Simple Filter insert without phase issues?

I am looking for a high pass/lowcut filter to do a sweep of my kick and bass on ends of phrases but when the filter is set to its minimum, it introduces a phase shift on the low frequencies. Only when I disable the insert, does the phase issue disappear.

Only Fabfilter Pro-Q3 set on “linear phase - High” can do this but it introduces HUGE amounts of latency…

Please help!

It is in the nature of “minimum phase EQs” to introduce phase issues. Especially in the lower frequencies. As you’ve already discovered, the solution is to use a “linear phase eq”. These however have their own tradeoff in terms of “pre ringing”.

There are plenty of articles explaining the differences in more detail.

In EDM one would simply exagerate the sweep so much that phasing becomes part of the sound, e.g. with a resonant filter plugin like MorphFilter. I assume this is not an option for you?

Frequency2 introduces 21.3ms latency on 48kHz. Maybe that could be an alternative to Pro-Q3?

I’ve found that Frequence2 linear phase has a lower latency than Pro-Q3. The problem I have is that when the filter is down at it’s minimum when I don’t use it, the kick is phase shifted and only when I disable it, does the kick sound the way it’s suppose to…

This is supposed to happen. A low cut at 10Hz, which would be the minimum you have it at, will shift the phase, as will any EQ change on a minimum phase EQ.

On a good note, you’ve discovered a nice trick to “fix” phase issues in some instances… a low cut on one signal at the right frequency will adjust the phase enough to align it with the other signal.

This is expected.
I didn’t do that for quite some time but I know that I dealt with it by using 3rd party filter plugin where the lowest frequency, phase shift is not noticeable. No chance to remember which one it was though.

The linear Phase will introduce pre-ringing (smear) to Kick. Phase ‘issue’ of a standard EQ is much more pleasant to the ear than pre-ringing.

My quick solution is to bounce to the audio part with filter automation. Faster than adding on/off automation especially since you have to pay attention to potential clicks, so rather a few ms before the next kick than right on it.

Hi, totally get you here as myself searching for same solution when HP filter is in lowest state (20hz) it being bypassed and as soon it get to 21hz it got engaged(without clicks and pops) and starts working and when it’s back to 20hz it being bypassed and restores original phase. Unfortunately this isn’t quite easy to achieve since there are not anything intuitive on the market that will turn off filter when it’s “done” and I would skip Lin phase cause it’s introducing lot of pre ringing (especially above 12db per octave) and latency is second main issue. As technical paranoid myself for low end and theirs phase coherence I assume you are mostly in electronic music genres like myself. I found several options:

  1. Using xfer djm filter which I suppose it basically bypass filter when it’s on middle (i tried it long time ago but cannot remember correctly)
  2. Using pro q but manually bypassing it when it’s not “working” -be careful this can introduced some pops when automating bypass so you have to find sweet spot where it turns on/off, also you may adjust timing of automation since pro q has smooth interpolation (in practice it’s not that fast and you have sense it’s lagging especially on fast kinda ramp automations)
  3. The Best solution i found is in Melda plugins where in their modular MXXX i program unit which will do exactly i described above (turn off HP filter when it’s on 20hz, as well LP filter when it’s on 20khz) and the best thing is that you can go pretty detailed and technical, it has smooth bypass option where I achieved basically no pops/clicks in practice and the best thing automations are fast without smoothing (apart you can set that as well) so for example when you automate volume and it goes straight from 100 to 0(ramp) it doesn’t slips any fade out signal but the “mute” effect is instant. You can try Mbandpass(free) which i used in MXXX.

More on topic here: Filter automation is too low rate


Thank for the info. I gave Mbandpass a try but unfortunately, it’s the worst of the lot.
In the end Fabfilter’s Volcano 3 did the trick because the lowest it can go is 4Hz and makes almost no difference to the wave. I put an oscilloscope after to check and audibly I can’t hear a difference when disabling the plugin. The response is quick enough as well.

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