# Adding sub to "full range"...



## glaufman (Nov 25, 2007)

Hi there... I've been running a pair of Klipsch RF-3 Towers for afew years as my mains, recently added a used RC-3II as center (used) and a pair of tin cans for rears... (not that bad really, just not worth the details)... 

the RF-3's are spec'd to roll off at 37Hz, which is supported by my scans in REW... I'm now thinking of adding a sub to extend down for movies, and perhaps add backup even in music... music is and has always been the primary goal of my setup, but movies are gaining traction...

I'm aware of the "normal" 80 Hz crossover between mains and sub, but I would rather use my RF-3's to their fullest extent, and only use the sub to fill in where necessary...especially important in music, in my opinion, not to mention I spend the money on the towers, why use them as monitors? at any rate...

The issue becomes, my AVR, once the setting of the fronts is moved from large to small, only allows a cutoff as low as 60 Hz, more than half an octave above where my fronts are usable down to... so I'm looking for ideas...

One I've come across is leaving the sub set to off in the AVR and the fronts set to Large, and pulling the preamp out from the AVR as my sub signal, and using the crossover in the sub to limit it to lower than 37Hz... this sounds like a good idea, except I'm afaid that certain scenes could overdrive the fronts, as I already hear what I think is them flapping (yes, I turned it down right away...)...

So then I thought I could turn down the LFE mix on the receiver to a point where the fronts are safe, and turn up the gain on the sub... what does everyone think of this?

Obviously another option is to connect the sub to the sub output, and leave the fronts as large, but as I understand it, then the whole LFE could be pumped into the fronts, which doesn't do me much good...

Help?


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## superchad (Mar 7, 2008)

Can you hook up main speakers in sub and use it a s a high pass filter? I think there are ways you will be able to get what you want but I have always had full range speakers and my Rotel pre can set each speaker from 40HZ up 150Hz so I never had to think that hard, I run full range fronts, 40Hz for center, and 80Hz for surrounds. Also I couldnt agree more about driving your speaker lower if it can handle it, there is alot of debate about the strict 80Hz rule (which I feel was mostly established with smaller speakers in mind, not the best ones) but I think that only applies if you can safely do it any better, after trying it both ways 80HZ across the board doesnt cut it.


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## atledreier (Mar 2, 2007)

I have very capable fronts. They can easily handle 40Hz at reference, and lower down if I don't go mental. Still, they sound so much sweeter when I cross them over at 80Hz. A properly set up subwoofer will "always" outperform a fullrange speaker down low. You are not using your system to it's full potential if you DON'T cross them over at 80Hz.


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## jakewash (Nov 29, 2007)

If you have a very capable sub that will blend well with the mains having the crossover at 60 isn't that bad of a deal. I am able to set my crossover to 40 or 60 and I really can't hear much difference if any with that setting for music or movies and like you my mains are good to below 40hz. Before trying all the other ways, try the 60 hz setting and see what it is like, you may find you like it.


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## WmAx (Jan 26, 2008)

The only way to get ideal integration and sufficient main protection as you seem to desire, it seems, is with an external active crossover with a great deal of flexibility/adjustment that your internal AVR crossover lacks(_nearly all receivers have limited crossover adjustments_). You could use, or example, a Behringer DCX2496, which would allow perfect integration, as this is a very powerful DSP outboard crossover/filter processor. But unless your receiver has a way to feed out the pre-amp signal AND feed the now processed signal back into the amplifier section of the AVR - you will not be able to use this method.  The only way to get this method to work would be to use an outboard amplifier for the mains, thus using the AVR only as a pre-amp for the mains. The total cost, best case scenario, to add both the procesor and the amplifier, is probably in the $500 USD range.

-Chris


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## hddummy (Mar 9, 2007)

what is the model number of your AVR?


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## Mike Cason (Mar 17, 2007)

I too, have a Rotel receiver/amp with the ability to crossover the subs. Xover points are off, 40,60,80, 100, and 120 hz.

I built some really large custom mains and the dual sub tower in my avatar. I've played with the speaker setups in all configurations many, many times. My final optimal quality listening results for both music and movies to get the full benefit of the mains and the subs, is to set my mains to small, even though my mains are monsters, and have set my xover to 60 hz cutoff to the subs through the LFE sub outs. 

This does two things that help me get the most out of my speakers. It doesn't "muddy" up my subs with anything higher than 60 hz because that's not what I built them for. Any higher freqs really have an impact on the quality of the bass my subs produce because they are also carring those extra higher frequencies that the mains are intended to produce, not the subs. 

