Temporary acoustic treatment

[Soundman2020]

Well that's a nice improvement! You are hitting the 33 Hz. modal problem nicely now. It's down from the original 1800 seconds to about 650 ms, the overall response is smoother, and the total decay time is now down to around 230ms, form the original 1100ms, and is fairly constant across the spectrum, even in 1/3 octave measurements.

Those times are great, since theoretically for that room IEC specs say it should be 246 ms, and AES specs say it should be 208ms, in both cases rising to 550 ms (IEC) or 500 ms( AES) in the low end. so you are pretty good on that.

It's clearly much more accurate now, and much tighter in the bass. Still room for improvement, though.

There's still some strange things in there: Are you sure you did the latest set of tests at exactly the same settings as last time, and with the mic in the exact same position? The levels seem to have changed: some of that is due to the adjustment of the roll-off, but there seems to be more difference than just that.

Also, the levels are not even the same between the left and right speakers. Did you check that they are putting out the exact same level on both sides? It should be 83 dB(C) for each speaker individually, when it is on only by itself, measure with your sound level meter, and using the pink noise generated by REW itself. That should give you between 86 and 89 dB for both speakers.

The mic position is critical as well: you must get the mic back to the exact same location in the room for each measurement, which should be the location of where your head will be, and on the room center-line. The location will be different from what it was for the first test, of course, since you corrected the mix position after that, but from now on it has to be accurate for all future readings. Measure the position carefully to the side walls, front wall, and floor, to within a few mm, and always get the mic back to that point.

I'm wondering why there is such a big difference between the left and right readings... Did something change in the room between the Left and Right readings? Such as a piece of furniture was moved, or a person was in the room, or something like that? Or is there something that is asymmetrical about the room itself? Some that is on one side but not the other?

Anyway, it's good to see that the treatment is now working much better, especially since you put the cloud in: More is still needed, but what you have now is streets ahead of what you had originally.

- Stuart -