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Hi.


I read in here, sometime ago, that it's better to redirect bass from

the stereo speakers to the sub, which already produces .1 sound.

My subwoofer is a KEF model 20b, nothing fancy at all. Now, I have

the option of buying some used stands, really good quality, filled with

lead-those-thing-you-shoot-with, for a good price. I have my B&W

602 speakers on them now.


Now I'm wondering if the choice of redistributing the bass from the

mains to the sub is a good idea. I know that you guys are really into

audio, so if you have an opinion about how to use my equipment best,

please chip in. I'm not audio-wise.


Thanks for reading.


Nicholas
 

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Actually, this brings up something I've been wondering.


Sub woofers have the longest throw of any driver due to their size. Because of this, they are the most subject to getting muddy when being forced to quickly react during fast moving passages.


Wouldn't it make sense then to have one sub dedicated to running LFE ... and one used for the low Hz from the rest of your speakers?


Wouldn't this make for tighter bass?



Can this be done by any receivers ... or could it be done by wiring in a certain way?
 

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Quote:
Originally posted by Raistlin_HT
Actually, this brings up something I've been wondering.


Sub woofers have the longest throw of any driver due to their size. Because of this, they are the most subject to getting muddy when being forced to quickly react during fast moving passages.
Hi Raistlin,


While what you intend isn't completely off-base, the confusion about throw and driver size should be clarified. A larger driver *may* be able to move farther than smaller drivers, but in fact output is related to the amount of air moved, or volume displacement. As such, a larger driver in fact moves LESS than a smaller driver to produce the same SPL at the same frequency(in a sealed box or above the resonance of the port).


As for "muddy" bass, this is very much an excursion related matter. For a given driver, the more excursion, the more distortion. Of course not all drivers are created equal, and there are certainly many 12" drivers today which will move more air than many 15" drivers.


While your suggestion to split up the signal would help, you can achieve better results by using both subwoofers for ALL the bass which needs to be reproduced. This way, if the content is heavy on the LFE channel, it still has the headroom of two subwoofers vs. one working hard and the other loafing along.
 

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Mark -



Thank you for the clarification. I am admittedly a relative newbie to HT (I'm sure that is already aparent to you ;)), and welcome all information that can help me become more knowledgable.


Its good to hear that two subs, running all the bass, will work the best! That certainly makes life easier as far as HT setup and design.
 

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Mark,

"While your suggestion to split up the signal would help, you can achieve better results by using both subwoofers for ALL the bass which needs to be reproduced. This way, if the content is heavy on the LFE channel, it still has the headroom of two subwoofers vs. one working hard and the other loafing along."


Is it better for this kind of dual subwoofer setup to have a mono bass signal split between the subwoofers, or could you have stereo subwoofers (for the L/R main output) plus the LFE channel and "small" bass sent to both subs? Would this be a preference issue or is there a benefit to a "mono" dual sub setup vs. a "stereo" sub setup?


Thanks,


Michael
 

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Hi Michael,


An arguement could be made for the setup you propose, and in fact this is one configuration option on the Lexicon MC-12. Is it better? It depends...


The question is if the subs used for stereo operation have decent response at the listening position used singly. In many cases, the optimum placement of two subwoofers will not be in a conventional "stereo" placement, but sometimes that option does work out. Also realize that below 50-100Hz(not sure exactly) there is very little "stereo" information recorded. IE typically L=R, so there would be no difference between the settings.


Do understand such settings, preferences, and bass management techniques are intended to address the most offensive problems first. IF you have a room which is acoustically treated down to the 40Hz realm (Keith Yates designs this way) or your room is so large as to allow good response from multiple locations, certain options open up.


Subwoofer concerns in my mind:


1. relatively smooth response


2. sufficient output/ low distortion *under real situations*


3. true low frequency extension (at real levels)


4. stop the room from rattling


5. achieving >10dB headroom over mains at ~100Hz


6. repeat #4


7. maybe give some thought to directional bass ;)


... Nahh, better to put effort/money into the mains which is where the directional cues are reproduced in the first place.
 

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Mark,


Thanks for the followup information. Since we already own two ACI Titan II LEs, I was considering the stereo subwoofer option (processor is Anthem AVM-20). But our mains (Canton Ergo 92DC) have very good output even down to a 31.5 Hz test tone (nearly flat in-room), so it would seem that we are fine as far as directional bass is concerned.


We have been using one Titan II with the subout connection (LFE plus "small" center bass) and the other Titan II with the main's output to fill in the last octave for the mains. Not exactly the most efficient use of two subwoofers, but it was easy to set up and the wife approved!


Now, I would like to use both subwoofers for the LFE channel, while at the same time fill in the bass for the mains. Given our mains, it seems I might be better off generating a mono bass signal and sending that to both subwoofers instead of trying to produce stereo subs.


Michael
 
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