Manifold Vented to Underneath Couch?

[tinnears]

This isn't really IB but...

I'm having a small cabin built on piers so there's lots of space under the first floor to mount a very large box to house a couple of 18 inch subwoofers. This will easily allow a QTc of .6 and Fc of 24Hz with the drivers I have in mind. I'll use a little EQ if need be. These will play from 10-35Hz just to supplement the lowest octaves. I'll have multiple 8 inch subs to place in various positions in the room which will play from ~35-80Hz.

What are the good and bad facts about venting the subs under the couch? I don't want a kidney massage and I doubt I'll ever again have a girlfriend so this may be a bad idea.

Your thoughts, please.

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I'm starting a separate thread asking about a completely different installation type... I don't want to convolute this thread.

[ThomasW]

The sofa will function as a bass trap, absorbing a good amount of output. Exactly how much I don't know.

[tinnears]

Hmm... okay. Thanks Thomas. I'm a novice and hadn't considered that. What if I opt for a futon instead?

Sorry this is off-topic for the forum but...

Another option is to build a really big coffee table to house the two subwoofers in separate sealed enclosures. The table could be approx. 1.5Hx2Dx7L for a net internal volume of approx. 9 ft^3 per driver after bracing and stuffing. This raises my QTc to just under .7 (on paper). I prefer higher damping but .7 is fine. I don't want a bigger coffee table than that. LOL!!

BTW, the drivers are Ascendant Audio AVA 18's.

[ThomasW]

Aug 3, 2012 12:06:09 GMT -7 tinnears said:

Hmm... okay. Thanks Thomas. I'm a novice and hadn't considered that. What if I opt for a futon instead?

It will also function as a bass trap but less of one than a sofa.

Another option is to build a really big coffee table to house the two subwoofers in separate sealed enclosures. The table could be approx. 1.5Hx2Dx7L for a net internal volume of approx. 9 ft^3 per driver after bracing and stuffing. This raises my QTc to just under .7 (on paper). I prefer higher damping but .7 is fine. I don't want a bigger coffee table than that. LOL!!

It would work provided you have access to a forklift in order to move it.

IMO a better option if you want to control the "Q" is to build a pair of smallish sealed boxes (use a removable single piece of material as the table top). Finally use a Linkwitz Transform circuit to lower the "Q" to the desired level.

[tinnears]

You mean similar to a Bag End subwoofer design?

Would a parametric EQ, infrasonic cut-off filter (5Hz), and crossover serve to replace the Linkwitz Transform circuit? I'm intending on using those anyway.

[ThomasW]

home.comcast.net/~thomasw-2/SubwooferSetupandEQpageDEQ2496-LT.html

[tinnears]

Thomas... Excellent!! I'm intending on using a Behringer DCX in this system and probably a DEQ also if the DCX can't quite fully fill all EQ functions.