly lower-midrange tones so distortion components stand out. Is there a bias voltage shifting, affecting crossover distortion? Did the reviewer bench test distortion under THAT set of conditions? No. But with more information, one could probably devise an effective test.

I was working for a small pro audio manufacturer back in the days when Transient Intermodulation Distortion (TIM) was being discovered (understood). John Monforte, a prominent voice in the audio industry for years, was our circuit designer at the time, and had a hard time convincing management that TIM existed. He finally devised a circuit that measured well but sounded terrible under the right conditions. Then our products got better. Our tools get better, too.

It is OK for our ears to challenge audio science. It is simply incorrect to assume that tools are useless or that good sound is unmeasurable.

*Audible Circuit Contributions*
The idea that every component in an amplifier contributes to its "sound" defies engineering principles. Part of what makes a design effective is the degree to which individual component variables or characteristics are either rendered to "don't care" status or are understood so they can be properly controlled. It is true that a bad design can sound bad. With extremely rare exceptions, there is no validity in the notion that a well-thought-out, well-implemented design can be improved by substituting "gourmet capacitors" or "better sounding fuses."

*Objective = "No Fun?"*
Being objective does not kill the joy in the music or the sound. It leads to a richer subjective experience. We now have better microphones, cleaner amplifiers, more accurate speakers, all because people got objective about things they were hearing. What will the state of the art be in 50 years? Who knows, but it will be amazingly fun, and it will happen because of objective work being done today.

*A-B Testing In January*
Of course our tests will not quiet the controversy about these matters. We will be as objective as possible, hoping that our findings will in some small way push the state of audio forward another baby step.

And, if we do our work properly, we might hear a difference that helps readers make more pleasing amplifier choices here & there. Or not worry about so much about differences that do not exist.


----------



## Almadacr

kingnoob said:


> MY room has bad acoustics sadly, XT32 helped a lot though...



and it can be even better if you ad some room treatment .:T


----------



## ajinfla

dougc said:


> Why would I spend $9800 more on an amp when the difference cannot be proven? I would pay more money for quality customer service, locally built products, efficiency, and sad to say, but something that looks nice.


Bingo. Make no mistake, what Sonnie will end up demonstrating with the ABX box, is that there is little or no audible/perceivable difference in the soundfield _*within a given paradigm*_. That's it.
_Not_, that individuals will hear/"hear" no differences within _their_ systems, when listening casually at home. No reason to pooh-pooh anyone who prefers to use/own a $10k amp, or watch, or cables, or...anything that is subjectively pleasing. I doubt _any_ B&W 802 owner raced out to buy Infinity 360s after they were preferred by listeners in Harmans blind tests. Pleasure of ownership goes way beyond the soudwaves.
The only way there should be discord, is if *objective* claims of "better", etc. are made (and they often do!!!)
I make no apologies (or see any hypocrisy) with the $$$ amps and cables I use/own, any more so than for the old Pioneer HT receiver/zip wire. I simply make no claims of objective superiority, even if I prefer X subjectively.

cheers


----------



## ajinfla

Almadacr said:


> and it *can* be even better if you ad some room treatment .:T


Sure. Or worse.

cheers


----------



## chashint

ajinfla said:


> Bingo. Make no mistake, what Sonnie will end up demonstrating with the ABX box, is that there is little or no audible/perceivable difference in the soundfield _*within a given paradigm*_. That's it.
> _Not_, that individuals will hear/"hear" no differences within _their_ systems, when listening casually at home. No reason to pooh-pooh anyone who prefers to use/own a $10k amp, or watch, or cables, or...anything that is subjectively pleasing. I doubt _any_ B&W 802 owner raced out to buy Infinity 360s after they were preferred by listeners in Harmans blind tests. Pleasure of ownership goes way beyond the soudwaves.
> The only way there should be discord, is if *objective* claims of "better", etc. are made (and they often do!!!)
> I make no apologies (or see any hypocrisy) with the $$$ amps and cables I use/own, any more so than for the old Pioneer HT receiver/zip wire. I simply make no claims of objective superiority, even if I prefer X subjectively.
> 
> cheers


I am an objectivist to the bone, and I agree with you.
When an individual finds value in something then that something is worth it to that individual.