At 60 hz with all the speakers set to small, all 60 hz signals and below are sent to the sub through LFE and the rest of the signals are sent to my mains and surrounds. I get the cleanest and highest quality music and movie reproduction in this mode. Most mains and satellites should be able to reproduce 60 hz and up very clean in this mode. I used to have the mains set to large, but I have since changed them back to small with much improved results. You'll just have to keep working with your testing.

Different AV receivers have different features, settings, and outputs, so it would do you well to spend a bit of extra time with demos of different types of music and movies until you are tweaked in to your best.

I would definately use your LFE output to your sub(s), and set the mains to small and give it a try. That's what those LFE outputs are for. I think you will be very happy with that setup. I've seen the daisy chain of the main speaker wires from the receiver wired to the sub, then out of the sub to the mains. I've never liked that and have always had less than desirable performance this configuration. I've tried it on a couple of systems.

You mentioned you're desire was intended for music so I've included a chart showing the range of most musical instruments. By looking at this chart, you can see how much more musical reproduction has to be carried by the sub between 60 and 80 hz. 

I hope this helps and have fun.....

Mike


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## glaufman (Nov 25, 2007)

Glad to hear I'm not the only one on that...I've always felt the 80Hz number was more to get the speakers off the floor to allow ideal placement for imaging that it was abuot being the actual point hearing becomes non-directional... In my case I don't have any problem getting the driviers into the place I want for imaging, so no need for small speakers, so I can afford the lower crossover if I can figure out how to do it...
a friend suggested connection using the sub to cross the fronts, just as you say... I don't have any reason not to, other than making sure that whatever sub I get doesn't color the audio it then sends to the fronts... suggestions? 
Other than that requirement, I would have said I was counting on getting a Klipsch sub, but seeing their offerings, I don't think any help with this kind of connection, so I'm open to suggestions...


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## glaufman (Nov 25, 2007)

atledreier said:


> I have very capable fronts. They can easily handle 40Hz at reference, and lower down if I don't go mental. Still, they sound so much sweeter when I cross them over at 80Hz. A properly set up subwoofer will "always" outperform a fullrange speaker down low. You are not using your system to it's full potential if you DON'T cross them over at 80Hz.


Are you suggesting this for music as well as movie mode?


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## glaufman (Nov 25, 2007)

jakewash said:


> If you have a very capable sub that will blend well with the mains having the crossover at 60 isn't that bad of a deal. I am able to set my crossover to 40 or 60 and I really can't hear much difference if any with that setting for music or movies and like you my mains are good to below 40hz. Before trying all the other ways, try the 60 hz setting and see what it is like, you may find you like it.


Fair enough... only 1 thing: since I don't yet own a sub, and have no friends who's subs are "portable," I have to make a purchase before I can run the taste test, therefore I want to make sure before I purchase that the sub is capable of a backup plan just in case...

Also, knowing myself, I'll always feel bad that I'm not using the lower range of the towers... especially for music...


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## glaufman (Nov 25, 2007)

WmAx said:


> The only way to get ideal integration and sufficient main protection as you seem to desire, it seems, is with an external active crossover with a great deal of flexibility/adjustment that your internal AVR crossover lacks(_nearly all receivers have limited crossover adjustments_). You could use, or example, a Behringer DCX2496, which would allow perfect integration, as this is a very powerful DSP outboard crossover/filter processor. But unless your receiver has a way to feed out the pre-amp signal AND feed the now processed signal back into the amplifier section of the AVR - you will not be able to use this method.  The only way to get this method to work would be to use an outboard amplifier for the mains, thus using the AVR only as a pre-amp for the mains. The total cost, best case scenario, to add both the procesor and the amplifier, is probably in the $500 USD range.
> 
> -Chris


I was thinking about an outboard crossover, sounds like fun, but I'm jhoping for a more elegant solution... I'm not familiar with teh 2496, but I'll look it up...


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## glaufman (Nov 25, 2007)

hddummy said:


> what is the model number of your AVR?


Sony, DTB940... I think...


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## glaufman (Nov 25, 2007)

Mike Cason said:


> I've played with the speaker setups in all configurations many, many times. My final optimal quality listening results for both music and movies to get the full benefit of the mains and the subs, is to set my mains to small, even though my mains are monsters, and have set my xover to 60 hz cutoff to the subs through the LFE sub outs.


One question I have is: when you had the cross set lower than 60, did you play a bit with altering the positions of the mains to avoid interference? different listening positions?



> I would definately use your LFE output to your sub(s), and set the mains to small and give it a try. That's what those LFE outputs are for. I think you will be very happy with that setup. I've seen the daisy chain of the main speaker wires from the receiver wired to the sub, then out of the sub to the mains. I've never liked that and have always had less than desirable performance this configuration. I've tried it on a couple of systems.


