Room acoustics

@toddverrone

I rotated my 3D plot so you can see well the time axis. Your time axis comes almost straight out of the page...


Here is a good resource.

http://www.bobgolds.com/RT60/rt60.htm



It has a table at the bottm of the page specifying recommended control room RT60 as a function of room volume. This is a fairly dead control room and the specifcation can be relaxed below 200 Hz and audiophiles will probably prefer something higher or more lively (up to double in RT60 specified)

Key takeaway is that SMALL rooms require gargantuan amounts of absorption treatment!!!!!!! A shower stall is terrible except to sing to yourself....

V in ft^3 V in m^3 ITU RT60
63 1.8 0.07 (shower stall - waterproof acoustical treatment required?)
1000 28.3 0.16
1250 35.4 0.18
1500 42.5 0.19
1750 49.6 0.20 (approximately 16’ x 16’ x 7’)
2000 56.6 0.21
2250 63.7 0.22
2500 70.8 0.22
2750 77.9 0.23
3000 85.0 0.24
3250 92.0 0.24
3500 99.1 0.25
3750 106.2 0.26
4000 113.3 0.26
4250 120.3 0.27
4500 127.4 0.27
4750 134.5 0.28
5000 141.6 0.28
5250 148.7 0.29
5500 155.7 0.29
5750 162.8 0.29
6000 169.9 0.30
6250 177.0 0.30
6500 184.1 0.31
6750 191.1 0.31
7000 198.2 0.31
7250 205.3 0.32
7500 212.4 0.32
7750 219.5 0.32
8000 226.5 0.33
8250 233.6 0.33
8500 240.7 0.34
8750 247.8 0.34
9000 254.9 0.34
9250 261.9 0.34
9500 269.0 0.35
9750 276.1 0.35
10000 283.2 0.35
11000 311.5 0.37
12000 339.8 0.38
13000 368.1 0.39
14000 396.4 0.40
15000 424.8 0.40
16000 453.1 0.41
17000 481.4 0.42
18000 509.7 0.43
19000 538.0 0.44
20000 566.3 0.45
22500 637.1 0.46
25000 707.9 0.48
27500 778.7 0.50
30000 849.5 0.51
32500 920.3 0.52
35000 991.1 0.54
37500 1061.9 0.55
40000 1132.7 0.56
50000 1415.8 0.60

Sweet Lord, that post will take a while to decipher. Thanks!

I just wanted to post back that my first limp membrane absorber is a smashing success. It's very deep (14") but only 10" wide and 16" tall. It's like a good size monitor speaker cabinet. I used thick vinyl for hot tub covers and used polyurethane caulk to glue two layers together, as an increase in membrane density helps to lower the effective frequencies the absorber works on.

I'll post graphs later, as I'm about to head out to dinner, but, subjectively, my 3 note bass problem is, if not gone, greatly reduced. Objectively, I have almost all bass frequencies dropping below 40db by 300ms. 

This is good fun. Sorry I seem to be the only one posting questions on this thread. I definitely appreciate your input, @s

Sorry, @shadorne