----------



## AudiocRaver

ajinfla said:


> "Poor" in the sense of method. Level matching of this sort, should be done with frequency dependent voltages at the speaker terminals. Acoustic measurements are insufficiently accurate, especially outside an anechoic space, where ambient noise levels will affect every measurement and create variability.
> Obviously the precision of the matching did not affect the outcome.
> 
> But maybe that's because the OSD (OCD?) is mid-fi (too cheap) and is a confounder, "masking" the differences.
> 
> Or because your cables are lying on the carpet  and there are static charges interacting with and modulating the induced magnetic fields, greatly confusing the electrons in the wires, creating indecision, unruly behavior and general unmusicality.
> Which would of course mask the differences we "know" are there.
> Since someone on the internet said so.
> 
> cheers


We have a much improved method of level matching going forward. It is a precision swept sine wave from 250 Hz to 4 kHz repeating 8 times per second. With an SPL meter physically locked in place for repeatability, C weighting, slow averaging, the sweep rate is fast enough that the meter reading in slow response mode is dead steady and does not vary, worst-case occasionally switching between two values 0.1 dB apart. A steady sine wave in any room can give varying results based on where you are standing / the minutest change in SPL meter location. The fast-swept sine gives all the advantages of pink noise (immunity to minor room acoustical changes, like whether or not you are breathing) with NO reading variations to have to guess at.

Sending it to you today, Sonnie.


----------



## Savjac

AudiocRaver said:


> Sonnie sure has a way of getting a conversation going, doesn't he?
> 
> I will throw in a few thoughts...
> 
> 
> *Being Objective*
> In subjective matters, like the ability of the human ear to perceive very subtle differences in sound, imagination can play a big role in the forming of our perceptions. This is not a new concept. There are vital questions to ask oneself: "_Can I trust these subjective impressions?_ _Did I make them up?_ _Is it possible that I imagined there to be a difference that does not actually exist?_"
> 
> Human imagination can be a wonderful thing. Sometimes its benefits from a little skepticism to keep it grounded in reality.
> 
> 
> When it comes to questions of one's ability to even hear this kind of fine detail reliably, believing it without proof is nothing more then a faith-based opinion.
> 
> Who does that leave? Could there be some fear of being proven wrong? That is not hard to conceive of. There are those who have a lot invested in "being right" about something that is unprovable.
> 
> And, if we do our work properly, we might hear a difference that helps readers make more pleasing amplifier choices here & there. Or not worry about so much about differences that do not exist.


Being objective in the case of things "Desired" is truly difficult. One can only make recommendations or presentations based upon our experiences to date as well as a million other details such as past experience, ancillary equipment, expectations and not the least of all, the human brain. I do not think that equipment, at this point in time, can tell me what I will and will not like. Yes it will provide a wonderful baseline of what a given product can do given the testing situation the product is being tested in.

I think the human ear/brain can decode many more things than we may give credit to. Especially what we as listeners will find enjoyable. We all own different pieces of equipment, that we as individuals feel bring us to a special place. How else do we explain so many Different types of gear that has been produced and purchased. If a piece of test equipment could determine item A operates perfectly and item B is somewhat less than stellar, then item A should be the choice of everyone, however, that does not occur. Just amongst the fine people here on this thread, there is no consensus of what is the best, pro amps, home audio amps, cd player, pre amps etc etc.

Again, just my opinion and yes I am open minded or so I thought. :innocent:


----------



## Sonnie

I have edited the first post, added another section with more comparisons and measurements.