Sorry to get semantic, but strictly speaking, the LFE is a channel on the program media, not an output from the decoder or preamp... the decoder/preamp processes this channel (in conjunction with the other channels and the settings its given) to create a sub output... strictly speaking, the LFE is not intended to necessarily be the sub output... see this article from Dolby... http://www.dolby.com/assets/pdf/tech_library/38_LFE.pdf



> You mentioned you're desire was intended for music so I've included a chart showing the range of most musical instruments. By looking at this chart, you can see how much more musical reproduction has to be carried by the sub between 60 and 80 hz.


Yes, indeed... I've seen the chart before... I'm in agreement about preferring 60Hz to 80Hz crossover... another question... how does say a bass drum fit into this chart? How about a bass guitar?



> I hope this helps and have fun.....


It certainly does start to help... and if this isn't fun, why are we doing it?

Thanks everyone for all the info and help... I hiope this continues a while until I figure out what I want to do...


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## WmAx (Jan 26, 2008)

glaufman said:


> I was thinking about an outboard crossover, sounds like fun, but I'm jhoping for a more elegant solution... I'm not familiar with teh 2496, but I'll look it up...


Elegant - certainly not. But it is the best solution from a functional standpoint. The unit allows for precise variable control and virtually any type/slope of crossover that you could practically want to use. It also has dynamic protection systems that you can set to limit output at specific frequencies at specific output levels. You will not be limited as to your options to find the best crossover point/type/rate. You can also use the DCX to apply room correction filters for bass in order to compensate for some room acoustic issues. You can also use the DCX to customize the roll off characteristics of your sub-woofer: this is a huge bonus because many subjective sound quality preferences_(subjective bass 'tightness' is one very largely effected factor, for example_) are directly related to the bass cut off point and slope of the LF system. It offers transparent operation and is very easy to use, especially if you use a laptop PC to hook up to it using the Behringer GUI software. You can do all settings from the front control panel of the DCX as well, but it takes more time to do so for many parameters. Main problem with this approach as I stated before: having to use an outboard amplifier for the main speakers due to lack of method to re-feed the processed pre-amp signal back to the internal AVR speaker amplifiers.

-Chris


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## hddummy (Mar 9, 2007)

I think I would use the 60Hz crossover point from mains to the sub and connect the sub to the sub-out on the AVR. If you crossover too close to the lower range of a speaker then the natural roll-off of the speaker combines with the crossover roll-off to make a total roll-off slope steeper than expected by AVRs. You could potentially have a dip in the systems response in the crossover region.

However, if you really want to take mains to their full range, I would set them to large and set the AVR to send the LFE to the mains. Run pre-amp mains to the sub and use the sub's built in Low pass crossover to limit it's upper extension. I've never seen a powered sub that didn't have one. You can then use a passive crossover before the mains to limit their low end to whatever frequency you want. A first order high pass filter should do it. This is basically a capacitor (or group of capacitors) in line between the receiver and the speaker and should cost about 15$ per side. I believe speaker makers already build this into their crossovers to keep you from over-driving the speaker with material that is too low. Granted that the built in ones are probably better tuned and a little more sophisticated, but the concept is the same. Regardless, it isn't as flexible as the active crossover/external amp solution, but it is a very inexpensive thing to try.


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## glaufman (Nov 25, 2007)

hddummy said:


> I think I would use the 60Hz crossover point from mains to the sub and connect the sub to the sub-out on the AVR. If you crossover too close to the lower range of a speaker then the natural roll-off of the speaker combines with the crossover roll-off to make a total roll-off slope steeper than expected by AVRs. You could potentially have a dip in the systems response in the crossover region.


Never thought of that... on first inspection at least...I wonder what other people have to say about that... 

Don't the "guidelines" usually state to set the crossover at the rolloff point of the mains (and of course to set the crossover control on the sub to maximum)? Woudn't this then cause an issue more often than not?


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## hddummy (Mar 9, 2007)

I've just always followed that rule and I don't think any guidelines would convince me otherwise. If recommendations don't agree then I'll bite my lip about it. I'm sure the crossover slopes built into the AVR also have an influence on how close to the speaker roll-off you can crossover. That is one of the nice things about external active crossovers...you have complete control over these sort of things.


