Revisit final sound processing stages

[probonopd]

Continuation from #69 (comment):

Ah yes, I tried the compressor in the VLC media player, and it's getting louder there, when it is switched on. As I read it, @dcoredump wants to re-work the whole final signal processing stage (use floats instead of int16_t, pan, mixer, compressor, reverb), which makes absolutely sense to me. At the moment, each TG has its own compressor, and as I said earlier, my pan processing + mixer is not ideal. There is much room for improvement in it.

This ticket is a reminder that we revisit the way we set up and use limiter/anti-clipping, compressor, pan processing, and mixer once @dcoredump has re-worked the final signal processing stage. No hurries, just so that it won't be forgotten.

[dcoredump]

The signal chain is now completely in float32_t (until it gets converted for m_pSoundDevice->Write()) but I have some trouble with noise at the reverb tail. I don't have an idea where it is coming from or if it's (perhaps) only when using PWM as output?

I tried to compare it with @probonopd current version, but this one always gives me an assert(reverb) at startup. Can you try to checkout my current state (https://github.com/dcoredump/MiniDexed)?

[probonopd]

Thanks @dcoredump.

Yes, the Raspberry Pi headphone jack PWM is very noisy, especially on the older models. I don't have high hopes that we can do much about it. The only device where it is halfway ok is the Raspberry Pi 4 from my experience.

I tried to compare it with @probonopd current version, but this one always gives me an assert(reverb) at startup.

Are you saying that the build from https://github.com/probonopd/MiniDexed/releases/tag/continuous is crashing on your machine?

[probonopd]

Can you try to checkout my current state (https://github.com/dcoredump/MiniDexed)?

I have opened a PR, which normally triggers a build, which I then can test. Unfortunately there is a merge conflict; could you please have a look at it? If you can resolve the conflict in your branch, then it should start to build automagically :)

[rsta2]

I tried to compare it with @probonopd current version, but this one always gives me an assert(reverb) at startup.

My mistake, sorry. Put this line behind the creation of the AudioEffectPlateReverb object, and the assertion will go away.