[a1p1]

I'm looking for advice on the construction of a dedicated audio room.  A few details:

The room will be 15'x25' on concrete slab; likely 9' ceilings.  Carpet, no windows.

Heating and cooling will be accomplished through an independent in-wall unit; think hotel unit. 

There will be no duct work connecting the room to the rest of the house.

The room will be connected to the garage and screened porch with exterior doors. It is not directly connected  to any other part of the house. 

2'x2'x9' rigid fiberglass "super chunk" bass traps in three of the four corners.  Rigid fiberglass traps at first reflection points.  More traps to be added.

 

Concerns: 

Door location: currently one door (to screened porch) is located in a rear corner, eliminating my ability to have a large super chunk bass trap.  How much of a problem is this?  I can move the door along its current wall, but it will make the door less useful (opening to a deck instead of screened porch).

Wall construction.  Is standard drywall and stud construction sufficient in this situation.  Should I consider a double layer of drywall?  Anything else?  I'll likely use can lighting in the ceiling.  My assumption is the room will be well isolated from the rest of the house given its location and lack of ductwork.  Is that a reasonable assumption?

Thanks in advance,

AP

[MaxCast]

Make 4 corner traps and slide it in front of the door to keep everyone out. 
Although I suspect 2x2x9 can be pretty heavy.

Check your first reflection points as I think they will be closer to the speakers, possibly on door to garage.

Don't forget to check out diffusion.

Congrats on a new dedicated room.

[a1p1]

MaxCast,
Thanks.  You are absolutely right about the first reflection points.  I've corrected the diagram and moved the door. 

AP

[Hipper]

I'd try without reflection points on the side walls first to see if you like the sound.

Floyd Toole in his book 'Sound Reproduction' thinks it's better. I tried it in my smaller room with a nearfield set up, and I agree! I reckon you get a more lively sound.

I should add that I live in the UK and we have brick walls.

[Red Dragon Audio]

AP,

Here are a few quick ideas...

• 2x6 Exterior wall construction to allow more insulation material inside wall cavity**
• Blown in cellulose insulation for walls (i.e. Nuwool)**
• Double drywall with Green Glue between sheets**
• Soffit style Bass Trap around upper perimeter of room
• Move Screen Porch door to garage side
• Area Rug to address 1st Reflection point from floor in front of listener position
• Two additional Acoustic Panels at 1st reflection points on Ceiling.
• Add two more absorption panels to side walls in order to have broader 1st reflection point control (so you can experiment with forward/backward position of listener chair)
• Solid soundproof door and isolation trim (reduce sound transmission between garage and listening room)
• Real Traps Diffusor Panels at the back of room
• Requisite Beverage Cooler kept in garage
• UPDATE: Added window to meet firecode.

**Improves Sound Isolation thus lowering noise floor of listening room.  Also improves insulation R-value in walls.



Here is a nicely done room

[rollo]

   WOWIE!!!!!!!!!!!!!!!!!!!  A lucky man.


charles
SMA

[a1p1]

Red Dragon Audio,
Thank you.  Several good tips.

The room must have a second door or a window to meet fire code, so I have to address that in some manner. 

The 6" walls with additional insulation sounds like a good idea for sound isolation and thermal insulation. 

Do have any additional info on a soffit bass trap; pics? plans?  Is there an advantage over other bass trapping?

Diffusion on the back wall should be possible; I will have a desk in the rear of the room. 

Kegerator will be in the garage. 

AP,

Here are a few quick ideas...

• 2x6 Exterior wall construction to allow more insulation material inside wall cavity**
• Blown in cellulose insulation for walls (i.e. Nuwool)**
• Double drywall with Green Glue between sheets**
• Soffit style Bass Trap around upper perimeter of room
• Move Screen Porch door to garage side
• Area Rug to address 1st Reflection point from floor in front of listener position
• Two additional Acoustic Panels at 1st reflection points on Ceiling.
• Add two more absorption panels to side walls in order to have broader 1st reflection point control (so you can experiment with forward/backward position of listener chair)
• Solid soundproof door and isolation trim (reduce sound transmission between garage and listening room)
• Real Traps Diffusor Panels at the back of room
• Requisite Beverage Cooler kept in garage

**Improves Sound Isolation thus lowering noise floor of listening room.  Also improves insulation R-value in walls.



Here is a nicely done room

[Red Dragon Audio]

Red Dragon Audio,
Thank you.  Several good tips.

The room must have a second door or a window to meet fire code, so I have to address that in some manner. 

The 6" walls with additional insulation sounds like a good idea for sound isolation and thermal insulation. 

Do have any additional info on a soffit bass trap; pics? plans?  Is there an advantage over other bass trapping?

Diffusion on the back wall should be possible; I will have a desk in the rear of the room. 

Kegerator will be in the garage.

Hi AP
I updated the room layout to include a window just behind the speakers - would that meet fire code?
It's less of an acoustic issue in that part of the room and some acoustic curtains could be drawn over the window if it's an issue.

GIK provides information and benefits regarding a Soffit Style Bass Trap.  See link and image below (that is an image from GIK's website).


-Ryan

http://www.gikacoustics.com/gik_soffit.html

[bpape]

I don't see a problem with the 2nd door - especially as currently shown.  In the rear corner, I wouldn't get too hung up about it. 

The seating position appears to be a bit far back to me for smoothest bass response.  This would also make diffusion on the rear wall more of a potential option.  You simply need a certain distance based on diffusion lower end to allow the diffusion to work and spread out appropriately in time and space. 

Double drywall is to provide more isolation from sound getting in and out.  In terms of in-room response, it will lower the resonant frequency of the walls and make them more rigid and less able to help absorb a bit of bass.  Kind of a tradeoff.

For the reflections, a lot depends on the off axis response of your speakers.  If they're pretty good off axis, you can potentially diffuse the side wall reflections.  Same goes for the ceiling reflections.

Bryan

[a1p1]

Thanks Bryan
I should have noted the speakers, GR Research/AV123 LS-9s.
My understanding is that I should try to sit at least 8 feet from the speakers; 10-12 even better. Ceiling reflections are evidentally less problematic with a line source of this size. So losing bass a bass trap in one rear corner is not a big compromise?
 
AP

[bpape]

You're fine in the rear corners.  The big decision is whether you need diffusion or bass control on the rear wall (many of the worst bass cancellations come off the back wall). 

Yes - I'm sure sitting farther away is what the speakers need.  That said, if that pushes you into a place with poor bass response, that doesn't help much.  I'd like to see you sitting no less than 8' from the wall behind you.  That still leaves 19' for some breathing room behind the 9's and a good distance from you to them for proper integration.

Bryan