Originally Posted by PlasmaPZ80U
So I measured my impulse response of all 5 speakers and sub, Room Correction off, bass management off, speakers 15-20,000Hz and LFE channel 15-300Hz with acoustic timing reference set to right surround speaker as it is closest to MLP. I left the speaker and sub distances at where YPAO set them, which is:
SW 6.4ft (was 8.4ft before sw dist tweak but set at 6.4ft during these measures)
Issue is FL, FR, CC all are before 0ms and SL and SR are at 0ms. Why is that considering YPAO set these distances/delays and they are very close/matching tape measured distances?
Let's put this in perspective. The alignment difference between the FL and FR speakers is .22ft, or .2ms. That is insignificant. The alignment difference between the FL and the SR (the timing reference),is .93ft, or .83ms, also quite small. Keep in mind that the MCACC and the REW mic are different mics, and being able to place the REW mic in exactly the same spot at the MCACC mic would be extremely difficult
. I think the differences you are seeing are due to mic placement variations, and I would not adjust the MCACC settings based on the REW measurements.
I was also very concerned with comparing REW impulse response measurements with the results from automated room correction. As a Dirac Live user, I am fortunate to be able to use the UMIK-1 mic for both the REW measurements and the Dirac calibration. I conducted this experiment:
1. Place the UMIK-1 in the MLP.
2. Run a one-position Dirac calibration and save the results to an 88A pre-set.
3. Using the 88A Utility program, observe the Dirac delays.
4. Without moving the mic, run the REW measurements for each channel.
5. Using the REW Impulse Response Overlay, observe speaker alignment with the Dirac delays.
The results are shown below. Without moving the mic, the alignment looks perfect, IMO. IOW, room correction does a fine job aligning speakers.