I made a simple distortion effect plugin that contains a high-pass filter (juce::IIRFilter) which is always active with a default cutoff of 20Hz (the cutoff value is controlled through the GUI).
When I load an instance of my plugin in my VST host, everything works fine. However, if I load another instance of the same plugin in the host (even in another mixer channel), the output sound of the two plugins get crackling and noisy
This problem happens in Ableton as well as FL Studio (I don't have other hosts to test it though).
If I remove the high-pass processing code part (the call to "processSamples()"), then the output is clean so the issue has te be related to the filters I use.
I'm pretty new to VST development and I don't know if it's related to thread management or maybe there's something missing in my filters setup...I hope you guys will be able to give me some hints.
Thank you for you help !