# EP2500 on fronts...



## DisTreSs (Sep 27, 2008)

Just a quick question:

I was wondering, in anticipation of my first sub build, could I go ahead and get a EP2500 -saw one used for 225€ which seems reasonable to me... isn't it?- and hook it up to my mains?
They're B&W N803s so I'm not willing to take any chances.
The amp is 2x450W at 8Ohm so plenty of grunt still but I suppose THD will be higher than more conventional speaker amps?

Sorry about opening a new thread on this, but my responses to my own n00b DIY thread are still pending approval and I need to know this rather sooner than later


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## tcarcio (Jun 27, 2007)

Absolutley, I run pro amps on my HT and it will be fine and should sound great. Just be carefull not to overdrive and distort the signal and you will be happy, I was.:yay:


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## tonyvdb (Sep 5, 2007)

Running an external amp on the mains is always a good idea, it relieves the load on the receivers power supply so it can drive the other channels better. However in your case 450watts is more power then the 803's can handle so be careful how hard you drive them.


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## DisTreSs (Sep 27, 2008)

Thx very much, both of you, for your replies!

I realise 450W is a lot at 8Ohm, but I am even more worried (even though B&W offer pretty stable resistance values) that at one point the amp will only get a load smaller than 4Ohms which would powerslam my speakers with even more serious wattage....:hide:

Still, if I don't dial up too much I guess I'll be fine.

So is 225€ (300 USD, 176GBP) a reasonable second-hand price for one of these??

(Yeaaay, I can post directly now!!!  Will have to rewrite the answers I gave in my original thread that didn't get posted though  )


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## tonyvdb (Sep 5, 2007)

The 803's are very nice speakers (I'm jealous) I would not worry about it too much. simply set your Crossover high enough that they dont get anything below 30Hz any you'll be fine.
The price seems reasonable, Go for it!


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## DisTreSs (Sep 27, 2008)

tonyvdb said:


> The 803's are very nice speakers (I'm jealous) I would not worry about it too much. simply set your Crossover high enough that they dont get anything below 30Hz any you'll be fine.
> The price seems reasonable, Go for it!


Thx again Tony!!

The N803's came at a price that's for sure...
Till this day (since 2001) I haven't had a chance to upgrade anything in the HT because of them, even though they were discounted demo models...
My surround speakers are still old pioneer speakers from my very first 'HiFi'-set way back when... :jiggy:

But hey, it'll be a cold day in hell before anyone pries these babies from my cold dead fingers :boxer: They've proven to be worth every penny...

The sub I'm planning on is actually my first upgrade audio-wise in a looong time so I'm hoping for some great results...
I've actually tried posting in my other topic again, but still nothing.... grrrrrr.... what gives?
How come I can post here but not there...


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## DisTreSs (Sep 27, 2008)

Well, seeing as I still can't post in the other thread thought I'd post a question I had about the sub in here... :devil:

Would a combination of an EP2500 with a Tempest-X and a sizeable bit of sonotube (not LLT but still large enough) beat the pants of an eD A5-350 with 550W amp or an MFW15 and such?

That's all I really want: assemble a sub that performs like the ones in the US for the price that you guys pay in the US


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## tcarcio (Jun 27, 2007)

Well I owned the A5-350 and although it is a nice sub I was a bit dissapointed. I had to wait quite awhile for the sub and I think that maybe my anticapation made me feel that it should have been better. I also had problems with the driver and the amp. They did fix those problems for me but in the end I sold it. I don't know enough about the Tempest but I run the EP2500 with a sealed sub and I am very happy with the sound. I stuck with ED for the driver and used the 130v.2 in a small enclosure. I think you would be fine with what you are thinking of for the amp and maybe someone with more experience with the tempest will chime in. Good luck.:T


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## DisTreSs (Sep 27, 2008)

thx very much for your reply!
I was actually looking into importing an a5-350 which is why I keep using it as my base of comparison at least price-wise since I haven't heard it of course.

I am aware that eD suffered a setback with the amps, but all should be well now. I'm surprised to hear that, even after it got fixed, you think it didn't live up to expectations. Even more surprised though that you felt more happy with the a sealed 12" with limited XMax compared to the ported 15" whopper 
Maybe you like the tight sound of sealed better?
It's good to hear the EP2500 has so much on offer though.