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## conchyjoe7 (Aug 28, 2007)

Why not set up your system for no sub at all during music playback? If your mains as you say can go below 40hz, it's unlikely a sub will help much *depending* on how loud you listen, the type of music you listen to (hip hop/rap will require a sub) and the power of your AVR. I listen to music in stereo (most of the time) with my mains set to large and my subs off. When viewing movies, I go ahead and cut in the subs (I have 2) which are crossed over at 80hz (I use the recommended THX crossover point despite the fact that my mains are easily usable to ~24hz). In most cases, IMHO your speakers will handle 90% of all music no problem, but as others have said; you should try it both ways as simply by crossing over at 60hz or 80hz will take a huge drain off of your AVRs output as well as the bass drivers of your speakers and in all likelihood make your system sound a lot more "open", "detailed" and "smoother".
Just my 2 cents worth...hope it helps!
Cheers,
Konky.


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## atledreier (Mar 2, 2007)

The thing is, and like I said before, a *properly set up* sub will outperform your mains. A properly set up sub will have EQ and freedom of location that you don't have with your mains. The response from a properly EQ'ed and placed sub will be smoother and have more headroom than your mains. Music or movies, there is no fundamental difference. It's all sound. Movies often put more of an emphasis on extension, where music demand more agility and precision. This is a broad generalization though. 50% of a movie soundtrack is music.*

*Non-scientific guesstimate


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## Mike Cason (Mar 17, 2007)

glaufman said:


> One question I have is: when you had the cross set lower than 60, did you play a bit with altering the positions of the mains to avoid interference? different listening positions?
> 
> 
> 
> ...


Well, I don't have an arguement with the Dolby link because I'm certainly not a pro. I'm just a novice builder but have built a system that everyone who has listened to it says it's the finest sounding they have ever heard, bar none. I'm just providing you with the settings that I've found to give me the most, and best, sound I can get with my system. I usually listen to music and some concerts in two channel only because the mains are so good.

My Rotel has the sub output and that's the one I use. I am to assume that is the LFE rca jack as well. The Rotel was their top of the line unit so that may explain why my subs get the freqs I set the crossover to.

As far as bass guitar reproduction, I hear everything, even the real low bass that leaves your shirt sleevs wobbling in the air due to the long sound waves. Joe Satraini and the Blue Man Group is literally chest pounding at high levels. Kick and kettle drums are clean. I've ordered the Reckhorn B-1 to fine tune it even better and am expecting a real treat.

As far as placement, my system is so large I can't move it around so I've stacked my subs as shown in the Avatar. I did try having them in two different places, but the co-locating works fantastic. I've even broken the seal in my 5' x 6' plate glass window in the living room. I'm attaching a photo to show why I can't move it around and still maintain decent seating.

Good Luck....:jump:


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## tonyvdb (Sep 5, 2007)

The 80Hz crossover setting is the standard set by THX. Although this may seem high it is the best compromise as a good sub will easily handle the rest. I understand your concern for letting the mains do what they can do but this puts more strain on the receivers amp/power supply section and this in turn limits the maximum output the receiver can do for the surrounds.
The mains I have play down to 32Hz and in pure two channel mode they sound great but for movies I dont want that. Remember that even with a crossover setting of 80Hz this does not mean the frequencies below that dont get through it just means that at 80hz the curve will then fall off so blow 50hz there is no output. Does your receiver not have an independent eq for the mains? You could then just roll off the frequencies below 30hz.


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## salvasol (Oct 31, 2006)

Do you have the option on your receiver to send the sub output to main speakers and sub at the same time???? ... my Yamaha RXV 2700 has that option, I'm using JBL Stadiums for the main front, they go down to 35Hz; so what I did is to set them to small (according to manual, it doesn't matter if they're set to small or large when using for sub output), crossover to 80HZ and sub output send to Both (front speakers and Sub) :yes: :yes:


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## glaufman (Nov 25, 2007)

hddummy said:


> I've just always followed that rule and I don't think any guidelines would convince me otherwise. If recommendations don't agree then I'll bite my lip about it. I'm sure the crossover slopes built into the AVR also have an influence on how close to the speaker roll-off you can crossover. That is one of the nice things about external active crossovers...you have complete control over these sort of things.


That of course raises a few questions as well...
How much margin is "adequate" to ensure the AVR doesn't hit the slope on the speakers... ?
I can verify by scans, but do speakers (not talking about low end stuff here) typically roll off where the mfrs specify it, or do they give a little "extra"?


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## glaufman (Nov 25, 2007)

conchyjoe7 said:


> Why not set up your system for no sub at all during music playback? If your mains as you say can go below 40hz, it's unlikely a sub will help much *depending* on how loud you listen, the type of music you listen to (hip hop/rap will require a sub) and the power of your AVR. I listen to music in stereo (most of the time) with my mains set to large and my subs off. When viewing movies, I go ahead and cut in the subs (I have 2) which are crossed over at 80hz (I use the recommended THX crossover point despite the fact that my mains are easily usable to ~24hz). In most cases, IMHO your speakers will handle 90% of all music no problem, but as others have said; you should try it both ways as simply by crossing over at 60hz or 80hz will take a huge drain off of your AVRs output as well as the bass drivers of your speakers and in all likelihood make your system sound a lot more "open", "detailed" and "smoother".
> Just my 2 cents worth...hope it helps!
> Cheers,
> Konky.