I even included a short and shamefully unfair comparison between the Montis and A5. Ironic that I just typed that comment and as I sit here typing and listening to random music from my USB thumb drive in the HT room, up pops ZZ Ward singing _Put the Gun Down_. Sending out a dedication to Emotiva an Jon Lane. :sarcastic:


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## ajinfla

AudiocRaver said:


> We have a much improved method of level matching going forward. It is a precision swept sine wave from 250 Hz to 4 kHz repeating 8 times per second. With an SPL meter physically locked in place for repeatability, C weighting, slow averaging, the sweep rate is fast enough that the meter reading in slow response mode is dead steady and does not vary, worst-case occasionally switching between two values 0.1 dB apart. A steady sine wave in any room can give varying results based on where you are standing / the minutest change in SPL meter location. The fast-swept sine gives all the advantages of pink noise (immunity to minor room acoustical changes, like whether or not you are breathing) with NO reading variations to have to guess at.
> 
> Sending it to you today, Sonnie.


What I was suggesting eliminates (the variability of) acoustic measurement and requires only a (reasonably accurate) voltmeter.
Your method sounds more fun 

cheers


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## Sonnie

The Van Alstine ABX Test Box is supposed to level match, which will be nice.

Wayne probably knows, but how do you do the level matching with the voltmeter? I do have a nice Fluke meter here.

I would want to do both simply to see the frequency response match of the amps to make sure one amp is not coloring the sound in some way with the response. I am fine with a 1dB variance, but if some area is off by 3-4dB, then we are getting in that range where it could very well be noticeable and that difference alone could effect the comparison. I am thinking they will all be the same, but we won't know for sure unless we measure.


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## ajinfla

Sonnie said:


> Overall, I personally just plain feel better running the Emotiva amps for my main channels than I do the Behringers. I need to feel good about what I own and I fully understand this playing an important role in what we purchase.


Personally, I feel you just like glowing blue lights.

Not that there's anything wrong with that.

cheers


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## Tonto

Link not working


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## Sonnie

ajinfla said:


> Personally, I feel you just like glowing blue lights.
> 
> Not that there's anything wrong with that.
> 
> cheers


I do, I do! I prefer just the rail lights though... and not the five LED lights for each channel. I can turn off the rails, but not the five LEDs.




Tonto said:


> Link not working


Which of many thousands of links might you be referring too? :dontknow:


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## tonyvdb

AudiocRaver said:


> We have a much improved method of level matching going forward. It is a precision swept sine wave from 250 Hz to 4 kHz repeating 8 times per second. With an SPL meter physically locked in place for repeatability, C weighting, slow averaging, the sweep rate is fast enough that the meter reading in slow response mode is dead steady and does not vary, worst-case occasionally switching between two values 0.1 dB apart.


Just out of curiosity would band limited pink noise or even regular pink noise not be just as good?


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## AudiocRaver

Savjac said:


> Being objective in the case of things "Desired" is truly difficult. One can only make recommendations or presentations based upon our experiences to date as well as a million other details such as past experience, ancillary equipment, expectations and not the least of all, the human brain. I do not think that equipment, at this point in time, can tell me what I will and will not like. Yes it will provide a wonderful baseline of what a given product can do given the testing situation the product is being tested in.
> 
> I think the human ear/brain can decode many more things than we may give credit to. Especially what we as listeners will find enjoyable. We all own different pieces of equipment, that we as individuals feel bring us to a special place. How else do we explain so many Different types of gear that has been produced and purchased. If a piece of test equipment could determine item A operates perfectly and item B is somewhat less than stellar, then item A should be the choice of everyone, however, that does not occur. Just amongst the fine people here on this thread, there is no consensus of what is the best, pro amps, home audio amps, cd player, pre amps etc etc.


So true that preference can be due to many things. Some differences in sound are not easily categorized as "better" or "worse," just "different." Also, the brain can collect information (auditory and otherwise) over time, performing an integral function, presenting to the consciousness the final result as, simply, "I like this amplifier," while all the reasons might not be obvious for that listener.

