How to deal with phasing at mixing a filtered signal(has phase shift) with dry signal

Hello ,
I have a phasing issue due to the phase shifting in filtered wet signal when i try to mix it with dry signal. I try to see the behavior on Plugin Doctor. The amount of the phase shifting is changing according to the cutt-off frequency of the filters.So it is not a fixed number. When i try to mix a filtered signal with it’s dry signal, it creates a phasing.
Do you have any suggestion ? How do you fix this issue on your mixing stage ?
Thanks in advance :pray:

You can do something like this:

  • Compute the amount of delay introduced by filtering and other processing. This will be dependent on the exact processing you’re doing.
  • Delay the dry signal by this same amount. juce::dsp::DelayLine may be useful for this step.
  • You should also report the total latency of the plugin to the host using AudioProcessor::setLatencySamples. This ensures that the host can compensate for the latency and avoid phasing if the user chooses to mix outside of your plugin.
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it would make sense to say if you’ve implemented a FIR or IIR filter first.

about the musical value of phase shifts:
the fact that the term “phase issue” is thrown around on the internet so much makes it a nice buzzword to sell your FIR-based filter plugins at a higher price even though they are computationally more expensive and cause more latency, but phase shifts are not really an issue when mixing music. sure if you’re trying to layer 2 bassdrums and eq the lowend of one of them with a steep highpass filter you’ll completely mess up the entire lowend if it worked before. but on the other hand if it had worked before you wouldn’t have started to eq it hard in the first place. so these phase shifts can also be beneficial just as much as they can be bad. linear phase filters are only a solution if you’re ok with pre-ringing artefacts and a higher cpu load

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Thank you. Implementing the delay is easy but i have not calculated the latency of a buffer before. How can i do that? What would you suggest ?

Thank you for your answer. You are right. There is a musical side to it.

Yes, this is what I did. After adding a few filters the phasing becomes audible. That is why I want to reduce it a bit.

no i mean, did you choose fir OR iir?


iir have a very short latency and also an unpredictable one, so you can’t really compensate for it. on top of that the phase response is different across the whole spectrum. use bertom’s eq curve analyzer on your plugin to see that in action. you’re probably better off ignoring this issue for now and maybe later consider adding the feature to let the user switch the filters to FIR (linear phase) optionally

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Sorry, I just noticed your reply. Thank you for the suggestion. I will check that analyzer. I did not know that one. Thank you for your answer :pray: