What is needed to measure room acoustics?

[roll - gybe]

Hi all, I am interested to measure the acoustics of my living room. It is very large and cavernous. When we talk from opposite sides of the space, it can be hard to understand each other.

I think I would like to pursue some treatments, but I am interested in how the room measures out.

What gear do I need (my computers run vista) and how much does it cost?

This might be a nice primer for AH to put together.

Thanks in advance, guys.

 

[Midcow2]

SPL meter

SPL (Sound pressure Level) meter. Usually the analog and digital have about the same accuracy one dispalys digital and one displays analog. Your preference.

Radio Shack digital $49.99
http://www.radioshack.com/product/index.jsp?productId=2103667&cp=&sr=1&origkw=SPL&kw=spl&parentPage=search

Radio Shack analog meter $44.99
http://www.radioshack.com/product/index.jsp?productId=2103668&cp=&sr=1&origkw=sound+level+meter&kw=sound+level+meter&parentPage=search

There are other sources Google for "Sound Pressure Level Meter"

 

[trnqk7]

I think he might be referring to frequency response graphs and the like...which he can make his own with a spl meter if he has a test tone cd and cares to record all the values.

So a cd/dvd with test tones
SPL meter
Excel/OpenOffice/whatever spreadsheet app you like

You can then do this from multiple listening positions to see how placement and seating positions affect the sound you hear. Could be interesting...will help you pick out dips and peaks across the frequency band.

Then, ask about what room treaments would help fix those-there are several on here that have good ideas about those things.

 

[roll - gybe]

so are you suggesting taking hand readings and plotting them like in a high school science lab?

which is fine, but i'm just trying to understand the specifics...

 

[no. 5]

REW is fantastic freeware. You will need a measurement microphone and a way to plug it into your sound card.

 

[fredk]

I believe you can use the radioshack meter with rew as well. THere are correction files for it so you get more accurate measurements outside its specified range.

 

[Weasel9992]

REW is fantastic freeware. You will need a measurement microphone and a way to plug it into your sound card.

There you go...that ought to give you a fair representation of what's going on in the room. What you actually *do* about it is whole other discussion

Frank
GIK Acoustics

 

[roll - gybe]

I have seen the REW in a few posts. I checked out their website, and I am still not sure what exactly I need to run the software.

You mention a microphone - what kind of microphone?
Then I just plug it into the sound card on my laptop, and it gives me data? Do I need a test tones disc or anything? Or do I just play more Steely Dan?

Sorry to be so remedial about all this. I guess you have to learn somehow.

 

[Weasel9992]

I have seen the REW in a few posts. I checked out their website, and I am still not sure what exactly I need to run the software.

A microphone, a soundcard and a computer that can run the software.

You mention a microphone - what kind of microphone?
Then I just plug it into the sound card on my laptop, and it gives me data? Do I need a test tones disc or anything? Or do I just play more Steely Dan?

Ideally it would be as neutral a mic as you can find; not a vintage tube mic or something. You'll need some test tones:

http://homerecording.about.com/od/homestudiobasics/a/test_tones.htm
http://3d2f.com/tags/test/tone/wav/files/
http://www.softpile.com/Utilities/Password_Recovery/Review_10205_index.html

There are literally dozens of sites to download test tone generators from...just thought I'd include a few.

The site where you download REW should give you some pretty detailed instructions. Post the waterfall chart when you get it.

Frank

 

[no. 5]

You mention a microphone - what kind of microphone?
Then I just plug it into the sound card on my laptop, and it gives me data? Do I need a test tones disc or anything? Or do I just play more Steely Dan?

To add to what Frank said, I use a Behringer ECM8000 for a microphone, but like FredK said, you can use a Radio Shack or Galaxy Audio SPL meter (I have used the RS meter before, and it is easer to connect than the ECM8000).

You need to plug the mic into the soundcard's input, and you need to plug the soundcard's output to your stereo, REW will create and measure test tones.

The REW forum at The Home Theater Shack should provide all the information you'll need.

 

[moggi1964]

The Rives test CD will give you the tones you need.

I am planning to run REW with the RS SPL meter and the Rives hooked up to my laptop..

 

[bpape]

If you use REW with the Radio Shack meter, you can use a mic calibration file to compensate for the innacuracies of the mic. At this point, you're not looking for perfect and the 8000 would be better but the Shack meter will be something that can be used for less money and for other things - like balancing channels, setting absolute SPL to the REW tool, etc.

Bryan