Anyway, I calculated that for 1000$ I could get the A5-350 delivered at my doorstep. But if I'm able to make a sub that rivals with that for 850$ (amp, driver, tube, MDF and parts), I'd be more than thrilled about it! I'll even pay as much as 1000$ to have a DIY sub if I know it'll blow the A5 or MFW out of the water 
The lady of the house on the other hand seems to prefer challenging me to keeping the budget the same as you guys pay in the US... 650$.... addle:
I'm sticking to 850$ though as being more realistic


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## tcarcio (Jun 27, 2007)

DisTreSs said:


> thx very much for your reply!
> I was actually looking into importing an a5-350 which is why I keep using it as my base of comparison at least price-wise since I haven't heard it of course.
> 
> I am aware that eD suffered a setback with the amps, but all should be well now. I'm surprised to hear that, even after it got fixed, you think it didn't live up to expectations. Even more surprised though that you felt more happy with the a sealed 12" with limited XMax compared to the ported 15" whopper
> ...


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## DisTreSs (Sep 27, 2008)

tcarcio said:


> I said that I was happy with the sound but I am adding a second sealed sub useing the Shivax 12'' in a little bigger box. I think then I will be more happy......:yes:


hehe no doubt! :T


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## DisTreSs (Sep 27, 2008)

So I just got off the phone with the guy selling his EP2500's and I asked him about trying out the amp on my B&W's first and if I liked it I would come and get a second one for the subwoofer...
But he was adamant to NOT hook this puppy up to my B&W's cause he feared they would get destroyed.

Apparantly they hooked up a similar amp up to a hifi speaker once and after five minutes of playing, the woofer was hot as a mother**** (his words... but in dutch... :innocent.
He will now not sell me a second one as he firmly believes that long-term (short term should be fine) exposure of my B&W's to this amp would overheat the speakers and cause permanent damage....

Purely on specs he is right of course: this amp delivers [email protected] and my speakers are only rated for 250W...
But I thought that if I dialed in the amp conservatively I would be fine, but he seems to think this won't be the case....

Now what do I do??? Will I be fine and do I get the second one despite all his advice (it's not like he has anything to gain by saying this, on the contrary) or not??? :dizzy::dizzy::dizzy:


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## tonyvdb (Sep 5, 2007)

He has no idea what he is talking about, unless the amp is not rated to drive speakers with 4ohms I wouldn't worry about it. It is just like I said earlier just make sure you have the crossover in your receiver set to be above the lowest frequency response that your B&W speakers can handle and you will be fine. Just like you said just keep the levels reasonable. Your B&Ws can easily reach reference witch would be about 50% of the amps maximum output. So if you set the amp at 50% then you should be just fine.
I should add that because your speakers can go as low as 3.2 ohms depending on the level you could be theoretically getting allot more than 450watts out of the amp but this also causes more heat generation in the amp.


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## thxgoon (Feb 23, 2007)

Yeah, what Tony said. It doesn't matter how much power the amp has, it will only output enough power for the given listening level. IOW, 85db with a 10 watt amp will have the exact same power to the speakers as 85db with a 1,000 watt amp. Nothing to worry about, just don't crank it REALLY loud


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## DisTreSs (Sep 27, 2008)

thx for the insights guys.
I'm picking up one amp tomorrow since I will be needing it anyway for the sub.
Talked him down to 268$ btw  

Since I won't have my sub finished straight away of course, I'll have plenty of time (relatively speaking...) of testing out the amp on the B&W's as per your comforting words :yes:. I'll carefully dial it up from 0 to see how they react with different sources. If all stays well (it just has to as I would kick myself in the a$$ the rest of my life if it doesn't...) then I'll just phone him up again to buy a second one. He has 5 on sale from a rack he isn't using anymore and I'm guessing they won't all be gone the day after tomorrow 

Tony, my B&W's go down to 35Hz -3 dB by the way. 28Hz at -6 even :demon: so setting the amps X-over to 40-ish should do the trick I suppose since it's probably not an absolute Xover but will roll off gradually.
You'll probably understand why up till now my need for a sub was present yet nog overwhelmingly so 

Thxgoon, you raise an interesting point but it also got me more confused: If my Denon 3801 receiver that only puts out [email protected] can get my B&W's to reference, then why would I even need the other amp...
I've always wanted to take some of the load of the Denon because frankly, having 7 amps in there I can't believe that all amps are getting what is needed all the time from the power supply, but leaving this out of the equation, what else does the added amp do?
I mean, you always hear people talk about headroom, but if all I am doing is dialing down the EP2500 to the level of the Denon, then why the need for a more powerfull amp?


