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Ever hear of stacking subwoofers?

740 Views 8 Replies 6 Participants Last post by  avdoc
In the ongoing dialogue concerning the need or desire for multiple subwoofers, the question of placement inevitably gets raised. Although I've certainly heard that placing subwoofers in the same general locale is not only normal, but probably preferable, this is one I'd not heard of: stacking subwoofers.

What's more, the method of stacking them struck me as odd too: placing the second sub upside down, so that the drivers of the two subs are as close together as they might possibly be.

This came straight from Veldyne's product department. I'd be interested to hear if anyone has any experience with subs like this.
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I have tried this exact scenario (among many others) you describe with a pair of M&K 350THXs. It actually works quite well and basically doubles the output. However, I get smoother and more balanced sound with my two subs placed in each rear corner behind me. Although, I could go balls out like Steve and aquire two more units to then stack them. http://www.avsforum.com/ubb/wink.gif
Interesting. My room configuration would not permit me to try subs behind me (long story--long room).

Deniz, did you invert the second sub, as described?

What did you use for isolation between the two?

I assume volume, crossover, etc. were set identically?
I did invert the sub as you mentioned and the xover and gain was set by my processor to identical values.

For isolation I use 1/8" thick strips of Sorbathane in all four corners. I buy this in 12" x 12" sheets, and also use it to isolate the satalite portion of my towers from the bass section.

BTW, I also placed the sub in its normal position (upright) because of the driver config with its two 12s and didn't notice a difference.

[This message has been edited by Deniz Mutlu (edited July 01, 2000).]
I stack 3 THX Subs next to my Mits 65905

Heres some Pic's of the setup


Where do you purchase sorbothane sheets and what is the price?

I'm a Sorbathane dealer. I really don't remember what I paid for it but it is relatively inexpensive.
actually, stacking the subs is recommended by Boston Acoustics for their 595x subs... i have tried them in both separate locations and stacked and have to say that stacking provides a much tighter and more defined bass...
Stacking is a common practice in maximizing subwoofer output. This is because placing more than one sub in a room invites some very nasty interactions between subs. These interactions are avoided by placing the subs in the same location. Unless you have a real-time analyzer and the appropriate software, stacking subs is your best bet for maximizing performance. It is virtually impossible to properly place two subwoofers in a room using only a SPL meter and test disc (although you're welcome to try, I recommend a dolly and weight-lifting belt). However, don't think that stacking two subs will not give you twice as much output. You will normally only see a gain of about 3 dB or so.
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