LMMS Filters Pop and Often Cease to Output Audio

[Hey-Holokin]

If putting a filter or equalizer band to a frequency outside of a certain range (usually within lower numbers), the filter will occasionally "pop," becoming so loud as to push most audio outside of the maximum LMMS output. Occasionally, this issue will cause the filter or equalizer to break and halt all signal processing altogether.

Branch: stable-1.2
OS: Windows 10

[softrabbit]

Any filter in particular you'd like to single out for punishment? 😈

[curlymorphic]

@UnityParadox

Can you give clear instructions on how to reproduce this bug please

the instructions may look like this --

start new project
play a c2 on tipple oscillator
put the duel filter on , and set the lp to 20hz

Instructions like this this really makes bug fixing a lot easier.
I am aware these bi-quad filters can be brittle, but we need access how often this happens as to the solution I propose.

[musikBear]

propl. its the Infinite loud sound 'bug'

[Hey-Holokin]

@curlymorphic Any filter will reproduce the issue, however it seems that the bandpass filter plugins have the worst of the issue, with lowpass and highpass coming close second, being easier and more methodical to reproduce.

To reproduce:

Open a synth instance with any waveform.

Should ENV/LFO be enabled on this synth, go to the envelope list and turn the filter on. Alternatively, add a pass filter effect in the FX tab.

Perform a quick shift from generally anywhere above ~100Hz on the filter to 0. The popping/infinitely-loud-silence should occur immediately and take effect on all LMMS audio running at the time.

As for the native equalizer, raise a peak band to a high enough volume (and possibly frequency), and this should reproduce the complete halt of processing, silencing only the intstrument/plugin output.

[curlymorphic]

Having spent some time trying to reproduce this, I have failed,