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## thxgoon (Feb 23, 2007)

DisTreSs said:


> Thxgoon, you raise an interesting point but it also got me more confused: If my Denon 3801 receiver that only puts out [email protected] can get my B&W's to reference, then why would I even need the other amp...
> I've always wanted to take some of the load of the Denon because frankly, having 7 amps in there I can't believe that all amps are getting what is needed all the time from the power supply, but leaving this out of the equation, what else does the added amp do?
> I mean, you always hear people talk about headroom, but if all I am doing is dialing down the EP2500 to the level of the Denon, then why the need for a more powerfull amp?


You are asking the right questions! The need for more power, or for external amplification is one of the most hotly debated topics in consumer electronics. In theory, any amp operating with negligible distortion within it's design constraints will sound exactly the same as another amp under the same conditions. There are some other tricky electonic interactions between the amp and the speaker that could render sonic differences, but these are rare and hard to test. Since you already have an amp coming, do the best thing and decide for yourself. If you don't hear a difference, don't waste your money :bigsmile:


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## tonyvdb (Sep 5, 2007)

DisTreSs said:


> Tony, my B&W's go down to 35Hz -3 dB by the way. 28Hz at -6 even :demon: so setting the amps X-over to 40-ish should do the trick I suppose since it's probably not an absolute Xover but will roll off gradually.
> You'll probably understand why up till now my need for a sub was present yet nog overwhelmingly so


Fully understand, My Mission 765's go down to 36Hz and Ive pushed them hard from time to time (way over reference) I've had them as loud as 110db with music :bigsmile: and have never had an issue. I run an external amp as well thats actualy a 4 channel amp bridged to two channels at 240watts at 8ohms and Im running 4ohm speakers so I am somewhat in the same boat as you.



> Thxgoon, you raise an interesting point but it also got me more confused: If my Denon 3801 receiver that only puts out [email protected] can get my B&W's to reference, then why would I even need the other amp...
> I've always wanted to take some of the load of the Denon because frankly, having 7 amps in there I can't believe that all amps are getting what is needed all the time from the power supply, but leaving this out of the equation, what else does the added amp do?
> I mean, you always hear people talk about headroom, but if all I am doing is dialing down the EP2500 to the level of the Denon, then why the need for a more powerfull amp?


This is easy to explain, Receivers are all rated the same way for the most part. Sadly some companies like to fudge the numbers a bit so they look better on paper.
When receivers are rated, they rate them at full output on TWO channels only and usually only for a few seconds at best. The biggest problem is that receivers dont have a big enough power supply to drive all 7 channels at the so called full rated power output even though the amplifier section can probably do it. Onkyo is they only affordable receiver (805 and up) that actually has a large enough PS to do the job fairly well. 
This is why so many of us choose to power the main front channels with an external amp. as this frees up the receivers PS to do a better job with the rest of the channels.


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## thxgoon (Feb 23, 2007)

tonyvdb said:


> When receivers are rated, they rate them at full output on TWO channels only and usually only for a few seconds at best. The biggest problem is that receivers dont have a big enough power supply to drive all 7 channels at the so called full rated power output even though the amplifier section can probably do it.



