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elk-audio / elk-pi

Elk Audio OS binary images for Raspberry Pi
https://elk.audio/
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MDA JX10 output silences in VST 2 version #1

Open stez-mind opened 4 years ago

stez-mind commented 4 years ago

Issue Description

When launching the included MDA Jx10 plugin in VST 2 version, voices go suddenly silent. Everything seems to be working fine with the VST 3 version.

Elk Audio OS version

0.6.0

Raspberry Pi Model

RPi3 B+

How to reproduce

Just launch any SUSHI configuration file that is using MDA JX10 in the distro, either with the internal arpeggiator/sequencer or connecting an external MIDI device.

stez-mind commented 4 years ago

This happened suddenly when reverting back to a 32bit toolchain.

Investigating the problem with GDB + traps for floating-point exceptions, it seems that the State Variable Filter blows up. The filter model is known to be unstable under certain parameters & modulations conditions.

I had the same problem on my native X86-64 machine and it thus seems that the algorithm itself is very sensitive to small changes in toolchain setup.

We tried building without any optimization without any luck for the RPi3 32 bit. Interestingly enough, the VST3 version works which has basically the same code apart from an added pan parameter...

The workaround for the moment is using the VST 3 version.