Dual Sub positioning

[Reorx]

I have a massive open room (family, office, dining) that I have setup for my HT.
Over 8000 ft^3. 13-14k ft^3 if I count the kitchen and hallways.
I know I am supposed to place subs symmetrically from each other.
The only symmetrical options I have are front left, and back right corners...or both up front.
The Back Right sub would replace the decorative table, below the mirror.

Question: How disruptive will the 2ft wall partition be to the bass waves?
fyi, I do not have replacement subs picked out yet.

Thank you.

 

[WaynePflughaupt]

You really can’t achieve symmetrical placement in your situation. That requires a symmetrical room with “shoebox” dimensions. True symmetrical placement would mean say, both in two front corners of such a room.

Subs generally get the best performance at or near a corner with uninterrupted walls in both directions. So your rear location, with the open doorway only a few feet from the corner, won’t get great results.

I did some experimenting with catty-cornered subs in a symmetrical room, like you’re proposing, and the measurements were absolutely abysmal.

I’d recommend stacking them both in the front left corner.

P.S. Nice choice on the Ashly amp. They don't get much attention on the home audio forums, but I've always heard from pro audio guys that they were great amps.

Regards,
Wayne A. Pflughaupt

 

[ImcLoud]

I would put one left of the tv and one right, tuning them separately, I noticed I have yet to set up the x.2 system where the gains matched.... I currently have 3 2.2's and 1 5.2 in my house and I LOVE dual sub setups, it is like night and day over a single sub...

 

[Reorx]

Thank you both for the replies.

WaynePflughaupt, I think the challenge with that option is room acoustics. I have 1 there right now, and I have nodes/nulls all over the place. If I double up the subs in that corner, I would expect it to get worse. I love my ashly amp. It's fan is a little loud, but when content is playing, it's fine. I use it to power my JBL speaker/sub. When I buy new sub's, I will move that amp to my left and right speakers.

ImcLoud, I thought about that, and it was my 1st thought, but didn't know how the 1/4 wall, corner, and vaulted ceilings would play into the acoustics.

This room/house is an acoustic mess. I have bass from my 1 sub rocking almost every room in the house, and a gramma didn't help.
I am probably going to talk to GIK and see what options they provide, short of buying a new house.

Reorx

 

[KEW]

I’d recommend stacking them both in the front left corner.

Wayne, I am surprised at this suggestion. Are you suggesting he co-locate them? would not that give up the dual subs' ability to smooth out nulls and nodes?

 

[WaynePflughaupt]

Hey Kurt,

Most of the material I’ve seen advocating for multiple spread out subs performed their experiments and documentation in rooms with symmetrical dimensions – “shoebox” rooms. In these rooms, modes and nulls are predictable.

All that goes out the window when you have an asymmetrical room, and especially one that’s “open concept” like the OP’s. Modes and nulls are totally unpredictable, meaning there is no “room mode calculator” that can tell you at what frequency they will occur.

Here, other factors come into play. For instance, we know that a sub will get the best output and extension in a corner with uninterrupted walls in both directions (i.e. no openings). Given the OP’s room as an example and assuming identical subs, if we put one in the corner and one behind the couch, the latter will have significantly reduced output and extension (in addition to exhibiting abysmal frequency response overall, but we’ll put that aside for now).

What you will end up with is the same scenario you see where people try to utilize highly capable and mediocre subs in the same room: Overall bass performance is ultimately “dumbed down” to that of the lesser-performing sub, as can be seen here, with graphs to prove it.

So – that’s why I recommended putting both subs in the same corner. Personally I’ve never lived in a place wasn’t “open concept,” and in every one I got the best results with corner placement.

On top of that, we don’t know what the OP’s frame of reference is when he claims he has “modes and nulls all over the place” with the sub in the corner, and he’s provided no frequency response graphs for us to evaluate and determine whether or not his perceptions are correct or accurate. Both places I’ve lived in after adding subs to my system were very similar to what the OP shows us in his picture – open concept, vaulted-ceiling with seating in the middle of the floor (i.e. away from any boundaries), and with co-located subs proper equalized, bass performance was superb. And on top of that, audibly consistent for any seat in the room that wasn’t near a boundary.

Regards,
Wayne A. Pflughaupt

 

[lsiberian]

Thank you both for the replies.

WaynePflughaupt, I think the challenge with that option is room acoustics. I have 1 there right now, and I have nodes/nulls all over the place. If I double up the subs in that corner, I would expect it to get worse. I love my ashly amp. It's fan is a little loud, but when content is playing, it's fine. I use it to power my JBL speaker/sub. When I buy new sub's, I will move that amp to my left and right speakers.

ImcLoud, I thought about that, and it was my 1st thought, but didn't know how the 1/4 wall, corner, and vaulted ceilings would play into the acoustics.

This room/house is an acoustic mess. I have bass from my 1 sub rocking almost every room in the house, and a gramma didn't help.
I am probably going to talk to GIK and see what options they provide, short of buying a new house.

Reorx

Did you do a crawl test? You need to do that and mark the two best spots. Once you have them move the subs there.

 

[mojogoes]

Wow what a room!! Nice though........But you've got your work cut out for you there for sure! With all those archway doors and extended room spaces.

 

[Reorx]

Thank you all for the responses.

I do not have full measurements for my room. It is on my to do list once I buy a microphone.
But when playing bass sweeps you can walk around and hear the modes. The only bass mgmt I have is in my receiver. My amp has nothing available except volume.

I have not done the subwoofer crawl. My current 'sub' is not a traditional sub. It is a pro concert speaker. The construction is different. I can always try it. It wouldn't hurt.