This is true but it's not necessarily indicitive of any real world performance. With the OP's B&W's (90db efficient), reference levels are reached with only about 35 watts. Most decent recievers are capable of 35X7 (including his Denon). THX specifies (or was it UL?) an amplifier be capable of 10% output over an 8 hour period without distortion or thermal shutdown. This is what they consider a tourture test and if you think about it for a 150 watt receiver, that's 15 watts, or 101db with the OP's B&W's, in all channels for 8 hours. I can't imagine exceeding that in my house :bigsmile:


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## tonyvdb (Sep 5, 2007)

thxgoon said:


> Most decent recievers are capable of 35X7 (including his Denon). THX specifies (or was it UL?) an amplifier be capable of 10% output over an 8 hour period without distortion or thermal shutdown. This is what they consider a tourture test and if you think about it for a 150 watt receiver, that's 15 watts, or 101db with the OP's B&W's, in all channels for 8 hours. I can't imagine exceeding that in my house :bigsmile:


Good points, Isn't the rating also "peak" output not normal output. because even though 35watts is sufficient there would still be peaks of much higher levels that that? This is why I like how Harmon Kardon rates there receivers as they rate them much more "true" output than any of the others.


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## DisTreSs (Sep 27, 2008)

thxgoon said:


> You are asking the right questions! The need for more power, or for external amplification is one of the most hotly debated topics in consumer electronics. In theory, any amp operating with negligible distortion within it's design constraints will sound exactly the same as another amp under the same conditions. There are some other tricky electonic interactions between the amp and the speaker that could render sonic differences, but these are rare and hard to test. Since you already have an amp coming, do the best thing and decide for yourself. If you don't hear a difference, don't waste your money :bigsmile:


I definitely do not want to get into discussions of 'warmer' and 'harsh' sounding amps and will just trust my ears.:T
I've bumped into too many of those threads throughout the years and have never found a clearcut consensus 

Myself, I've never had anything to compare to so I'm not one to speak much on the subject. The moment I hooked up my Denon to my B&W's I knew that they would bring me much joy in the years to come, so I never bothered A/B-ing anything else before putting the money on the table for the Denon.
After testing an Onkyo a friend of mine brought over earlier this year (less wattage btw) I can say that it didn't make much difference... Given the exact same power, I doubt I would be able to tell any at all so I'm glad I made my decision that easily back in the day.

I'll let you know how it turns out tomorrow and if the 'headroom' from the new amp will yield any differences.

Theoretically though, I was thinking that eventually having the 2500 about halfway would deliver the B&W's maximum [email protected] If I was to be able to have my Denons pre-outs volume level altered (still have to check on that...) and lower or higher it untill my test tone on the SPLmeter reads 75 at the listening position, that will be the way to go no? It is the only way that I can see that I will effectively have an advantage over simply using the Denons amp.
This as opposed to having the 2500 dialed down some more and having to turn up the signal on the preout...

Oops, there I go again :dizzy::dumbcrazy::dizzy:


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## DisTreSs (Sep 27, 2008)

thxgoon said:


> This is true but it's not necessarily indicitive of any real world performance. With the OP's B&W's (90db efficient), reference levels are reached with only about 35 watts. Most decent recievers are capable of 35X7 (including his Denon). THX specifies (or was it UL?) an amplifier be capable of 10% output over an 8 hour period without distortion or thermal shutdown. This is what they consider a tourture test and if you think about it for a 150 watt receiver, that's 15 watts, or 101db with the OP's B&W's, in all channels for 8 hours. I can't imagine exceeding that in my house :bigsmile:


After reading this, I think I'm getting it al wrong...
Or is the 101dB measured at 1m distance from the speaker at that point?


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## thxgoon (Feb 23, 2007)

tonyvdb said:


> Good points, Isn't the rating also "peak" output not normal output. because even though 35watts is sufficient there would still be peaks of much higher levels that that? This is why I like how Harmon Kardon rates there receivers as they rate them much more "true" output than any of the others.


Yes, but this is where things get confusing. 35 watts is what's required to play 105 db which is the brick wall max output on movie soundtracks (unless you're volume is set above reference), so technically 35 watts is the required peak output.



> After reading this, I think I'm getting it al wrong...
> Or is the 101dB measured at 1m distance from the speaker at that point?


No, you're correct. These numbers would be at the 1m point from the speaker but in full space (iirc?), so you gain about 6db of efficiency back when the speakers are placed in a room (half space). I took some measurements of my own system a while back and found that I lost about 6db from the 1m point to the couch, so things kind of even out.

