I've had no changes to my system since my last set of "reference" measurements. But after a rather nasty electrical incident I decided to run new sweeps and compare them to my references. I set up my UMIK-1 in its standard position (it's always in the same place, +/- 1/4-1/2"), and set the Calibration level at the same amplitude (75 dB(C), +/- a tenth or so). The SPL sweeps looked about the same. I did Trace Arithmetic subtraction of one from the other and got pretty much nothing. But when I looked at the Distortion graphs I was surprised (and now worried). Here's what it looked like before the incident:
and here's what it looks like after:
To me this looks like something happened, but I'm not an expert in interpreting distortion data. I don't know if slight mic position differences could cause this, or anything else for that matter other than some potential damage. Audibly, the music sounds the same as always... I think. My room is well treated acoustically and there was no outside noise or other intrusions when I did any of these sweeps.
and here's what it looks like after:
To me this looks like something happened, but I'm not an expert in interpreting distortion data. I don't know if slight mic position differences could cause this, or anything else for that matter other than some potential damage. Audibly, the music sounds the same as always... I think. My room is well treated acoustically and there was no outside noise or other intrusions when I did any of these sweeps.
Can you help me understand what could cause this degree of variation in the noise floor?