Factors might include the way the volume knob feels, the shiny metal, the fact that a friend built it for you from scratch, a myriad of possible reasons to like/prefer one over another. _Sometimes_ a factor stands out that is universally agreed upon. All an evaluator can do is report her/his experience as clearly as possible and hope it is helpful to someone.



ajinfla said:


> What I was suggesting eliminates (the variability of) acoustic measurement and requires only a (reasonably accurate) voltmeter.
> Your method sounds more fun


No argument. The test signal mentioned was needed/is useful for other things, balancing speaker levels, etc, and is useful for level matching, too. We will take the opportunity to compare both methods.



Sonnie said:


> *I would want to do both simply to see the frequency response match of the amps to make sure one amp is not coloring the sound in some way with the response.* I am fine with a 1dB variance, but if some area is off by 3-4dB, then we are getting in that range where it could very well be noticeable and that difference alone could effect the comparison. I am thinking they will all be the same, but we won't know for sure unless we measure.


I like the idea of doing it both ways. If we see a difference, that alone will tell us that something needs looking at. It is reasonable to get within a fraction of a dB with sine (with voltmeter) or swept sine (with voltmeter and with SPL meter) signals, where even 1 dB matching is hard with an acoustically measured steady sine or with pink noise.


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## AudiocRaver

tonyvdb said:


> Just out of curiosity would band limited pink noise or even regular pink noise not be just as good?


With regular pink noise the SPL reading varies over about a 1 dB range and the operator has to mentally guess at the average of those readings, even when using the slow-averaging function of the SPL meter. Band limited pink noise (500 to 2 k) reduces the variation a lot, but it still varies (forget how much, seems like it was several tenths of a dB, maybe half a dB). The swept sine covers 4 full octaves (more is better here - it could easily be made to cover a broader range) and gives a rock-steady reading.

Another option is to use regular or band-limited pink noise and REW's RTA function with 16 or 32 averages and use the SPL reading on the RTA. This method would give a stable reading but with some wait time between readings.


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## tonyvdb

Interesting, I've never really noticed that there was any variation in the SPL with pink noise. I'm going to have to test that one out. :T


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## Sonnie

Look at it on the RTA in REW and you can see it fluctuate.


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## AudiocRaver

tonyvdb said:


> Interesting, I've never really noticed that there was any variation in the SPL with pink noise. I'm going to have to test that one out. :T


If your meter has a 1/10th dB digit, it will jump around quite a bit with pink noise.


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## erwinbel

What a great read this is, thanks everybody! Obviously, it is no news that all properly designed amps sound the same if they are not driven into clipping. The Audio Critic (Mr Peter Aczel) wrote about the issue years ago. The recording plus the speakers and how the room reacts to the speakers are about 99% of what determines the sound.

http://www.theaudiocritic.com/plog/

Speaking of speakers, as a firm believer that [a] active crossovers are superior to passive ones and * there is no substitute for cubic inches, I want to build five inConcert Miles for LCRS in our HT. If money was no object, I'd simply buy the B&W CT8. These cost €15,000 each including a dedicated crossover for each semi-active (mid+high use passive crossover) speaker. I am confident I can get at least 95% of that sonic result with 10% of the cost. The (fantastic) tweeter and both woofers can be had for about €1,000 (cheapest purchase is in Spain where Beyma is resided)

Here's atledreier's build of the Miles:
http://www.hometheatershack.com/forums/diy-speakers/43341-tangen-avdesign-inconcert-miles.html

I'd use the miniDSP 10x10 Hd for crossover since atledreier recommends it. I read about the miniDSP and it doesn't seem very difficult to operate it. Since the Miles is a two-way design, I'd need a total of 10 amp channels. I prefer XLR connections. The Miles is very efficient (101 dB) although the woofers are rated for 800 Watt (Beyma TPL150H tweeter 80 Watt). 

