Hi
Which settings do you use to deal with room modes?
Here they are :
Where is it effective: listening position only or wider area?
It is effective nearly everywhere. Even in other rooms, it is much better with correction than without. We can hear music coming from the next room, instead of a heard of elephants thumping.
It is because the listening position stands at the maximum of the strongest mode.
According to the room simulation, the 54 Hz peak is the second order of the front / back axial mode :
The level of a 54 Hz frequency across the room is given by the thick blue curves. At the listening position, the measurement says that it is 18 dB too loud. Therefore the right level should be the one given by the two dark green lines.
The bright green areas represent the regions where the -18 dB correction have an optimal effect.
The light green areas represent the regions where the -18 dB correction is better than nothing (better having a notch than a peak).
The orange areas represent the regions where the -18 dB correction is bad (it was ok, but the correction creates a notch).
According to the room simulation, the 69 Hz peak is the first order of the floor / ceiling axial mode :
The vertical light green lines represent the actual level at the listener's position.
The vertical dark green lines represent an amplitude 10 dB inferior, that is the ideal amplitude for this frequency.
The bad zone after EQ is the region where the dark blue curves fall inside the dark green lines.
Do you use different settings for each channel?
Not for room modes, but for SBIR, yes.
If we compare the measured frequency response of both speakers playing the test signal together, we can see that the result is not the same as the sum of the frequency responses of the left and right speakers alone :
The peaks are higher at 160, 200 and 330 Hz when both speaker are actually playing together because of constructive interference, which adds 6 dB to the initial level, while at higher frequencies, the signals coming from the left and right speakers are incoherently averaged, which gives +3 dB only.
But at 62 and 100 Hz, when the speakers play together, the sound is actually quieter than when they play separately ! (destructive interference).
I prefer equalizing both speaker at the same time because more often than not, music is played in both channels at the same time. Especially in low frequencies, that are 90% mono. Thus the measurement made with both speakers is closer to the actual level.
But since I was never satisfied with the correction of the peak around 200 Hz, and since they are actually two separate peaks for the left and right speakers, I decided to try separate left and right corrections. I don't know for sure it the result is better, though.
Are the corrections different depending on the type of music and loudness?
No. I'm happy with my settings with any kind of music at any level.
