Here is the latest butchering of the frequency response via calibration with the app.
This is the subwoofer’s “corrected” response. For whatever reason, the app has decided that the subwoofers -3dB point is 41hz, and equalized the response to be ruler flat above this point.
How it got this, I’m not exactly sure, but my running theory is that it decided the highest level of the peak at 50hz was the point it was going to reference the rest of the measurements by, and went by the point -3dB down from the max level at 50hz, which happened to be 41hz, seeing as how room modes generally cause a boost that rolls off 6dB/octave either side.
It’s obvious that it quit applying corrections below 41 hz. Since Audyssey not only corrects frequency response errors, but temporal errors as well, you will usually see the low frequency measurements where correction is applied will have an almost perfectly flat phase after correction. Here it does a full flip at 47hz, where the room has little effect on LF. The measurements were taken near the back wall, so everything from 50hz up to the Schroeder frequency is about 180 degrees out of phase from everything below due to reflection from the rear wall.
Note that it’s only the app that does this. The avr does a fairly decent job most of the time.
This one was done with the AVR instead of the app, it’s not perfect, but this calibration was done in a small square room, so I can’t complain. This is the combined response of the main speakers and the sub. The subwoofer by itself measures flat from 30hz to 100hz, with a slight roll off about 5dB from 30hz to 23hz, which seems to sort itself out when combined with either a 40hz or 60hz xover to the LCR.
I’d be interested to see how the app works for others, I know
@Pogre was having issues with it, but I’m sure if others measured the before and after results they’d be similarly out of whack. I have no idea what’s different about the apps correction algorithm vs the avr, but it’s certainly not even in the ballpark of correct.