Which amps would be recommended? These will be set in the room.*


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## Savjac

Merry Christmas Friends. May you and yours delight in ever second that passes !!!!!


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## Mechsmoto

Sonnie said:


> Just tried it... actually the EP2500 is quieter than the XPR-5... but neither can I notice unless I get my ear right next to the speaker. I also have a low hum with the XPR that is not there with the Behringer. Now that is going to drive me crazy.


Sonnie,

Maybe this is the "hum" I was referring to in my xpa5 thread?!?(it's not a normal ground loop kind of sound--almost like the transformer noise of something.... If you stick your face literally on the front of the amp itself, you will here the identical hum) I'd be very interested to see what you find out?! Does your xpr5 have a true- 3 prong plug?!?.. meaning, are there 3 prongs where the plug meets the back of the amp?!? 

If not, disconnect power and all sources from your pre amp. Run your five speakers from xpr5 like normal.... i used to get zero hum... pure hiss if only speakers were attached. Now, attach one Interconnect... and listen very closely to your center channel (this was the easiest speaker for me to identify it on). Should be no hum... only hiss. Now attach the second Interconnect(still nothing else attached to the preamp- not even power).... The hum should now be audible... attaching the remaining Interconnects will make it slightly more audible. Adjusting the volume on the preamp will have zero affect--- the hum should remain constant regardless. 

Iiiiiiiiiiiffffffff Im right, once you've verified this, will will be time to call Lonnie.


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## Tonto

Sonnie wrote:



> Which of many thousands of links might you be referring too?


Sorry, I'm at work & the filters are not letting me access a link. I'll try when I get home. It's a link to some "brain games" that truly are amazing. Just when you are *100% sure *of something...your *100% wrong*.

It's why these threads elicit such passionate responces. We really do believe...which is ok, but facts have to be accknowledged as just that. Amps don't make a difference when the playing field is level.

What we "like" combined with our "budget," has to be the decision points in the purchase.


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## Sonnie

Mechsmoto said:


> Sonnie,
> 
> Maybe this is the "hum" I was referring to in my xpa5 thread?!?(it's not a normal ground loop kind of sound--almost like the transformer noise of something.... If you stick your face literally on the front of the amp itself, you will here the identical hum) I'd be very interested to see what you find out?! Does your xpr5 have a true- 3 prong plug?!?.. meaning, are there 3 prongs where the plug meets the back of the amp?!?
> 
> If not, disconnect power and all sources from your pre amp. Run your five speakers from xpr5 like normal.... i used to get zero hum... pure hiss if only speakers were attached. Now, attach one Interconnect... and listen very closely to your center channel (this was the easiest speaker for me to identify it on). Should be no hum... only hiss. Now attach the second Interconnect(still nothing else attached to the preamp- not even power).... The hum should now be audible... attaching the remaining Interconnects will make it slightly more audible. Adjusting the volume on the preamp will have zero affect--- the hum should remain constant regardless.
> 
> Iiiiiiiiiiiffffffff Im right, once you've verified this, will will be time to call Lonnie.


I got all the switching gear out of the way and cleaned up my wiring behind my cabinet, which I had not done since swapping out gear and moving some stuff around... and it was then gone. Yet later, it seems to have come back, but my brother and I were about to watch a movie, so I did not take time to worry about it. I will investigate closer a bit later. My XPR has a grounded 20 amp power cord.


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## Mechsmoto

I should have known you'd have it all under control!!!!.. just wanted to offer any help I could!!! I only mentioned it, because in my case, it wasn't noticeable at first.. but once you picked up on it... "frustrating" doesn't even come close!!! Best of luck!! Take care!


