Click / pop / crackle sound on pitch changes after key reset

[mixxxbot]

Reported by: ubuntu-linux-user
Date: 2021-06-27T10:35:08Z
Status: Confirmed
Importance: High
Launchpad Issue: lp1933756
Attachments: [Demo sound to reproduce the problem (sine wave at 440Hz)](https://bugs.launchpad.net/bugs/1933756/+attachment/5507433/+files/Demo sound to reproduce the problem (sine wave at 440Hz))

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Problem:
A click / pop / crackle sound is introduced whenever the key crosses the original key of the track on non-zero pitch.

Steps to reproduce the problem:

1. Load the attached sample (a constant 440Hz sinus wave)
2. Change the pitch to position p = +0.5% (any non-zero value will do)
3. Reset the key (e.g. Right click on the key symbol on LateNight skin)
4. Play the track and move the pitch slider around p.

Effect: Whenever the slider crosses p, a click / pop / crackle sound is introduced.

This behavior is particularly problematic in combination with vinyl control: an analog record introduces a continuous pitch variance of a few 0.0x% (at least on my machine). When the key is reset, this leads to heavy click noise, because the pitch continuously goes below and above p.

The problem does not occur when pitch is set to zero.

The problem is independent of the Pitch-Bend-Engine, it occurs with Soundtouch as well as with Rubberband. It occurs on a Windows notebook and a Linux desktop machine with different hardware, so I guess it is not a driver issue.

Environment:

• 2.3-beta-3981-g54652f2248 / Windows x64
• 2.3-beta-4146-g827c82dde / Linux x86_64 (Ubuntu)

[mixxxbot]

Commented by: ubuntu-linux-user
Date: 2021-06-27T10:35:08Z
Attachments: [Demo sound to reproduce the problem (sine wave at 440Hz)](https://bugs.launchpad.net/mixxx/+bug/1933756/+attachment/5507433/+files/Demo sound to reproduce the problem (sine wave at 440Hz))

[mixxxbot]

Commented by: daschuer
Date: 2021-06-28T07:58:24Z

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A fix is here:
#4030

[mixxxbot]

Commented by: daschuer
Date: 2021-09-30T06:29:24Z

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Unfortunately the fix introduces the risk for an underflow due to the double amount of CPU which is worse because it affects all decks.

I don't see a chance to fix this in a dot release. I am afraid this issue needs to be solved within soundtouch and rubberband.

[mixxxbot]

Commented by: ubuntu-linux-user
Date: 2021-12-07T08:42:07Z

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According to #4030 (comment) this issue should be discussed upstream at

• https://sourceforge.net/p/soundtouch/discussion/
• https://todo.sr.ht/~breakfastquay/rubberband

[git-developer]

Demo sound to reproduce the problem (sine wave at 440Hz)