I am curious of your findings though. There has been much debate on the issue of using pro amps in a home environment and on the power issue. Some first hand experience on a nice set of speakers like yours would be great!


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## ScruffyHT (Sep 23, 2008)

Here is one explanation to your question

http://www.axiomaudio.com/tips_separates_electronics.html


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## SteveCallas (Apr 29, 2006)

Couple things - first, a pro amp will be fine in terms of powering your main speakers. You can't "overpower" them in the sense that they are rated for 225 watts and the amp can produce 450 watts, as the amp will only deliver x amount of watts to reach a certain output level. So however loud you were listening before with your receiver required x amount of watts, and now that same x will be asked from the amp.

What I would be concerned about is the fan noise from the amp as well as the somewhat low input sensitivity. The fan you will need to mod, and as for the sensitivity, you will probably need to turn the R and L speaker preout levels up pretty high. The question then becomes which chain will create more distortion, the receiver with high preout levels and a high power, low distortion amp, or the receiver with speaker levels low and a low distortion receiver amp at most listening levels. You'll have to test and see (or should I say hear?)


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## DisTreSs (Sep 27, 2008)

Well as you can imagine, I set the amp straight to work once I got home 

I've been tinkering with it for about an hour and below you can find my preliminary findings.
I'll start off with the set-up though:
I just played a simple whitenoise test tone from my receiver with volume setting to 0: with the amps halfway, I still had to dial up the channel level on my receiver for it to reach 75dB which to me indicates that the pre-outs lose some of the signal strength. The reason I decided to put the amps at the halfway point was that I guessed that [email protected] divided by 2 = 225W which is still safely enough within the boundries for my speakers. As long as the increase is pretty linear with those gain knobs, which it probably is, I should be ok.


The result then was quite surprising in that the sound pressure from the speakers, when playing source material that I'm used to hearing and keeping in mind that the fronts were calibrated at 75dB just as before, was now much greater than it ever was.
However, with it came the fact that mid and upper frequencies were now much more transparant which I initially liked but after some time I felt it was a bit too much and maybe overly bright.
I would not attribute this entirely to the amp though as the room I am in now has still way to much reflection to my taste and maybe this is why this got overemphasized.

When I dialed down the amps and increased the receiver's volume passed 0, the brightness seemed to be tamed somewhat but in truth I have no idea if I compensated the decrease in amp level enough by the increase of volume level on the receiver.

Anyway, take my findings so far for what they are worth as I had no time to AB properly tonight and will be conducting further experiments later. I find it strange though that theoretically the amps should be delivering the same power as the receiver at 75dB (as per the theory described in previous posts) but that they would sound much more 'loud' with source material.

If you guys have any tests you would like to see me conduct that are of a less subjective nature, please let me know and I'll see what I can do.

PS: I might have to transfer this thread as it kinda lost its link to the subwoofer aspect no?


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## SteveCallas (Apr 29, 2006)

Setting the amp's attenuation controls halfway does not limit the output power to half. The amp can output full rated power even with the knobs nearly all the way down. Your speakers have a fixed sensitivity, and it will always require x amount of watts to achieve y level of spl. It doesn't matter what amplifier you use, if you are trying to achieve 75db at your seat, it was always require the same amount of watts. Because of this, and because you are having to turn the preout gains up, I would set the attenuation controls on the amp up higher and bring the preout levels down a bit.

Also, the EP2500 is pretty flat on the top end, so the amp is not causing your speakers to sound brighter.


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## thxgoon (Feb 23, 2007)

DisTreSs said:


> PS: I might have to transfer this thread as it kinda lost its link to the subwoofer aspect no?


I moved the thread to Home Theater Components.

Thanks for the first impressions! I'd follow Steve's advice and set the gains on the amp such that your level settings in the receiver are at 0. This will rule out any difference in sound as a consequence of pre amp gain. Also, try some measurements and see if 'louder' is actually louder or if it is perceived. Do you have REW installed? It would be neat to see some sweeps on one amp vs the other. Come to think of it... maybe I'll try that :bigsmile:


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## DisTreSs (Sep 27, 2008)

SteveCallas said:


> Setting the amp's attenuation controls halfway does not limit the output power to half. The amp can output full rated power even with the knobs nearly all the way down. Your speakers have a fixed sensitivity, and it will always require x amount of watts to achieve y level of spl. It doesn't matter what amplifier you use, if you are trying to achieve 75db at your seat, it was always require the same amount of watts. Because of this, and because you are having to turn the preout gains up, I would set the attenuation controls on the amp up higher and bring the preout levels down a bit.
> 
> Also, the EP2500 is pretty flat on the top end, so the amp is not causing your speakers to sound brighter.


