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Until yesterday, the only way I thought of connecting a subwoofer was to use the pre-pro/AVR's subwoofer/LFE preout, but yesterday I listened to my speakers in a shop with a Servo-15 and that subwoofer was being fed ONLY by the front-left/right preouts (LFE was not being used)! Because the Servo-15 comes with it X-30 crossover box, I suppose that proper filtration was made easy since the original feed to the Servo-15 was a full-range signal.


Unfortunately, I was not prepared in my visit as I did not bring any real bass material to listen to. I suppose my lack of preparation was because I previously swore I would never go back to this shop. But, I did go back and they had Reference Studio 100's, ADP's, 20's (rear), CC and Servo-15 setup in a room.


This setup was being fed by a B&K Ref.50 (I think; and I'm using an Elite 45TX), but the sound coming from those speakers were so full in range I was really enjoying the experience. I have Tuesday off, and as you can imagine I will be going back to that shop with material to really test the low-end portion of their setup.


What I am confused about, though, is that almost everyone I talk to on AVS and HTF seem to only feed their subwoofers via the LFE preout. I would imagine this is because most speakers, including most full-range speakers, are not capable of getting down the subterranean depths of bass. The Servo is capable of 17Hz response according to the Paradigm numbers, and this shop used the included X-30 crossover box and set it to 35Hz.


So, I was wondering what anyone else thought about feeding their subwoofers using the main loudspeaker preouts instead of the LFE? Is anyone doing this?
 

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Originally posted by WanMan
So, I was wondering what anyone else thought about feeding their subwoofers using the main loudspeaker preouts instead of the LFE? Is anyone doing this?
It seems kind of silly to do this for home theater. If not configured to use a subwoofer, most AV Receivers redirect the LFE channel to the main speakers. By using the main left and right pre-outs to feed thge sub, you are getting the same information but you are just using a different route. Additionally, depending on how high you set the low pass filter, you may experience bass nullification at the frequencies where both the main speakers and the subwooder are reproducing. Setting the crossover to 35Hz will minimize this, but those Studio 100s can go pretty low.


Now, if you wanted to blend the subwoofer to the mains in the most seamless way possible, you could connect the main pre-outs to that X-30, use the LPF to send a signal to the subwoofer and the HPF to send the signal to the main inputs of your amp. Like most things in home theater, there is more than one way to do things.
 

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Well, now this brings up an interesting question regarding the integrated receiver or pre-pro processor in question. I would expect that the signal sent out the regular preouts to be full-range, but what about the subwoofer preout? Also, I cannot find for my AVR what frequency range is being sent out the the preouts, or rather what those preouts are capable of sending out.


Naturally, one would not expect a subwoofer preout (LFE) to be over, say, 500 Hz (probably lower), but I would be curious to know what is 'spec' and what isn't. I would also be curious to know if one could connect a second subwoofer to the rear-surround channel using a proper external crossover to dump anything above a given value (say 80-125Hz).
 

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Originally posted by Andrew_B
... By using the main left and right pre-outs to feed thge sub, you are getting the same information but you are just using a different route. ...
This is arguable. Using main left and right pre-outs, the receiver's crossover does not affect the LFE signal, all of which will be added in to the signals sent to the mains. Using the sub out, the receiver may be low-pass filtering the LFE signal, resulting in loss of a portion of the LFE above the receiver's crossover.


And of course using the mains pre-outs makes it possible for both the mains and the sub to play a portion of the bass frequency range, if the mains are driven directly by the receiver's amp.
 

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Quote:
Originally posted by WanMan
Well, now this brings up an interesting question regarding the integrated receiver or pre-pro processor in question. I would expect that the signal sent out the regular preouts to be full-range, but what about the subwoofer preout? Also, I cannot find for my AVR what frequency range is being sent out the the preouts, or rather what those preouts are capable of sending out.
Your LFE only contains LFE info, so 120hz and lower. Now if your reciever has a lower x-over point (say 100hz) then the LFE is only outputing those frequencies.
 
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