pop when enabling Bessel8 ISO in effect unit

[ronso0]

Bug Description

• mix mode: Dry/Wet
• fully Wet
• no effect before or after

Occurs only when toggling ON.
Notable especially if this exact same iso is used as EQ for the playing deck and High and Mid are fully killed (with knob) both in the mixer and the standard effect unit.

No buffer underruns.
Doesn't matter which keylock engine is used.

Loudness seems to vary. When I tried to reproduce after start, the first pop was rather quiet, on further toggling pops where significantly louder but still with some variation in loudness.

FWIW pops also occur when changing the keylock engine.

personal branch based on main 2.5-alpha, no patches related to effects.

Version

2.5-alpha

OS

No response

[ronso0]

Very strange:
with a different DAC and different PA I can't reproduce.
Same Mixxx binary, same effects setup.

Maybe it's just some frequencies in the top range that slip through, and they are somehow filtered by my second setup?

[daschuer]

I can confirm a pop when you kill all and then enable the effect.

I will look into this.

[ronso0]

I've found this comment which I see no evidence for.
In getManifest() above, there is pManifest->setEffectRampsFromDry(true);
(but I'm not into effect processing so this might be a dead end)

mixxx/src/effects/backends/builtin/bessel8lvmixeqeffect.cpp

Line 57 in 08be88f

if (enableState == EffectEnableState::Disabling) {

[ronso0]

Oh right, next time I'll record audio issues to figure if it's Mixxx or a later part of the chain.

[daschuer]

A fix is here: #13073