Evening out loudnesses of the internal synths

I've just updated LMMS to 1.0.95 from KXStudio repos.

I found the new Nescaline synth (another 8-bitter, eh?) and it's very loud.

Playing a single note is fine (but already touches yellow on the master waveform display), but playing a chord totally distorts on the mixer:

Compared to ZynAddSubFX's initial patch playing the same chord it's about 28 dB (!!!) louder.
That's quite chaotic. And I'm not complaining, that Zyn is quiet, I complain that other synths are loud ;)

I'd suggest discussing a way to even out the loudnes of the synths without breaking the backwards compatibility.

I propose changing the default presets (initial patches), so newly added synths sound at more consistens volume levels.

Another way is to add "Amplifier" plugins to the initial patches, that would compensate for the differences. This however might be more confusing to the users - but would look more elegant on the front (all volume levels at 100%).

I'm not saying they all should be so quiet as Zyn, I think we should pick something in the middle, like -12 dB RMS (btw: I see no way to measure this internally).

Take a look:

Download this project:
http://unfamusic.com/5h1+/unfa-InternalSynthsLoudnesses-01.mmpz

What say thou?

Start by reproducing the reported loudness difference with the attached unfa-InternalSynthsLoudnesses-01.mmpz project and compare the Nescaline and ZynAddSubFX initial patches. The target level, affected synths, compatibility requirements, and whether presets or amplifier plugins should change still need agreement before completion can be defined.

Written by the indexing model from the issue text.