Reducing quantization "warble"

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antonriehl
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Reducing quantization "warble"

Post by antonriehl » Tue Mar 09, 2021 1:25 pm

I love using my uTune, and it's one of the modules in 3/4 of the patches I make, but sometimes I get this "warble" (I don't know a better word) where the incoming CV seems to be close enough to two different notes, or fluctuates enough, that it trills between two different notes. I'm curious if people have ways to reduce this effect, or if there are other ways to stabilize CV going to the input? I have heard it happen on other systems before, but I feel like I hear it more in my system than in other people's.

Just for some background, I have 1 expander, and am running the current version of the firmware. I will typically take a random source, and run it through an attenuator/verter, usually with an offset of some kind (it has been A*B+C lately), and then into uTune.

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Re: Reducing quantization "warble"

Post by tubbutec » Wed Mar 10, 2021 8:18 am

Hi, I can not tell you of course if your amount of warble is typical or not. It is always introduces by a fluctuating CV. µTune actually uses hysteresis around the quantisation steps to reduce warble but of course there is a limit to this. As soon as the fluctuations are in the range of half a semitone you will hear them.

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Re: Reducing quantization "warble"

Post by BananaPlug » Wed Mar 10, 2021 9:11 am

To allow the settling time you can put a short gate delay ahead of the envelope generator's trigger. This may lead you to other complications depending on how precise your timing must be and whether you can shift it in post-production.
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Re: Reducing quantization "warble"

Post by tubbutec » Wed Mar 10, 2021 11:13 am

Such a trigger delay is built into µTune ! When using triggered or gated quantization it is active and you can adjust its length as well

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Re: Reducing quantization "warble"

Post by antonriehl » Wed Mar 10, 2021 5:46 pm

Thanks, your replies all make sense, and I knew there wouldn't be a "simple" answer to address this. Just thought I'd see if there were any other tricks. It's one of those things that is so strange because sometimes it happens a lot, and other times you don't even notice it. I think it is probably something I can overcome more with practice, and timing gates/clocks.

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Re: Reducing quantization "warble"

Post by tubbutec » Thu Mar 11, 2021 7:52 am

Depending on your CV sources and how stable they react to power supply fluctuations, it might be your power supply.

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antonriehl
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Re: Reducing quantization "warble"

Post by antonriehl » Thu Mar 11, 2021 9:21 am

It seems to happen regardless of what cv source I’m using, but I haven’t done a lot of specific tests to see. It does seem to happen more at higher voltages than at lower ones. But, that is currently purely anecdotal.

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Re: Reducing quantization "warble"

Post by acidbob » Thu Mar 11, 2021 9:24 am

Do you have a scope available?

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antonriehl
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Re: Reducing quantization "warble"

Post by antonriehl » Thu Mar 11, 2021 9:26 am

I do not at the moment. (Although I could use the one in VCV rack… so kinda?)

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Re: Reducing quantization "warble"

Post by Jazzman » Sat Mar 13, 2021 1:39 am

tubbutec wrote:
Wed Mar 10, 2021 8:18 am
Hi, I can not tell you of course if your amount of warble is typical or not. It is always introduces by a fluctuating CV. µTune actually uses As soon as the fluctuations are in the range of half a semitone you will hear them.
can you recommend where I might learn more about using "hysteresis around the quantisation steps to reduce warble"?

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Re: Reducing quantization "warble"

Post by tubbutec » Mon Mar 15, 2021 6:36 am

There is nothing you can change about the hysteresis, it is built into µTune's input algorythm.
But if you do want to know:
It is explained here:
https://electronics.stackexchange.com/q ... hysteresis
Only difference in µTune is, that you have multiple hysteresis bands, one for each possible input voltage. So if you have a scaling of 12notes / V at the input, µTune will use 12 bands / V

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