[RichardDunn]

Hello!


I have an oddly shaped room that I am planning on turning into a theater. I am in the process of deciding what to do about HVAC. I am looking into a mini-split system and I need to know if I have to divide my oddly shaped room up into two rooms or will it be OK to remain as is. If I have to go the two room route, obviously this will increase HVAC costs because I'll have to get two indoor units.


The large room is approx 16' X 23' and the smaller room off to the side is 10' X 15'. The room is located in the garage rafters, so it is about 8' tall in the flat center and the ceiling slopes down at the side to about 4' walls.


If I leave the room as is, will I be dealing with acoustic problems that cannot be fixed by acoustic panels, bass traps, or speaker placement? IS this waaaay too little information to answer the question?

Thanks!

Visio-ManCave.pdf 24k .pdf file

 

[HopefulFred]

Richard, welcome to the madness.

I would prefer to seal it off. Two reasons: Coupled spaces and bass decay can be very weird; and stereo imaging.


Looking at your layout, I see two room connected by a short corridor. Each space will have its own resonances in the bass range - this is true no matter the shape or proportion of a home space. What's unusual (for dedicated spaces anyway) about your scenario is that the resonances of one space will interact with the resonances of the other space, because they are linked. Energy in one room will ring, exciting a ringing in the other room (probably at a slightly shift frequency), and that energy will bleed back into the theater - but significantly delayed, and maybe shifted in frequency to boot. That can make for some really weird bass ringing. Can this be fixed by absorption? Sure. How much would it take? Probably more than makes since, IMO.


If the coupled space were behind the listening position, it might make some since to try and absorb your way out of the problem, but you won't be able to absorb your way out of a missing right lateral reflection. In theory, broadband absorption to the left of the listening position could absorb the energy there and thereby mimic the acoustic hole created by the missing portion of wall on the right, but the reality is that effective absorption at that position is never going to be effective enough... It's much better for a stable and centered stereo image to have symmetrical walls (and loudspeaker layout, and seating) - at least in front of the listening position. Asymmetry behind the listening position would be much less obvious.


Obviously, the costs to building the wall and presumable installing a door are real, and extra costs for ventilation are probably non-trivial, but the acoustic costs of the room in your diagram are real too. Certainly your priorities don't have to match mine, but that's where I stand. Maybe you can find a way to only use one HVAC unit? What are the pans for the smaller space?


Fred

 

[RichardDunn]

Thanks so much for the quick reply, Fred!


I was thinking of making the smaller room into a two channel listening room. Sounds like if I were to not wall off the two rooms that there would be negative acoustic effects in the smaller room as well.


The lobe on the left hand side of the diagram is a window alcove. I do intend to make a plug for the window to block the glass from sending any reflections back into the room. If a was to place a wall on the right side of the room, should I make an equally sized lobe on the right side? For symmetry?


Thanks!

 

[HopefulFred]



Quote:
Originally Posted by RichardDunn  /t/1523206/oddly-shaped-room-acoustics#post_24501274


should I make an equally sized lobe on the right side? For symmetry?

I think that's a nice goal, but don't get bogged down in a few inches here or there.