Only real reason here is it's not as convenient to change in the AVR as perhaps some, so I'd rather to pick one setup to use for both modes, especially for the WAF... also, even thought I don't normally listen to the hip hop and rap, I want to be able to perform there when necessary...


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## glaufman (Nov 25, 2007)

atledreier said:


> The thing is, and like I said before, a *properly set up* sub will outperform your mains. A properly set up sub will have EQ and freedom of location that you don't have with your mains. The response from a properly EQ'ed and placed sub will be smoother and have more headroom than your mains. Music or movies, there is no fundamental difference. It's all sound. Movies often put more of an emphasis on extension, where music demand more agility and precision. This is a broad generalization though. 50% of a movie soundtrack is music.*
> 
> *Non-scientific guesstimate


THX generally quotes that 70% of a movie soundtrack is dialog... 
I'm of the opinion that there IS a difference between movie and music, the sound is different... yes, a perfect system in a perfect room will sound superb for both, but since that isn't an option, there are tradeoffs... in music, I much prefer the sound of 2 good full range speakers to 2 monitors backed by a sub with an 80Hz crossover... in movies, as long as it's not above 80Hz, I believe the exact crossover point to be less of an issue... in music, the more extension you can get out of the stereo pair the better, assuming of course, you don't sacrifice flatness, and have the ability to properly place and aim them...
Lastly, in some regards the full range allows more placement options than the single sub, to the extent that they're two separate sources, although there can be phase issues, and they have to be placed somewhere that provides adequate imaging, careful placement of 2 sources can help combat modes better than 1 source.
Of course, if you sacrifice response, all bets are off...


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## glaufman (Nov 25, 2007)

Mike Cason said:


> Well, I don't have an arguement with the Dolby link because I'm certainly not a pro. I'm just a novice builder but have built a system that everyone who has listened to it says it's the finest sounding they have ever heard, bar none. I'm just providing you with the settings that I've found to give me the most, and best, sound I can get with my system. I usually listen to music and some concerts in two channel only because the mains are so good.
> 
> My Rotel has the sub output and that's the one I use. I am to assume that is the LFE rca jack as well.


Like I said, I was getting semantic, and I don't know the Rotel, but most amps will have a sub output, but not an LFE output... they're different. 



> As far as bass guitar reproduction,


good luck with the Reckhorn... as for bass guitar, and the other instruments, the question was really what frequencies the lowest fundamentals run down to...


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## Mike Cason (Mar 17, 2007)

tonyvdb said:


> The 80Hz crossover setting is the standard set by THX. Although this may seem high it is the best compromise as a good sub will easily handle the rest. I understand your concern for letting the mains do what they can do but this puts more strain on the receivers amp/power supply section and this in turn limits the maximum output the receiver can do for the surrounds.
> The mains I have play down to 32Hz and in pure two channel mode they sound great but for movies I dont want that. Remember that even with a crossover setting of 80Hz this does not mean the frequencies below that dont get through it just means that at 80hz the curve will then fall off so blow 50hz there is no output. Does your receiver not have an independent eq for the mains? You could then just roll off the frequencies below 30hz.


I've played with the 80hz setting and it affects the sound quality of my mains. I've paralleled two Lambda TD12s drivers in each main, as well as the Scan Speaks I have for my mids. The mains aren't as detailed with the higher setting, so I'm very happy with the 60hz. The two Lambdas in parallel can reproduce the 60 to 80hz much better than the sub. As far as what THX recommends, it is just that, a recommendation. The end user tweaks their system for their optimal performance and pleasure.

I don't have a crossover adjustment for the mains.

My Rotel processor/amp is a very high current amplifier and can easily power my mains, center, and two surrounds. I have a separate amplifier for my two center backs.

This is not to be taken as an arguement, but rather a discussion. That's why we have our forums to share information with each other.

Mike


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## tonyvdb (Sep 5, 2007)

Mike Cason said:


> This is not to be taken as an arguement, but rather a discussion. That's why we have our forums to share information with each other.
> 
> Mike


Sorry Mike, no argument was intended here I was just stating what I know and what usually works.
At this moment I have my mains set for Full with no crossover as my sub is a little week and I have a separate amp driving them but this will change once I get my SVS PB13 Ultra.


