Major CR nulls.

contrastrecording · Post by **contrastrecording** » Mon Jun 12, 2006 2:50 am

Mic was 47.5" from the front wall, which puts it just slightly inside the 35" triangle of the monitors. And yes, the distance was to the cone itself, not to the rear of the box.

David French · Post by **David French** » Mon Jun 12, 2006 5:31 am

Yeah, I did all this math, and none of the numbers worked out.

Hard to say what's wrong without being there.

contrastrecording · Post by **contrastrecording** » Mon Jun 12, 2006 4:04 pm

OK, well I spent about 4 hours running tests today. Basically, I found that height had a lot less to do with the problem than I thought. The biggest changes happened when I moved the monitors either closer together or further apart. Basically, closer together was flatter, but I can't really have them in any closer than 35" or so, and the difference between that and 20" or even narrower was very small (I tried 5 inch increments from center out to 54" apart, the widest I can go). The very best (excluding those I cannot implement, like everything 35" off the ground) position I found was with the microphone at 47.5" from the front wall, and the monitors in a 35" triangle. I did a LOT of tests (changing height of monitors and microphone, moving the mic around the room, etc.). I concluded that height really had little effect on the overall response, compared to the other variables (I tried anywhere from 35" up to 61"). So, I just went with the monitor stands I've been using (putting the midpoint of the monitors at 49"). FWIW, higher was worse.

At this point, I decided to see what effect the side walls were having. Seemed like the logical choice, since moving the monitors in relation to them changed the response considerably. So, I took out the middle section of the slat resonators. Bingo. Problems got worse, nulls were deeper, wider, etc. I thought, well maybe the slat resonators aren't really doing their job. I replaced them with 6" of 703 placed at an angle across the corner. The difference between null and peak was reduced about 3dB more than with the resonator, BUT the null was quite a bit wider. And it was still over 10dB deep, so I'm not satisfied with that either. Any ideas?