sub placement and retrofit suggestions

[kenhoeve]

I am placing a--
Velodyne spl-1000r front firing long excursion sealed (1000W RMS)
crossed over at 80hz via AVR

I have little placement choice for my sub so I am planning to place it on the floor beneath a niche cabinet that I am installing. This location is almost directly beneath the TV but behind a wall and about 10' in front of the listening position. Pics should help visualize

Niche is in the foreground, as you can see there is a firebox in there.

This is where it is looking from the couch. The niche is on the right, so the sub is lower right of TV.

Looking at the niche.

So the sub will actually be below the cabinet. I plan on installing a grille in the wall to vent the sub space. My questions are

1. Is this even remotely a good position?
2. Is placing this in the same space as a firebox a recipe for resonating disaster?
3. Can I retrofit some acoustical insulation around the sub to improve both sound and resonation properties?

 

[bpape]

Building any speaker, sub or not, into a wall if not designed to be there is not a good idea.

Bryan

 

[kenhoeve]

don't everybody chime in all at once now.

I got the receiver set up and watched one of the lord of the rings last night using the Audyssey EQ setup. All I can say is

The sub is performing very well where it is at so it is staying. The only question I have now is simple then; what is the best way to retrofit the space beneath the cabinet where the sub will be? Do I box it in with acoustical insulation on three sides and vent to the front, or do I just insulate to the rear and vent the front? Does it matter which way the sub faces?

 

[kenhoeve]

Building any speaker, sub or not, into a wall if not designed to be there is not a good idea.

Bryan

I have no other place to put it, none.

So how can I make the best of it?

 

[kenhoeve]

I am begging for some advice here. If you look at the cable tuner in the first pic, the sub is placed under that. And oh by the way I swapped out my sub for a bigger one(velodyne spl 1000r) so this is even more important.

First, I am planning on cutting two 6x12 holes in the drywall below the cable tuner. I'll place passive HVAC grilles over them. The sub is front firing toward them so I somehow think this has to be a good idea.

Second, I need to deaden up that firebox somehow. If I press on it, I can get rid of a lot of the resonation. This makes me think if I pad it with dynamat or something, it might help. Suggestions please. BTW, the firebox is a "cool" unit only requiring 1/2" clearance.

Third, I'm thinking of somehow blocking off the space that the sub is in from the space the firebox is in. Probably with some 1/2" ply and acoustic insulation.

Anyone have a clue if any of this stuff is a good idea, or if I should do things differently?

 

[kenhoeve]

just in case somebody ever looks at this thread, here are some answers I got after consulting Tweeter and Velodyne.

Deadening the firebox:
1. dynamat makes a material suitable for high temperature, used that to cover the face of the box facing the sub.
2. using insulation and straps, i tightened up the flue in 3 positions up to the next floor.

Enclosing the sub:
1. Velodynes can be used in closed cabinet situations per manual.
2. Subs move air, it is wise to leave it open to as much air as possible.

Grilles:
1. I cut a hole large enough to remove the sub through the wall using a 16"x16" hole. Custom made doors with fabric for fascia.

Positioning:
1. Maybe it isn't the best, bet articulating the unit to bounce off an adjacent wall to the listening position is the best you can do. Placing something smooth as a reflection point is a good idea.