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## Sonnie

Apparently it was the balanced and/or analog connection from the OPPO 105 to the Onkyo 5509. When I switched from the 105 HDMI output to Balanced output, I could hear it, although it was faint and I had to have my ear next to the speaker. My wife could probably hear it in the other room with her super woman ears. I tried switching over to RCA cables, but it was still there. Then I decided to try an Optical cable I have, it disappeared. I am not even sure why I have two separate inputs to separate Blu-ray movies from music. I was thinking it was so that I could switch off Audyssey when listening to music, but using Pure Audio takes care of that. I may as well just stick with using HDMI. I can't hear a difference from HDMI Pure Audio to Balanced, RCA, or Optical with Pure Audio.


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## Tonto

Well it must be a problem with the link, doesn't copy from home either. I did find another site that has some interesting illusions as well, just not as good as this one. 

This one featured a circle of green dots.
One of the dots changed to pink, then the next one changed to pink, then the next & so on.
It make it look like the pink dot was traveling aroung the entire circle.
As you stared at it, all the green dots disappeared, it you looked back to them they reappeared!

Anyway, here's another link that shows how our brain just makes stuff up to our dismay.

http://www.slideshare.net/code102/the-human-brain-its-tricks-us-presentation

We all know that seeing is believing!


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## johnplayerson

There are in fact differences. The higher the signal to noise ratio an amplifier delivers, gives a much deeper and spacious clean sound. This combined with a a source that is not compromising that signal to noise spec, will indeed make better sound. I have not heard anything better than my Asus Xonar STX 124 db analogue out card. I use this almost exclusively now, as it sound better than any cd player I have hooked up, and i have used yamaha pioneer, sony, and phillips for CD. Therefore one cannot argue the higher the signal to noise the better the amplifier will produce sound. 

Further Some amplifiers are designed with different components. I have personally used amplifiers that completely lack in producing deep low end, and of course this is more pronounced with subwoofer use. Old school amplifiers with huge reservoir caps will produce better subwoofer base. Again with just regular speakers the better designed bass amp may not make a difference as the speaker will not require as much output. 

While most amplifiers on basic speakers will sound very much the same, its like someone said before, .... Your not going to hear the huge difference playing your Asus Xonar STX card on your built in pc monitor speakers. You need to be using something that will test the amplifier to the full extremes. 

If you want to hear a great sound card put the Xonar stx in your computer and run the analogue out to your CD or MD in on your reciever or preamp, and then start thinking about testing your amplifiers again running the stx card as the source.

Another amplifier specification is the frequency response range , usually stated at 5 hz to 50000hz etc. These upper and lower specs are usually the half power points of the amplifier. A 500 watt amp will be 250 watts at 5hz and 250 watts at 50000 hz etc. There are many amplifiers with less range here, the main difference being in the low spec as you are not likely to hear 40000 hz, but an amplifiers ability to reproduce 5 to 30 hz with ease is important and will make a big difference at high output levels bass wise. Nothing like feeling and hearing nice smooth low end. Again you will not hear the difference in the better bass amplifier, unless your using high output subwoofers which will test the amplifier fully in this extremely narrow range of spectrum. 

If you want a good example of a really poor bass amplifier try the marathon ma 5050


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## Sonnie

johnplayerson said:


> There are in fact differences.


To clarify, you not not referencing the amps that are the subject of this thread... the Emotiva XPR-5 vs Behringer EP2500. 

I assume by "spacious" you mean less background noise, which is turn would create a more spacious effect during soft passages or during the silent parts of the music. What do you mean _exactly_ by "deeper"? Deeper bass?

If signal to noise ratio is important to you, check out the OPPO 105 at 130dB, which is what we are using here for comparisons. The Onkyo 5509 preamp runs at about 110dB and the Emotiva XPR at about 109dB, but it wasn't any more deeper or spacious (regardless of how you define those) than the EP2500 at 100dB. As a matter of fact, we could not hear any differences at all, period. We are also using Paradigm speakers as well as MartinLogan Montis... I suspect better than most PC monitor speakers, at least any I have heard.