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## superchad (Mar 7, 2008)

atledreier said:


> I have very capable fronts. They can easily handle 40Hz at reference, and lower down if I don't go mental. Still, they sound so much sweeter when I cross them over at 80Hz. A properly set up subwoofer will "always" outperform a fullrange speaker down low. You are not using your system to it's full potential if you DON'T cross them over at 80Hz.


You are wrong plain and simple, if your system sounds better crossed over at 80HZ maybe that works for you but in my system it isnt the case, with my power reserves, speakers that go down to 16Hz.... bi-amps with outboard active crossover, 80Hz isnt the way to go. What works in your system does not become an absolute rule.


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## Mike Cason (Mar 17, 2007)

tonyvdb said:


> Sorry Mike, no argument was intended here I was just stating what I know and what usually works.
> At this moment I have my mains set for Full with no crossover as my sub is a little week and I have a separate amp driving them but this will change once I get my SVS PB13 Ultra.


I understand your point and is well taken. 

You will love your SVS subs. I've heard a lot of good things about them..

I broke all the rules by putting two RLP 15s in a 5 cu ft box with 4 passive radiators each, but the results are fantastic. I have a lot of rebuilds, (total of 5 for the sub alone) starting 3 or 4 years ago to achieve the sound I am most happy with.....we call this stuff DIY and we are supposed to enjoy our projects.

BTW....The Lambda line of woofers and subwoofers were custom designed, machined, and built in Florida and as far as I could tell, was one of the highest sought after driver in the world. Nick didn't charge enough for them and eventually sold out. I was negotiating purchasing the business and inventory from him but am lacking in the audio technical department to make a success with their continued production.


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## atledreier (Mar 2, 2007)

superchad said:


> You are wrong plain and simple, if your system sounds better crossed over at 80HZ maybe that works for you but in my system it isnt the case, with my power reserves, speakers that go down to 16Hz.... bi-amps with outboard active crossover, 80Hz isnt the way to go. What works in your system does not become an absolute rule.


This is exactly why I put the 'always' in quotes. Not many have mains that will play comfortably in the lower ranges. I have no signs of strain when playing low stuff on them, they have no problem handling music on their own, but even so they are sweeter and cleaner up high with the lower end crossed off. I would think that about most systems really, regardless of quality. I have good headroom, a bi-amped setup and not a very big room to fill.


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## superchad (Mar 7, 2008)

sorry I didnt see quotes but all the same I think in general you are correct but for those of us with true full range and various other equipment that is not really the norm the 80hz rule doesnt apply. I didnt want to start a debate just adding that there are almost always exceptions to even the most universally believed rules of thumb, if my goal wasnt a music first system I believe I would probably be firmly in the 80hz camp with most others......cheers


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## jakewash (Nov 29, 2007)

Wasn't that 80hz cross over thing brought out/setup by THX anyway?

IMO, it really has no basis when it comes to music systems unless your system can not handle frequencies below that with authority. Speakers should be set up as dictated by the capabilities of each speaker or system and the way each individual likes, as that is all that really matters.


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## hddummy (Mar 9, 2007)

This one has taken on a mind of it's own. Let's summarize. 80Hz crossover is a good rule of thumb for "movie centric" systems but is still largely determined by personal taste and system capability. If you don't have the time or necessary resources to test your system out, set it and forget it. If you want to play around with different frequencies...by all means. For "music centric systems", many prefer to leave full range speakers handle the bulk of the low end material but will probably need to crossover to a sub and some level. Again...do some testing.

Now...as for glaufman's original question... Have we sufficiently turned you around enough so that you have no idea where the donkey's tail needs to go?


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## glaufman (Nov 25, 2007)

tonyvdb said:


> The 80Hz crossover setting is the standard set by THX. Although this may seem high it is the best compromise as a good sub will easily handle the rest.


Although I believe in THX, this is one area where I differ from their opinion... I prefer a lower crossover...



> I understand your concern for letting the mains do what they can do but this puts more strain on the receivers amp/power supply section and this in turn limits the maximum output the receiver can do for the surrounds.


I don't believe my receiver is being strained, and I certainly have plenty of output room for the surrounds...



> Does your receiver not have an independent eq for the mains? You could then just roll off the frequencies below 30hz.


It does, but the characteristic is limited to the point where I don't think this is practical... it's only 3 band, the bass and treble can only adjust levels and cutoffs, (high for the bass, low for the treble) and level and center for the mid, without an adjustment for Q or BW...


