Question about phase issues from excessive eq
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- KVRist
- Topic Starter
- 110 posts since 25 Sep, 2018
When people say excessive EQ causes phase issues, do they mean issues like every time the midi triggers a bass note or something, it changes phase? Cuz all i have going is eq and compression and now all the sudden every midi that triggers the bassline sound different from eachother.. like i have some detune without retrig on or something.. Is this work of the EQ?
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- KVRian
- 629 posts since 15 Jun, 2017
EQ is based on filtering.
Specific types of filters inherently cause phase changes. Then, phase characteristics of input signal are not equal to phase characteristic of the output signal.
It goes way to far to go into details, but a short intro into filters and phase...:
http://www.dspguide.com/ch19/4.htm
It starts by stating: "There are three types of phase response that a filter can have: zero phase, linear phase, and nonlinear phase."
The important part is that there are filters that do NOT interfere with phase and those that do. And that there are all sorts of variants of filters and phase change characteristics.
This does not mean that one is better then the other, but filters do differ in charateristics....and may cause phase changes.
Specific types of filters inherently cause phase changes. Then, phase characteristics of input signal are not equal to phase characteristic of the output signal.
It goes way to far to go into details, but a short intro into filters and phase...:
http://www.dspguide.com/ch19/4.htm
It starts by stating: "There are three types of phase response that a filter can have: zero phase, linear phase, and nonlinear phase."
The important part is that there are filters that do NOT interfere with phase and those that do. And that there are all sorts of variants of filters and phase change characteristics.
This does not mean that one is better then the other, but filters do differ in charateristics....and may cause phase changes.
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- KVRAF
- 2565 posts since 2 Jul, 2010
For a regular EQ the phase shift is consistent at each frequency, so I doubt this is the problem OP is facing. If it is inconsistent from note to note that is probably related to a free oscillator phase in the synth. Does the problem really only appear when you enable EQ?
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- KVRian
- 629 posts since 15 Jun, 2017
You are right. Actually reading the post (...) it's the retrigerring of notes that cause changes in sound.imrae wrote: ↑Thu Feb 14, 2019 12:13 pm For a regular EQ the phase shift is consistent at each frequency, so I doubt this is the problem OP is facing. If it is inconsistent from note to note that is probably related to a free oscillator phase in the synth. Does the problem really only appear when you enable EQ?
It's probably just phaseshift between overlapping notes. Or free running (non-phase-synced) oscillators in the synth. That causes combfilter effects.
More generalized about delay/combfilter effects:
https://www.youtube.com/watch?v=dQ5DEdO9ELg
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- KVRian
- 629 posts since 15 Jun, 2017
Maybe just provide some audio examples at this stage? Your desciption leaves a lot of possibilties open.Brandon203113 wrote: ↑Wed Feb 13, 2019 3:48 pm When people say excessive EQ causes phase issues, do they mean issues like every time the midi triggers a bass note or something, it changes phase? Cuz all i have going is eq and compression and now all the sudden every midi that triggers the bassline sound different from eachother.. like i have some detune without retrig on or something.. Is this work of the EQ?
If it's phase shift due to overlapping notes / freerunning oscillators, then you'd have the same issue with or without EQ and/or compression. But you state that it's only there when compression and/or EQ are engaged.
Since you also coin the term "excessive", it could be just as well be your compressor that destroys the signal. A bass note can easily be destroyed by high compression ratios and fast attack times. Depending on the attack and release time and the time between notes (maybe also in a parallel "New York" configuration) you can create all sorts of strange behaviour. You might even be using a dynamic EQ that could change it's behaviour depending on the input signal.
Anyway....a better description of what you're doing and what you're using and some audio examples of the sequence with and without compression and/or EQ sure would help.
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- KVRist
- Topic Starter
- 110 posts since 25 Sep, 2018
the synth is completely phase synced, It always starts at the beginning of the wavetable on both oscillators every single time.. And i don't know if you're referring to phase when only different notes are being played alongside the sound or if the notes playing alongside the sound can be the same exact note.. The only other sound being played at the same time is the sub bass.. Which is the same note. but what i realized is that if i turn the sub off, i don't hear the phase when the sound is solo.. It must be that they are conflicting??? even though they are pretty damn well eq'd away from eachother???
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- KVRist
- Topic Starter
- 110 posts since 25 Sep, 2018
I don't understand because it couldn't have been the eqs of the sub and mid bass clashing either though......cuz i bounced to audio and repitched it around to play the bassline and now theres no phase... i seriously have no idea, i shouldve turned all the eqs off and multiband off to see if the phase dissappeared but i bounced already. if the problem occurs again and i have a chance to find out, ill post here and let everybody know what it was..
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- KVRist
- Topic Starter
- 110 posts since 25 Sep, 2018
It had to have been some weird behavior of either the multiband or eq, there were no dynamic eq's used, but yeah. I know for damn sure it wasn't a setting i had on in the synth or something, i know my synthesizers all too well. It was something in the post... or clashing from the sub, but its strange cuz i bounce to audio then they aren't clashing anymore soooo... im sticking with something weird from eq/comp in the post...Kwurqx wrote: ↑Fri Feb 15, 2019 8:56 amMaybe just provide some audio examples at this stage? Your desciption leaves a lot of possibilties open.Brandon203113 wrote: ↑Wed Feb 13, 2019 3:48 pm When people say excessive EQ causes phase issues, do they mean issues like every time the midi triggers a bass note or something, it changes phase? Cuz all i have going is eq and compression and now all the sudden every midi that triggers the bassline sound different from eachother.. like i have some detune without retrig on or something.. Is this work of the EQ?
If it's phase shift due to overlapping notes / freerunning oscillators, then you'd have the same issue with or without EQ and/or compression. But you state that it's only there when compression and/or EQ are engaged.
Since you also coin the term "excessive", it could be just as well be your compressor that destroys the signal. A bass note can easily be destroyed by high compression ratios and fast attack times. Depending on the attack and release time and the time between notes (maybe also in a parallel "New York" configuration) you can create all sorts of strange behaviour. You might even be using a dynamic EQ that could change it's behaviour depending on the input signal.
Anyway....a better description of what you're doing and what you're using and some audio examples of the sequence with and without compression and/or EQ sure would help.
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- KVRist
- Topic Starter
- 110 posts since 25 Sep, 2018
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- KVRist
- Topic Starter
- 110 posts since 25 Sep, 2018
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- KVRAF
- 4065 posts since 2 Jul, 2005
It sounds like the sub and main bass were constructively and destructively interfering with each other from your description. Should be easy enough to avoid.
Don't F**K with Mr. Zero.
