[oneinthepipe]

I played Ethan's pink noise file to locate booming.  There was an increase in boom in the tri-corners, which I expected.  There was also an increase in boom behind and along the sides of the speakers.  I was expecting increased boom between the speakers and the side walls, but I didn't expect increased boom on the interior sides of the speakers.

I moved the speakers a few more inches from the front wall, and the boom in the corners seemed less, but the boom along the interior sides of the speakers didn't seem to decrease.  There are 6" thick OC703 panels behind the speakers.  When I placed 6" thick OC703 panels next to the speakers on the side walls, the boom in that location seemed to decrease slightly. 

I ordered a Behringer 8000 microphone, which should be delivered tomorrow, and if I can figure out connecting the microphone to my computer (I don't know what type of cable that I will need) and the calibration, I will run the test tones.

[bunnyma357]

Behringer ECM 8000 needs an XLR, and it also needs 48v phantom power, so you may need an audio interface that has phantom power (I have a USB Fast Track Pro and a Firewire Focusrite Saffire 26). You could also use a mixer like the Behringer Xenyx 802 going line in to the computer.

Jim C


edit: (Changed Mixer Model to 802, since it looks like the 502 I initially suggested doesn't have phantom power)

[TomS]

I just use the M-Audio MobilePre USB with the Behringer mic.  It provides the 48vdc phantom power needed plus 2 channels in and out with input level controls on the front.  Seems to work fine with most measuring software - REW (XP), Fuzzmeasure (Mac), etc.

[oneinthepipe]

Could I use one of these for phantom power and usb connection?

Blue Icicle

http://store.apple.com/us/product/TV233LL/A

MXL Mic Mate

http://pro-audio.musiciansfriend.com/product/MXL-Mic-Mate-XLR-to-USB-Mic-Interface-WPhantom-Power?sku=270707

OSP USB Adapter

http://www.siglermusiconline.com/store/pc/OSP-USB-Microphone-Adapter-w-Phantom-Power-36p1479.htm

Also, here is a Behringer phantom power supply for $20.00:

http://www.amazon.com/Behringer-Ultra-Compact-Phantom-Supply-PS400/dp/B000FG795I/ref=sr_1_1?ie=UTF8&s=musical-instruments&qid=1248322192&sr=1-1

[Ethan Winer]

Yes, it looks like any of those USB microphone adapters would be fine.

--Ethan

[oneinthepipe]

I have the Behringer EMC8000, a Behringer phantom power supply, a M/F XLR cable, and an XLR to 3.5mm cable to connect the mic to my iMac.  While the hardware appears to work, I am not confident that I will successfully figure out RoomEQWizard or any other application.  RoomEQWizard plays, and the mic picks up the output, and the software makes a frequency response line (with a big bump at 40-something hz and a big dip at 200-something hz), but the -18dB headroom, filters, calibration, etc. is beyond me.   

More reading for me.      Also, I need to remember to wear ear plugs next time. 

[TomS]

.... Also, I need to remember to wear ear plugs next time. 

Just so you know, the level doesn't really need to be that high for the measurement unless you have a ton of ambient noise in your environment.  The mic is pretty sensitive.