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[sircuit]

I'm in a mastering project right now and I noticed that the low pass for the side / diff ("bass mono maker") within SlickEqM introduce some unpleasant phase shifts.

So I'm looking for linear phase eq... Affordable one for Windows is preferred. Main task will be to make from a certain crossover point frequencies mono. A dedicated plugin would be also fine.

First of all - do you really need a low cut filter? Many times shelving will do just fine. Using low cut of the low end with linear phase is sonic suicide.

[ramseysounds]

https://a1audio.alexhilton.net/a1stereocontrol

[bmanic]

@Autobot

You can make any EQ and Filter linear phase. This is what you do:

1) Apply your filter, render the results to the audio. If you are going for 24dB/octave end result, select 12dB/octave instead (because see point '3' below)
2) Now reverse your audio file, so that it plays backwards
3) Apply the filter again.. 12dB/octave (12dB + 12dB at exact same frequency and Q = 24dB/octave) then render
4) Reverse the audio again so that it plays normally
5) Done. You have now applied linear phase EQ or Filter to your file. No need to pay any money for it.

Well Sir, that´s a very clever trick!

I never thought of this before but halfing the filter and applying the phase shift from 2 opposite ways is a very clever and logical way!!

I didn´t try it but I trust you and for me it makes perfectly sense...
At the very end it should be even better as a linear filter as it wouldn´t cause any preringing , would it?

Pre-ringing is just ordinary filter ringing.. so if the filter is prone to a lot of ringing then you of course get both pre-ringing (the reversed file) and post-ringing. The phase however takes out one another meaning of course the filtering becomes linear phase.

The main reason I suggested this method is because it sounded like OP had a special case where you only have to do it once and then perhaps never again use a linear phase EQ/filter again. Thus using this method one could use any of your favorite filters instead of spending extra money (though I'm sure there must be at least a few good free linear phase filters around).

[v1o]

@Autobot

You can make any EQ and Filter linear phase. This is what you do:

1) Apply your filter, render the results to the audio. If you are going for 24dB/octave end result, select 12dB/octave instead (because see point '3' below)
2) Now reverse your audio file, so that it plays backwards
3) Apply the filter again.. 12dB/octave (12dB + 12dB at exact same frequency and Q = 24dB/octave) then render
4) Reverse the audio again so that it plays normally
5) Done. You have now applied linear phase EQ or Filter to your file. No need to pay any money for it.

Well Sir, that´s a very clever trick!

I never thought of this before but halfing the filter and applying the phase shift from 2 opposite ways is a very clever and logical way!!

I didn´t try it but I trust you and for me it makes perfectly sense...
At the very end it should be even better as a linear filter as it wouldn´t cause any preringing , would it?

Pre-ringing is just ordinary filter ringing.. so if the filter is prone to a lot of ringing then you of course get both pre-ringing (the reversed file) and post-ringing. The phase however takes out one another meaning of course the filtering becomes linear phase.

The main reason I suggested this method is because it sounded like OP had a special case where you only have to do it once and then perhaps never again use a linear phase EQ/filter again. Thus using this method one could use any of your favorite filters instead of spending extra money (though I'm sure there must be at least a few good free linear phase filters around).

Are you familiar with REW? Could this method be used for linear phase room and speaker EQ corrections.

[Ploki]

No, because you cant reverse your room.

Also linear phase on speakers is at least 40-100ms of delay and imo sounds like garbage

[rafa1981]

BTW, if you are a Reaper Linux/Windows user I added a linear phase crossover to mixmaxtrix 1.2.0 (VST3). The crossover can be set as 12/24/48 dB/oct with up to 4 bands.

if I find no bug I will be releasing pretty soon.

EDIT: already released.

[aMUSEd]

This one is amazing value for money - very powerful and very underrated (as is IIEQPro but that one is parametric)

https://ddmf.eu/lp10-linear-phase-equalizer-plugin/

[midi_transmission]

I'm in a mastering project right now and I noticed that the low pass for the side / diff ("bass mono maker") within SlickEqM introduce some unpleasant phase shifts.

So I'm looking for linear phase eq... Affordable one for Windows is preferred. Main task will be to make from a certain crossover point frequencies mono. A dedicated plugin would be also fine.

Could you explain what unpleasant happens due to phase shift of the low cut? Genuine interest. I'd like to recreate the problem

[Ploki]

agree, i find
- pointless monoizing for no reason
- linear phase preringing

much more unpleasant than phase shit

[MogwaiBoy]

Yeah.... reducing width on the bass channel, at the source, means no need for bass mono-izing further downstream.

[plexuss]

Sometimes I dont mind bass "monoizing" on the master. I find it depends on the source. If it sounds bad I dont use it... Like every other audio thing....

[mystran]

I'm in a mastering project right now and I noticed that the low pass for the side / diff ("bass mono maker") within SlickEqM introduce some unpleasant phase shifts.

So I'm looking for linear phase eq... Affordable one for Windows is preferred. Main task will be to make from a certain crossover point frequencies mono. A dedicated plugin would be also fine.

Could you explain what unpleasant happens due to phase shift of the low cut? Genuine interest. I'd like to recreate the problem

I don't know about SlickEqM in particular, but in general if you apply ordinary minimum-phase equalization to only the side-channel, this will result in different phase-shift to the mid- and side-channels, which can result in some phasing and/or wonky stereo image in the transition band (where the phase actually varies the most) when you convert back to LR. Whether or not it's a problem, depends on what sort of sounds you happen to have in that transition band, but where as the ear mostly doesn't care about phase at high frequencies, the phase-shift (or equivalently time-difference) is used by our brain for localization below 1kHz (or so), so this is very much a low-frequency specific issue.

One can avoid this by using linear-phase filtering, but one can also avoid it by using a phase-coherent cross-over (eg. Linkwitz-Riley) to split the signal to two bands, such that you can then just adjust the gain of one of the side-bands. The main downside of the linear-phase approach is the preringing (which for a fixed steepness will get longer the lower you go in frequency). The main downside of the Linkwitz-Riley approach is that for low frequencies the required phase-shift for such a cross-over will result in enough (frequency dependent) time-delay that it will give the sound a slightly different character (for better or worse).