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My apologies if this has been thrashed out elsewhere.
I have seen various opinions on mic measurement angle, and most tend to lean toward 90 degrees. I thought that might also help with the fact that there is obviously a body at the main listening position when the system is actually playing music, so I ran a quick test. First, some background...
The listening room is not the best when it comes to dimensions, 21 feet long, 17 wide, and 7 feet high, in a basement where there's a post almost directly in the center. The only way to get a reasonable symmetric arrangement is to place the sofa up against the post. The speakers are 76" center-to-center and 91" from the center of the sofa. Due to enormous slap echo, I put in a lot of 2" thick rigid fiberglass absorbers (homemade...LOL no way could I afford to have bought all of it otherwise!) All things considered, I get far less difference left vs right than I see in other room measurements.
Here's the mic placed without any pillows...
and here it is with some pillows placed to roughly simulate the presence of a body. I didn't touch the mic at all, and while it looks as if it's not at 90 degrees, that's not the case.
I ran multiple sweeps in REW (matching was dead on up to 15 kHz) and applied psychoacoustic filtering. Here are the resulting traces:
Ok, yeah, I know this is a single point...but look at the massive differences in SPL from 600 Hz and 1200 Hz between the two.
I measured this prior to implementing the sub crossover on the DDRC-24 and running Dirac Live. My plan was to run Dirac for a tightly focused central listening position. We're empty nesters, and I am the only one who uses the system. My understanding is that regardless of which correction algorithm is used, they tend to give more weight to the central measurement.
If the response in that critical frequency region can be shifted by as much as 6-7 dB by the presence of those pillows, does measuring response over a reflective leather sofa without any bodies present, even using the mic at 90 degrees, create anomalies that present significant problems in developing a proper correction?
I have seen various opinions on mic measurement angle, and most tend to lean toward 90 degrees. I thought that might also help with the fact that there is obviously a body at the main listening position when the system is actually playing music, so I ran a quick test. First, some background...
The listening room is not the best when it comes to dimensions, 21 feet long, 17 wide, and 7 feet high, in a basement where there's a post almost directly in the center. The only way to get a reasonable symmetric arrangement is to place the sofa up against the post. The speakers are 76" center-to-center and 91" from the center of the sofa. Due to enormous slap echo, I put in a lot of 2" thick rigid fiberglass absorbers (homemade...LOL no way could I afford to have bought all of it otherwise!) All things considered, I get far less difference left vs right than I see in other room measurements.
Here's the mic placed without any pillows...
and here it is with some pillows placed to roughly simulate the presence of a body. I didn't touch the mic at all, and while it looks as if it's not at 90 degrees, that's not the case.
I ran multiple sweeps in REW (matching was dead on up to 15 kHz) and applied psychoacoustic filtering. Here are the resulting traces:
Ok, yeah, I know this is a single point...but look at the massive differences in SPL from 600 Hz and 1200 Hz between the two.
I measured this prior to implementing the sub crossover on the DDRC-24 and running Dirac Live. My plan was to run Dirac for a tightly focused central listening position. We're empty nesters, and I am the only one who uses the system. My understanding is that regardless of which correction algorithm is used, they tend to give more weight to the central measurement.
If the response in that critical frequency region can be shifted by as much as 6-7 dB by the presence of those pillows, does measuring response over a reflective leather sofa without any bodies present, even using the mic at 90 degrees, create anomalies that present significant problems in developing a proper correction?