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Stereo vs summed to mono for Subwoofers [message #28282]

Wed, 08 August 2007 14:16

granch
Messages: 118
Registered: May 2009

Viscount

Given two or more subwoofers in a stereo system, what difference, if any, will there be between connecting the subwoofers in stereo or summing the channels to mono and feeding that signal to both subs? I have a little experience with this but not much and would appreciate any words of wisdom. Would it make a difference to the answer if the two subs were colocated or located with each stereo channel. I have only tried it colocated and not noticed any difference. I can think of arguments on either side, but I need practical advice.
Dick

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Re: Stereo vs summed to mono for Subwoofers [message #28283 is a reply to message #28282]

Thu, 09 August 2007 11:01

Bill Wassilak
Messages: 402
Registered: May 2009

Illuminati (1st Degree)

Dosen't really matter, if your crossing over at less than 100HZ. Bass and kick drum on most recordings is recorded in mono anyway.

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Re: Stereo vs summed to mono for Subwoofers [message #28284 is a reply to message #28283]

Thu, 09 August 2007 11:59

granch
Messages: 118
Registered: May 2009

Viscount

I'm not much concerned with recordings. Its organ mostly. I know that if the channels are separate they can acoustically cancel each other at times in some spots. But if you sum first you are going to produce occasional cancelations everywhere. Interesting to know the recording industry does that. I wonder if they do it on symphony and other classical music as well?
Dick

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Group together outdoors, spread around indoors [message #28288 is a reply to message #28284]

Fri, 05 October 2007 23:43

Wayne Parham
Messages: 18790
Registered: January 2001

Illuminati (33rd Degree)

The best placement for subs depends on where you are.

If outdoors or in a very large indoor arena, group the subwoofers together. If you can keep them close enough together (within 1/4λ), they'll act as a single acoustic source.

If indoors, spread them around to average the effect of room modes. Reflections make virtual sources that cause unavoidable cancellation nodes. But by spreading the subs, you can make the interference so dense that it tends to average the sound field throughout the room.

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Re: Group together outdoors, spread around indoors [message #28289 is a reply to message #28288]

Sat, 06 October 2007 00:18

granch
Messages: 118
Registered: May 2009

Viscount

Makes excellent sense. Thank you. I intend to follow it outdoors. Inside I have a very unusual room. Like an isoscelese triangle with the organ along the base. The corner (90 degree) opposite the base I have 4 HSO subwooofers. two regular, two mounted facing each other vertically. Works great all over the place. This is only an approximation. The whole house is a 32 ft sguare. A large fireplace (stone) sort of diagonally bisects the square with the organ wrapped around 3 sides of the fireplace wall. I think I posted a pix once upon a time. Anyhow the only location that seems to make sense for the subs is in that corner, and it does shake the whole house very thoroughly. Must keep all crystal glasses well separated from each other.
-Dick

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Re: Group together outdoors, spread around indoors [message #28290 is a reply to message #28289]

Sat, 06 October 2007 10:08

Wayne Parham
Messages: 18790
Registered: January 2001

Illuminati (33rd Degree)

Have you ever seen CARA? I can't remember if we talked about it already, but I post something about it from time to time. You might use CARA it to analyze your room and see the energy distribution. It will show you hot spots and dead spots at various places within the room. You can try different speaker placements and see how that affects energy distribution.

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Re: Group together outdoors, spread around indoors [message #28291 is a reply to message #28290]

Sat, 06 October 2007 18:11

granch
Messages: 118
Registered: May 2009

Viscount

Thanks for the suggestion, For now I'm happy with what I have. I also have two AR-9's, one on each side of the organ console. These provide in-house reverb for the organ and carry the main stereo stuff when playing CD's or whatever. The subs are used for both the organ pedal and for use with the AR-9's - which is over doing it somewhat, but nothing succeeds like excess. The main entertainment system is in the next room (also a triangle, sort of) with a Bose (5.1) system that is almost exclusively used for the sound from a 60" HDTV. I used to sprinkle some AR2's and 3's around the house at some distance from the organ driven along with the AR-9's to aid in the reverb effect. It really wasn't worth it so we now use them for other purposes.
-Dick

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Re: Group together outdoors, spread around indoors [message #28292 is a reply to message #28291]

Sun, 07 October 2007 12:02

Wayne Parham
Messages: 18790
Registered: January 2001

Illuminati (33rd Degree)

Sounds like you have a very good setup. I like to recommend CARA because I've found it to be very useful, and it isn't expensive. But I think maybe in your case, it would just be an interesting pastime, and you'd get to see the energy distribution in your room. You'd probably find out what you already know, that the room layout is optimal.

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Re: Group together outdoors, spread around indoors [message #28293 is a reply to message #28292]

Sun, 07 October 2007 20:09

granch
Messages: 118
Registered: May 2009

Viscount

Well, it may be optimal, but it's also about the only way to do it.Getting all my stuff into a housed this small is an exercise all ny itself. I'll add your suggestion to my 'to-do list' but it won't be high priority.
-Dick

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