My take on the video is that he did not have an error. He used simulation and then actual measurements showed that the results do appear to be excellent when measured, presumably on axis. However, the nature of an omni-directional mic is that it cannot differentiate between direct and indirect sound as we do. Matthew Poe's used listening window response as better indication of the perceived sound. I am not sure what software was used to measure the listening window.
It may be that a vendor of room EQ pursues flat measurements because it sells the product. None have after measurements, only predictive measurements.
Looking at the wave lengths above Schroeder and the size of the multi-measurements, I find the impulse response hard to fathom.
My take away is for bass, only multiple subs are effective for room mode issues. REQ can be used to tame room modes and as broadband tone-controls, but applied to correction is may cause problems not reflected by the measurements. Bias is a huge factor, since most believe the predictive charts and want to believe there is an improvement other than bass.
Folks should pay close attention to that video because the list of problems that could not be corrected by room EQ or PEQ is larger than those that it can correct
I did not find an improvement from Dirac on the XMC-1, I have just received the Dirac 3.0 kit for the RMC-1 and will test it again. The first try will be to set the curtain as close to 20 Hz as possible and compare it to Reference Stereo mode. I'd like to identify the cost, if any, as a baseline.
- Rich
I never even implied he had any error at all. I was simply saying I tried putting the mic all over the places (yes still within a bubble) and it did not reveal what he did but then as you said he used a simulator that he consider accurate and I simply did it by moving the mic. The averaging part seems to be the same, done with REW. He also used an expensive mic but I don't think that was the reason why he found the issues that I did not. I think the reasons are mainly due to the different measurement protocol and the software/simulator involved. As to whether the listening window he used is a better indication of the perceived sound I don't know, but he obviously know much better than I in choosing/defining the listening window so chance is good that his listening window is better than mine. For one thing, I did not use a protractor to measure the off axis angles, I just eyeballed them, for distances moved in the X-Y-Z directions, I did actually measure each, using the mmp as reference.
Regardless of how much we trust Mathew's technique and methodology (and I do in general..), I would like to see one or two more similar studies/experiments done by other knowledgeable individuals. I wonder if Amir can do that too, I bet he can because he likely has the software and equipment already.