Bob's Corner Trap Tests 2004/06/27

Inspired by Studiotips

Apparatus

Microphone: Beherenger ECM8000

Microphone cable: 20' radioshack microphone cable

PreAmp: Beherenger Euroback UB802

Speakers: Cambridge Soundworks MegaWorks 510D, one satelite connected, one subwoofer connected

Amplifier: Yamaha RXV2400, CD in, DSP set to StraightThrough, crossover at 100 Hz.

ETF5, running against Creative SoundBlaster USB MP3 Model SB0270, on Pentium IV 3.2ghz

Roxul RHF-80 rockwool, 2'x4'x2" batts

Owens Corning R-31 Attic Fiberglass Pink fluffy in bag

Room is L shaped, with the main section about 223" x 264" x 99" (at the microphone) Room Measurements Basement Pictures

Method

The speakers were placed 25" from one wall and 76" from another wall, and microphone was placed 25" from one wall and 76" from another wall, each pointed at the corner. The microphone is 24" off the ground.
In all tests the microphone and speakers were untouched.
The Close test was quieter than the rest. All the others used the same volume and the same UB802 gain settings without change.
UB802 had the microphone linein 1 gain at 0 (full left), EQ high/mid/low at 0 (midway), FX at 0 (midway), pan LEFT, level 0 (midway), phantom on, main mix gain 0 (midway), tape out left to soundblaster.
Each sample was placed in the target corner, photographed, and three tests were made using ETF5. In each sequence of three tests nothing was changed: not the speaker volume and not the sample.
Whenever ETF5 reported that the level was too high or too low, that test was not recorded. Only tests that showed "level ok" were used.
Test 1 through Test 3 are all conducted from the same mic position. I.e., they are three (3) measurements that should - for all intents and purposes - be identical
There is an audible hum, but it's quieter than the noise ETF5 makes for its signal