You get to a point of diminishing returns (audible) when you reach a certain signal to noise ratio. Most of the modern day amps are going to be pretty good in that spec. Some of the older amps may have some noise with them. I want to say the Crown we will test has a bit of noise, so it will be interesting to see if the other amps are "deeper and spacious" than it, depending on exactly how you define those terms. I will give them "cleaner" before even listening, because when we had the Crown hooked up, IIRC, I could hear the noise floor pretty good. Whether that translates to your defined "deeper and spacious" remains to be heard.

I agree there are probably some older amps that have the lower frequencies rolled off, but that is something we can measure and verify during testing. With most music it won't be noticeable since most of what we are listening to does not have much information in the really low range. You might notice it on movies with information below 20Hz, unless you got an amp that is rolling the frequencies off at 30Hz, but even most of the older ones are flat to 20Hz. Not saying all, but I suspect most.


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## AudiocRaver

Just for kicks, I could create a couple A-B test loops with elevated noise floor, see at what level we can hear it with consistency at our next listening weekend.


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## Sonnie

Good idea... :T


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## tonyvdb

Do you guys think that the Behringer EP2500 would over time get nosy as the electronics age? The build quality of their amps in general are not as good as an Emotiva or the likes of QSC or even Yamaha and failure is much higher. There is a reason you hardy ever see them used in tour rigs used in big productions.
I have a friend who runs the rental and production devision at AXE music here and he says they would never use them for anything because they have longevity issues.


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## Sonnie

I suppose there is a possibility. I have owned mine for quite a number of years, but there is one out of the four that has a bad channel. Two of them I purchased used, so not sure how old they were when I got them. They have certainly been popular for sub amps. 

I know the pros use them a lot, cause they are talked about frequently in the pro forums. I have read several instances of them being used for years on end with no issues. I have also read where people say they would never own one. Yet, I see the same exact things being said about Crown and QSC. It just all depends on who you talk to.


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## tonyvdb

Yes very popular as sub amps and I think they are the very best bargain out there for that use. I just wonder how many people use them for full range and moreso using them for a long time.
If you do a test make sure you do it with speakers that are efficient (above 92db) I think the noise levels may be much more noticeable from the Behringer. My thoughts anyhow.


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## AudiocRaver

Interesting. I just posted in another thread about Behringer quality/reliability.

In a discussion with a Behringer factory rep recently, it was explained that their products are all built in their own factory in China, so they are able to control quality closely, and it has been getting steadily better in recent years as a result. Their specs are respectable. As for longevity, having been inside lots of pro and non-pro equipment over the years (including Behringer), I would say their "heavy duty-ness" level in general is not as tough as brands that you see on tour and on the road. I can think of no reason in a home theater or studio or permanent installation where they are well treated (sufficient cooling, clean power, etc.) and not knocked around why they would not have a long, reliable service life. There is also no engineering reason for components in a less expensive brand "getting noisy" earlier than another. This is related to component failure rates, which approach 100K hours under specified conditions for most component families used in AV equipment.


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## Sonnie

We have already tested the EP2500 with the Paradigm Studio 60, which is 92dB sensitivity and we could not hear any noise difference. The EP2500 SNR is 100dB, which is very respectable. I would have no issues using it full range.


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## Savjac

I am sooo confused with all the cool information that I think I need more brain :scratchhead:

The one thing that I am getting here is I need another job so I can afford the bigger Martin Logans :spend:

Maybe I am getting the wrong message...:innocent:


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## Tonto

Jack wrote:



> The one thing that I am getting here is I need another job so I can afford the bigger Martin Logans


Or you could just wait a couple of years till Sonnie upgrades again & sells his cheap!
Ok, Ok, So maybe I am a little jealous!

My name is Tonto & I am an audioholic!!!


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## tonyvdb

Tonto said:


> I am an audioholic!!!


