Low phase growth tune

[NBPK402]

Can REW do a low phase growth tune, in the autotune mode?

 

[John Mulcahy]

The target match of the EQ window looks at response magnitude, not phase.

 

[NBPK402]

The target match of the EQ window looks at response magnitude, not phase.

Any plans in the future of being able to do a low phase tune?

 

[John Mulcahy]

Never heard of it, so no.

 

[Chris A]

Ron,

I think that the last time I tried using Dirac (the full version) on my Emotiva AVP, it appeared to be doing some sort of FIR filtering flattening of the midbass response (but not a lot). If it can do that, my guess is that it will try to do phase flattening at higher frequencies. You can think of that as "automatic", but there are some real downsides to "room correction" firmware, notably in the midbass region where your room starts to become the limiting dimension in reproduction of acoustic waves (i.e., the so-called Schroeder frequency of your listening room). These automatic packages always seem to screw up that portion of the spectrum, resulting in a thin sound overall.

There are other solutions available to use FIR filters to flatten phase, most notably RePhase as found mostly on diyAudio, etc., but there are other tools available. The problem is that you need some sort of DSP app or FIR-capable crossover box to flatten phase. And it's definitely not "automatic".

The processes that I use are all focused on eliminating all the all-pass phase growth through the crossover interference bands, but I live with the minimum phase response of the individual drivers in each way of the loudspeakers themselves. This is a very low-cost way (from a computing standpoint) that seems to give a 99% solution (i.e., within ±55 degrees of total phase swing for our MEHs) that seems to be below the threshold of audibility without having to resort to FIR filtering, with all its computing requirements and insertion delays.

YMMV.

Chris