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## glaufman (Nov 25, 2007)

salvasol said:


> Do you have the option on your receiver to send the sub output to main speakers and sub at the same time???? ... my Yamaha RXV 2700 has that option, I'm using JBL Stadiums for the main front, they go down to 35Hz; so what I did is to set them to small (according to manual, it doesn't matter if they're set to small or large when using for sub output), crossover to 80HZ and sub output send to Both (front speakers and Sub) :yes: :yes:


I don't think I understand... if the mains are set to 80Hz, shouldn't anything below that be sent only to the sub? You can set the mains to 80 and still get the sub output sent to the mains? that doesn't seem to make sense...


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## hddummy (Mar 9, 2007)

glaufman said:


> I don't think I understand... if the mains are set to 80Hz, shouldn't anything below that be sent only to the sub? You can set the mains to 80 and still get the sub output sent to the mains? that doesn't seem to make sense...


That does seem somewhat counter intuitive, but I think what happens is that both the sub and mains get material below the crossover and LFE. In other words, the mains get full spectrum and LFE. The sub gets low frequency material from the mains and LFE. You'd better have some serious capability on the mains to handle that.


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## superchad (Mar 7, 2008)

I run full plus sub in my Rotel, it is useful when you have full range fronts for extra depth in the presentaion but center and all surrounds follow what ever cross over you set. If my speakers couldnt handle bas as low as they do (Iam down -10db at 16Hz) I wouldnt use this feature as it could be a woofer killer.


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## glaufman (Nov 25, 2007)

hddummy said:


> Now...as for glaufman's original question... Have we sufficiently turned you around enough so that you have no idea where the donkey's tail needs to go?


Actually, I think I have a direection as to how I'll probably go, at least to start, which'll be to use the 60Hz crossover the rcvr allows, and see how it sounds, since noone argued (at least not that I've read yet) with the assertion of staying away from the speaker's cutoff in any case... I'd still like to hear opinions on that, and answers to some of the questions that raised in my mind, basically...
How much room is adequate to keep the crossover above the mains' cutoff?
The other questions it raised, such as is the receiver supposed to do this itself, I can answer empirically, once the wife goes away for a few days...

The only question left really will be whether I make sure to get a sub with high level in/outs, so I can eventually use its crossover to power the mains in case I decide I need ot listen to that to see if it's better, and what people think, if the crossover in these subs has characteristics sufficiently flat etc to do this effectively, or if it's a gimmick to stay away from...


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## glaufman (Nov 25, 2007)

hddummy said:


> That does seem somewhat counter intuitive, but I think what happens is that both the sub and mains get material below the crossover and LFE. In other words, the mains get full spectrum and LFE. The sub gets low frequency material from the mains and LFE. You'd better have some serious capability on the mains to handle that.


I think that depends on how the receiver is designed, and how you've set it up... 
Theoretically, the receiver is under no obligation to send LFE to the sub... if you tell the receiver your mains are "large," that implies full range, in which case it can very well send the entire LFE to the mains and nothing to the sub... (according to Dolby) ... if all the sats are set to small with a crossover, then the rcvr should transistion via opposing rolloffs from sats to sub at that rolloff... not that the mains shouldn't get anything below that freq, they have to in order to make the transition smooth, but the signal they're given should rolloff... another question becomes at what slop do they rolloff? 1st order, 2nd order, etc... (6 db, 12 db per octave, 20, 40 db per decade?) I plan to run some tests on my AVR to see what it actually does... I'll post the results if anyone's interested, but due to other projects it may be a while before I get around to it...


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## glaufman (Nov 25, 2007)

superchad said:


> I run full plus sub in my Rotel, it is useful when you have full range fronts for extra depth in the presentaion but center and all surrounds follow what ever cross over you set. If my speakers couldnt handle bas as low as they do (Iam down -10db at 16Hz) I wouldnt use this feature as it could be a woofer killer.


that's one thing I'm afraid I'm doing now, which is one reason I want to add the sub, is certain scenes seem to be doing things to my fronts, that I don't pick up when I run a scan, so I don't think it's room acoustics, but rather trying to play freqs that are too far down their slope to hear effectively, so my LFE mix is turned way up... of course, it could simply be listening to the harmonics with a severely reduced fundamental, since it's so far down their slope... I really have to turn that LFE down and see what happens...

not enough hours in the day...


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## BrianAbington (Mar 19, 2008)

From the research I have done when 5.1 surrround was originaly demoed they had a subwoofer associated with each channel then something bigger for the .1...so I would find a way to add a sub to all of the channels...then happyness will ensue.:yay:


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## glaufman (Nov 25, 2007)

SQCherokee said:


> From the research I have done when 5.1 surrround was originaly demoed they had a subwoofer associated with each channel then something bigger for the .1...so I would find a way to add a sub to all of the channels...then happyness will ensue.:yay:


Well, I'm a full believer in themore subs the better... (pay no attention to the fact that I have yet to own one)...

