Re: [fluid-dev] New patch: polyphonic key pressure (aftertouch)

From:

Marcus Weseloh

Subject:

Date:

Wed, 24 May 2017 01:22:10 +0200

Hi all,

I've added a test MIDI file and soundfont to the ticket:

https://sourceforge.net/p/fluidsynth/tickets/50/#b976

And Kjetil: if you really want to use the key pressure as volume control by default in a non-standard way, you could always hack the modulator into your fluidsynth copy. A patch is attached. It gives you Poly Pressure to Initial Modulation, in a positive concave unipolar mapping. That means that positive key pressure values reduce the initial volume of the sound (based on the velocity of the note on). So it's basically an inversed _expression_ controller, just on a single note. But I think something like that should really only be a hack and not part of FluidSynth... not even as a configuration option.

Cheers,

Marcus

2017-05-23 18:18 GMT+02:00 Marcus Weseloh <address@hidden>:

Hi Aere,

2017-05-23 16:47 GMT+02:00 Aere Greenway <address@hidden>:
> I have been using FluidSynth for years, by way of the Qsynth GUI interface, with a synthesizer having aftertouch (which it actually does by sending Channel Pressure MIDI control messages).
> It has always had the same effect as the modulation control message.
> With the FluidR3_GM soundfont (which comes with Qsynth as a dependency), the Modulation control often produces a non-pleasing sound, so I actually removed the Channel Pressure messages from my MIDI sequences.
> With other soundfonts, the Modulation messages (and therefore the Channel Pressure messages) are useful.
> It has had this behavior for over 10 years.
> Polyphonic Aftertouch may be different from Channel Pressure. I am talking about Channel Pressure, which my synthesizer uses.

Thank you very much for your feedback! Yes, most synthesizers implement only Channel Pressure for aftertouch (probably because Polyphonic aftertouch can generate an awful lot of messages on a keyboard). And the soundfont default for Channel Pressure messages is to affect the Vibrato LFO pitch depth, same as the modulation wheel. I can understand why you remove those messages when using the FluidR3 soundfont.

Polyphonic aftertouch is a completely different message, though. It's not mapped to a modulator by default and has the unique property that it affects single notes, not the whole channel. So with the right MIDI controller and soundfont, it can give you a lot of expressive power.

Cheers,

Marcus