Listening room measurements / How'd you do it?

[pearsall001]

I presently have a GIK monster bass trap & two Echo busters corner traps. The difference they made was quite noticable. I want to take it further w/ more absorption panels, bass traps, diffusion panels, etc. but first I'd like to measure my room's acoustics. With room measurements I can then decide on a plan of action. Did any of you guys do this & if you did how did you do it? I'm not very savy with this sort of thing. Hopefully the simpler the better.

[dyazdani]

There are several ways to do this - they all require a measurement instrument, the most common is a SPL meter from say, Radio Shack.

The "lower tech" way is to get a disc of test tones and a sheet of paper and write down the SPL as you go through the tracks. I usually just make a graph in Excel after I write everything down.

The easier way to do it (labor-wise) is to use your computer. I use RoomEQ Wizard (free) - you hook your SPL meter to your computer and it takes measurements for you. There are other RTA programs available, but I think most cost money to get a useful version.

Let me know what sounds good to you and I can give you more info. I think ThomasW on the forum has some good info compiled on the use of RoomEQ Wizard.

[pearsall001]

Danish,

Thanks for the info. Awhile ago I purchased the Rives Audio Test CD2 for mapping my room response. I played around with it but didn't get to far. For example it says to play a test tone at 1000 Hz & 4000Hz & adjust the volumn until it reads 0 on the meter to get a mid point. I have a digital RatShack SPL meter so would I set it to 80 which would be 0 on an analog meter? If that's correct I think I can fire it up again & graph it correctly. I'll check out the other items you mentioned. I'm actually getting better at this stuff. Any other ideas would be well received.

Cheers,
Phil

[dyazdani]

Yes, I'd set it around 75-80 as the reference point. I usually wear earplugs through the whole process. The tones drive me crazy after a while.

What is the resolution on the Rives CD? i.e. how far apart is each frequency? You miss a lot of peaks and valleys if it's not fine enough. I made a test CD that has tones 1Hz apart from 10-300 or something. I took around an hour or hour and a half to run through them.

I like the computer now because you can kick off the tones and let it run on it's own.

[pearsall001]

Here's a quick sample of some of the frequency ranges. Each tone plays for about 10 seconds then jumps to the next frequency.
20-25-31.5-40-50-63-80-100-125-160-200-250-315-400-500 all the way up to 20K. They seem pretty far apart don't they. Is this even worth charting or are they pretty good?

Phil

[dyazdani]

Those are 1/3 octave spacings I think. You won't see a whole lot with those frequencies IMO. The link below will point you to the tones that I used, 10-300Hz in 1Hz steps. If you want to do higher frequencies, perhaps you can Google for something similar.

Test Tone Link

[pearsall001]

Danish,

Thanks a bunch!!!

Phil