My ultimate goal is a sub underneath each and every seating position...

Anyone who want ot give me a job that'll let me afford that I'm soliciting offers...


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## tonyvdb (Sep 5, 2007)

glaufman said:


> My ultimate goal is a sub underneath each and every seating position...


Your looking at lots of issues with that idea. Phase cancellation being one of the biggest. Your far better off adding one Butt kicker to each chair/sofa.

Multiple subs installed improperly and set up wrong will not improve bass response and will most likely cause huge dips and peaks in the room of the frequency response. Room treatment, placement and base trapping becomes crucial.


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## superchad (Mar 7, 2008)

tonyvdb said:


> Your looking at lots of issues with that idea. Phase cancellation being one of the biggest. Your far better off adding one Butt kicker to each chair/sofa.
> 
> Multiple subs installed improperly and set up wrong will not improve bass response and will most likely cause huge dips and peaks in the room of the frequency response. Room treatment, placement and base trapping becomes crucial.


I couldnt agree more, more subs can just add more problems if not done right.... not only is a Butt-Kicker going to give you the same percieved result it is going to be alot cheaper, I have Aura Bass Shakers in all my chairs and they work great....they only cost me $10 for each unit. I have heard (felt) the Butt Kicker units and they perform no better than the Bass Shaker but the cost 20x as much, they are both bass resonator units but also the Bass Shakers are much smaller and easier to integrate IMO.
Dont let the Bass Shakers price fool you, I want the best performance possible for the money and have a system with over $20,000 in equipment, I refrence this to assure you I would pay for the Butt Kicker units if I thought they were better or worth it. I am not sure if Bass Shakers are available anymore as I seem to remember I got them cheap on closeout special. They sat in their boxes for over 2 years before I installed, my friend turned me onto them and has them installed in his seats. No matter which unit these are going to be a better and easier to work with....and cheaper solution you need to explore. Cheers


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## bone215 (Dec 15, 2006)

Seems like alot of different experiences. My experience using two stereo subs up front underneath my main L and R speakers differs. I used four different types of speakers and in each case I found that running into the sub first, and then from sub up to speaker using hi level line out was best. The subs default was to send everything above 150Hz to the speakers so in this case the subs were handling alot. There was no localization issues since the subs were directly below the speakers. The set up, in essence, made a full range speaker system good down to 22Hz. Once I got past the thought of how high I thought 150Hz was, I never looked back.
I tried various other hook ups and different crossover settings, but overall, running the subs the way I did sounded best=for me in my room.

Many speakers use a large woofer and they play pretty high up into the frequency ranges. Its not like a 12 or 15 can't play that high.

The room and placement plays a large role.


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## mayhem13 (Feb 2, 2008)

bone215 said:


> Seems like alot of different experiences. My experience using two stereo subs up front underneath my main L and R speakers differs. I used four different types of speakers and in each case I found that running into the sub first, and then from sub up to speaker using hi level line out was best. .


I agree with the first part of the response. I use dual Dayton RS series 10" subs in 1.5 cuft sealed enclosures next to my mains crossed over at 80hz using the high level in/outs. This allows my mains to handle a bit more power and they sound a little more airy in the midrange. The subs handle the left and right lows and i use the LFE output strictly for HT use down to sub 20hz. I was able to build the two subs for under $500 for the pair and for Music, i am never wanting. I don't have any phase issues that i can't control with the plate amps controls and they integrate perfectly with the mains so that i can't even tell that they're there ! As for wanting to use your mains to their full potential that's your call but i feel speaker manufacturers are always trying to extend low frequency response as far as possible in large boxes. You would probobly find that the free air frequency of your woofers in your mains is probobly in the 50-60hz range and asking them to play lower than that is stretching their capability to the end of their usefull range and beyond creating a power soak on your AVR as mentioned above resulting in distortion from both the AVR and the non linear response of the woofer excursion. Removing frequencies from 80hz and below will DEFINATELY improve the sound of your front soundstage.


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## DougMac (Jan 24, 2008)

jakewash said:


> Wasn't that 80hz cross over thing brought out/setup by THX anyway?
> 
> IMO, it really has no basis when it comes to music systems unless your system can not handle frequencies below that with authority. Speakers should be set up as dictated by the capabilities of each speaker or system and the way each individual likes, as that is all that really matters.


My understanding is that they decided based on directionality research. They were working on a .1, not .2 standard. Research showed most folks can't tell direction reliably at less than 100 hz and no one in the test group could under 80 hz, hence the setting of the standard. From what I can tell, little or no consideration was given to equipment.

I couldn't agree more with your last observation.

Doug


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