Room EQ, do's and dont's

[MRC01]

Yes. If your EQ is minimum phase and the speaker response curve you're correcting is also minimum phase, then the EQ can actually improve both the phase and amplitude response. Even then, a boost may still also increase distortion. But the speaker reasponse curves you're correcting aren't always minimum phase, so the EQ may also worsen phase response and distortion as it improves amplitude response.

Generally speaking, EQ cuts are safer than boosts when it comes to distortion and transparency. Also use the most gentle slopes you can (numerically smallest Q), unless you know both the flaw and the correction are minimum phase.

 

[daftcombo]

Yes. If your EQ is minimum phase and the speaker response curve you're correcting is also minimum phase, then the EQ can actually improve both the phase and amplitude response. Even then, a boost may still also increase distortion. But the speaker reasponse curves you're correcting aren't always minimum phase, so the EQ may also worsen phase response and distortion as it improves amplitude response.

Generally speaking, EQ cuts are safer than boosts when it comes to distortion and transparency. Also use the most gentle slopes you can (numerically smallest Q), unless you know both the flaw and the correction are minimum phase.

I EQ and correct the phase by convolution, with an impulsion generated in RePhase.
It might limit distortion, compared to an analog EQ I think?

 

[Music1969]

Hi @amirm and all,

My understanding is it is generally recommended to limit digital room EQ to the schroeder frequency (200/300/whatever Hz).

But I understand software like Acourate apply digital room EQ to both frequency and time domain (separate functions in Acourate).

Should time domain EQ also be limited to schroeder frequency or best to apply to full audio band?

 

[MRC01]

Above Schroeder you certainly can correct FR with EQ. But these FR nonlinearities are not going to be room modes; they'll be caused by other factors. When I EQ above Schroeder, I don't chase every narrow bump or dip, just use broad corrections to get the overall trend line into shape.

 

[daftcombo]

Hi @amirm and all,

My understanding is it is generally recommended to limit digital room EQ to the schroeder frequency (200/300/whatever Hz).

But I understand software like Acourate apply digital room EQ to both frequency and time domain (separate functions in Acourate).

Should time domain EQ also be limited to schroeder frequency or best to apply to full audio band?

There are two things about your room you could want to "correct" with an equalizer: room modes and reflections.
The first will change the bass response, the second the treble.
IME, the second is easier to correct. A high shelf filter starting at 2 000 Hz could help taming too much brightness in some situations.