Large room, minimal budget

Hello. I'm building out a 2-channel listening space in my detached garage. Dimensions are essentially 23' x 23' x 8' with a slightly sloping floor.

I'm planning to use the garage doors as the front wall.

I built a bunch of panels before using OC 704 panels wrapped in 1x4's held 4" off the walls (at reflection points). In a space this large, I'm thinking I might need full soffit treatments.

Can someone point me to a good resource on where to start? I'll likely need to go the DIY route to manage the budget as I could easily see proper treatments from manufacturers running me into the $20k range.

GIK has plenty of statical information and testing data of their various acoustic treatment devices... The Master Handbook of Acoustics by F. Alton Everest and Ken C. Pohlmann has nice coverage of various acoustic treatment devices... You may be able to find a copy of a previous edition as a pdf on the internet...

Also, http://arqen.com/bass-traps-101/placement-guide/ covers some things that may help you...

You might consider some form of Room Correction DSP after you get close with your physical absorption and diffusion...

PS - A square room is not a great place to start from...

GIK will also help you, and I don't think you'll be anywhere near even half of $20k. I could see spending a few thousand, but the main idea will be to eliminate the echo in the room. Carpet, chairs, corner bass traps, maybe a few panels overhead since the ceiling is fairly low.

If I remember correctly, the Quad speakers are fairly direct, so there shouldn't be too many side reflections from the walls. They are similar to my MartinLogans and RTJ horns—very direct. Your main issue may be from 150Hz and below, the area that is harder to tame with acoustic panels, especially below 100Hz.

kdubious said:

Hello. I'm building out a 2-channel listening space in my detached garage. Dimensions are essentially 23' x 23' x 8' with a slightly sloping floor.

I'm planning to use the garage doors as the front wall.

I built a bunch of panels before using OC 704 panels wrapped in 1x4's held 4" off the walls (at reflection points). In a space this large, I'm thinking I might need full soffit treatments.

Can someone point me to a good resource on where to start? I'll likely need to go the DIY route to manage the budget as I could easily see proper treatments from manufacturers running me into the $20k range.

Click to expand...

the square nature of the room might be a bit of a challenge, acoustically speaking. You might consider looking into making it more rectangular?

Or... start at one end and make it narrower to the other end... 19' on one end... angled to 23' on the other end.

Interesting idea. because you have a 23x23 room... that's a large space, and a blank canvas!

Sonnie, if you were to partition a room like that, how would you attack the wall from a materials perspective?

There are a few options, I think. The old-fashioned 2x4 stud walls with sheetrock. You could get creative and make them somewhat of a Helmholtz resonator-type wall. Leave an opening of a foot or two along the walls, then stuff them with insulation. However, it's hard to know how effective this would be or where the openings would be best placed without testing it.

Probably best to frame the entire walls, stuff them with insulation, and do some testing. This effectively makes the wall a huge acoustic panel, although it may cause the room to be too dead if you leave the entirety of both walls open, but you could listen and get an idea pretty easily. You could also screw a couple of sheets of sheetrock to the walls with a limited amount of screws so you could easily remove it, leave an opening or two, and test it, then close up one of the openings, test it again. Then, decide if some or all of the walls could be covered with GOM material.

Breaking up the wall with openings sounds like it would help with room modes, but that's just a hunch... as I'm not an acoustical engineer, nor did I stay at the Holiday Inn last night.

I *could* possibly build in a closet (rectangular) in one corner, converting my square into 2 connected rectangles.

There are windows on the side walls. On one wall, I could build a closet that's 5' x anything less than 23. On the other side wall, the window is only about 30" off the back wall.

Does the closet idea make sense?

That would definitely narrow it up, but you also might consider leaving an opening of about 2 feet that you can test to see if it helps with room modes. If it doesn't, you could close it off and finish it. If it does, you could cover it with GOM material.

You might play with REW room sim... Plug in your room dimensions and have a look at where you will have your room modes...
Or try https://amcoustics.com/tools/amroc?l=23&w=18&h=8&ft=true&r60=0.6... Try a width of 17 or 19 and length of maybe 21 or 22... See what happens to the room modes... Hint... Less modes below the Schroeder frequency is usually better...

BTW there is an entire chapter in that Master Handbook of Acoustics that discusses how room size and shape affects small room acoustics...