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BelaPlatform / bela-image-builder

Scripts to build a Bela image from scratch
MIT License
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More of a question: Seeing a large (6-9dB) difference in low frequency gain on the inputs between v3.8h and v3.8a #106

Open exitrip opened 5 months ago

exitrip commented 5 months ago

Our supercollider patch is a whole lot more sensitive to our pickup on v3.8a (PGA set to +5dB) than the exact same deployment on v3.8g/h (Input Gain at +10dB).

I haven't done a full frequency test, but it's very noticeable sub 400Hz. What changed? I'd like to stay up to date, but my client definitely can't afford the debugging.

Any leads would be helpful. What can I use en lieu of alsamixer/ctrl to inspect lower level driver settings?

giuliomoro commented 5 months ago

Did you try both versions on the exact same Bela cape? I.e.: is it a software or hardware difference?

exitrip commented 5 months ago

I did A/B testing swapping SD-Cards between two different Bela Mini's in the exact same hardware and multiple re-installations. The issue was first noticed "following the SD CARD" and the only thing I can trace it to is image version.

giuliomoro commented 5 months ago

thing is image version doesn't really mean anything in terms of supercollider version. Each image will come with a default supercollider version, but that can be upgraded at any time later when updating the Bela core code. What may be happening is that the input gain handling in the Bela core code has been updated at the end of 2021, and Sc hasn't been updated to follow it and isn't working as expected. I think if you create a file /root/.bela/belaconfig on the board and place this line in it: CL=--verbose , this may add (a lot) of debugging prints when scsynth starts, which may help narrowing down the issue.