Oh , so the gain control is actually not regulating voltage supply to the amp and therefore not telling the amps how many watts to deliver...?? This is a whole new way of looking at things for me but please forgive me since I'm still kinda new to it 

Had I known this beforehand, I doubt I would've hooked up the speakers to it 
But now that I have, and everything is still working, I might as well continue.
I suppose the theory that the same amount of watts are drawn by the speakers to achieve 75dB at the 0-setting, is a valid one then 
Along those lines, it would indeed be better to hook up something like the EP2500 rather than anything else since an amp with limited output capability could clip to reach that same 75dB. Not that my Denon has or will, but another, lower rated amp might...

I will try what turning the channel level down and upping the gain will get me then as I've already run all the risk there is to run as long as I keep it to 75dB whitenoise at the listening position.


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## DisTreSs (Sep 27, 2008)

thxgoon said:


> I moved the thread to Home Theater Components.
> 
> Thanks for the first impressions! I'd follow Steve's advice and set the gains on the amp such that your level settings in the receiver are at 0. This will rule out any difference in sound as a consequence of pre amp gain. Also, try some measurements and see if 'louder' is actually louder or if it is perceived. Do you have REW installed? It would be neat to see some sweeps on one amp vs the other. Come to think of it... maybe I'll try that :bigsmile:


thx for moving 

Well, the channel level actually goes from -12 to +12 dB.
If I remember correctly, I had them at about -11 before and now have them at about -5.
I'll set them to -12 and turn the gain up on the amps when I get home 
Overall reciever volume is always set to 0 for my tests.

I did d/l REW some time ago but did not really make use of it since it didn't calibrate properly. I set the whitenoise of my receiver to 0, SPL showed 75dB and entered this als calibration value in REW. The problem was that when I played a sweep, it was nowhere near what it should be.
When I noticed that even when the room was silent, it still read 65dB, I knew there was something wrong. After reading recently that I should not have plugged my spl-meter into the mic-in but rather should have used the line-in, maybe this is what I did wrong?


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## thxgoon (Feb 23, 2007)

DisTreSs said:


> Oh , so the gain control is actually not regulating voltage supply to the amp and therefore not telling the amps how many watts to deliver...??


The gain controls the level of the input signal. In pro audio there is a wide range of signal levels and it's useful to match the input of the amp with the output of a source.

You could try setting the channel levels to -12 but this basically raises your noise floor by that much and reduces dynamic range. Set the levels all to 0 if you can and adjust the knobs on the amp to get 75db.


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## DisTreSs (Sep 27, 2008)

thxgoon said:


> The gain controls the level of the input signal. In pro audio there is a wide range of signal levels and it's useful to match the input of the amp with the output of a source.
> 
> You could try setting the channel levels to -12 but this basically raises your noise floor by that much and reduces dynamic range. Set the levels all to 0 if you can and adjust the knobs on the amp to get 75db.


Did what you said but there wasn't really any difference between this and setting the channel level on the receiver lower and gain on the amp higher.

I also tried switching back to the amps of the receiver and wasn't too disappointed , but unfortunately I don't have any spades so switching back quickly to the EP2500 wasn't possible.
I'm gonna go out tomorrow and get some connectors to allow me to do better A/B-ing.

I also wanted to be able to quantify results with REW but keep getting the message that the signal level is too low even though I do get a FR-curve.
Since I didn't have too much time left, I just watched the SPL-meter as I played the frist track of a CD that is relatively constant in output. Both with the amp and the receiver, the signal never went above 95dB at the listening position and hovered between 90 and 95dB...
Not really scientific, I know, but hopefully that will change soon and at least now I know I'm not killing my speakers this way.


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