Aren't we all :dumbcrazy:


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## ajinfla

tonyvdb said:


> Do you guys think that the Behringer EP2500 would over time get nosy as the electronics age?


Well if it starts poking around the equipment rack asking why you have Emotiva and other brands, I'd say yes. 
Otherwise, I wouldn't worry much about component deterioration/noise because that should be a decades type thing, given home audio usage. Regarding noise mentioned previously, I would suspect that has far more to do with gain structure than anything else. Pro equipment + home audio newb usually = disaster.



tonyvdb said:


> I have a friend who runs the rental and production devision at AXE music here and he says they would never use them for anything because they have longevity issues.


No doubt the B stuff is cheap mass produced Chinese...but then again so is a lot of other stuff that can be trouble free for decades...or not.
Don't own a B amp, do have a DCX (numerous issues), DEQ, FBQ, SRC (zero issues) for several years.

Reliability and the glaring street cred issues aside, really no reason to avoid the EP full range.
I'll leave with an old, but still very relevant article by Douglas Self, regarding "subjective" evaluation of amps, etc. 

cheers


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## Savjac

Pulled this out of storage yesterday (The Garage) took off the packing material from our move and said, voila, instant amp challenge. Alas after I played with it, powered it on and then looked inside, there is no way I will connect my stuff to it. There is no place to store any music in there.....no awesome capacitance, and it would probably bring the rest of the system down :innocent:

Oh and the rack ears come off too, almost perfect...for a system in the garage. It is also designed and manufactured in the good ole USofA.


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## Sonnie

That sure doesn't seem like much power for a pro amp.


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## Savjac

In today's world yes it seems a bit anemic, but 10 years ago or more not as much. It seems watts like computer storage has gotten cheaper and more efficient. I also think companies like Behringer have really changed the face of the market; price and quality wise by being able to do pretty much everything in house in China where they can really control every bit of design to manufacture in one place. 

I am not sure companies like Peavy could even come close to the tolerances, component quality, build quality that Behringer can today.

This amp would not pass your sound test.


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## AudiocRaver

Savjac said:


> This amp would not pass your sound test.


Are you SURE?

I like big power supply caps as much as the next fellow, but absent any higher-volume or big-bass power-hungry passages in the music, a huge power supply reservoir might not be needed. It might sound just fine. One has to be sure one does not create a bias ahead of time just by a look inside a piece of equipment that leads to them being convinced it sounds bad. Is that not the case?


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## nwhitta

Just caught up with this thread, although it was started some time ago.
I note that the original poster compared the EP2500 with the Emotiva XP-5 and reported no sonic differences between the amps, but he did notice a huge difference between different speakers; ML Montis and A.N.Other.
His experience mirrors mine. I have a pair of EP4000 amps (with silent fan mod) bi-amping a pair of Sanders Model 11 hybrid electrostatics (very similar to the Montis). I am wowed by the sound quality. I was introduced to the beguiling attraction of electrostatics by listening to the Montis driven by both a MacIntosh 275 tube amp and a Devialet D200. I have not heard my set-up side by side with that Montis set-up but both are stunning.
I am loath to say that there is no difference between comparable power amps, but the differences are truly very small compared with speakers. However having sufficient power is absolutely crucial. An amp may misbehave and sound unruly when it clips (due to having insufficient power to drive the musical peaks). This typically introduces a harsh grainy sound before it really misbehaves. Even music played at normal levels requires large power reserves to hit musical peaks which may be 12-15dB above the average level. Power requirements double with every 3dB increase in volume so an increase of 15dB requires 32x more power from the amp. When my wife plays the Hallelujah chorus at concert levels in our lounge, even the 650W (as tested into 4 ohms) EP4000 illuminates the clipping lights when the sopranos hit their straps. 
My belief is that most sonic differences heard between amps are caused by different ways in which amps respond to clipping. A good big-un will always beat a good little-un is a time-honoured phrase from the world of boxing and it also applies to power amps.


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