Re: [fluid-dev] Limited dynamic in fluidsynth

[Josh Green]

On Sat, 2008-07-05 at 17:29 +0200, senjin wrote:
> I'm new to the list, so hello everybody!
> I'm not English native speaker so sorry for the mistakes...
> 
> I use fluidsynth 1.0.8 with qsynth 0.3.2. I noticed the following 
> problem: When I play my electric piano connected via MIDI to the PC the 
> dynamic range of the sounds played by fluidsynth is very low - much 
> lower than of the sounds from the audio output of my piano. All the 
> notes from fluidsynth have very similar loudness.
> 
> I noticed the problem using two popular soundfonts: naturalstudio 
> ns_kit7free drumkit and FluidR3GM.SF2, so I doubt that this is a problem 
> with my soundfonts.
> 
> I'm not soundfont expert, but some time ago I read that there are two 
> ways of assigning sample dynamic to MIDI velocity values: linear and 
> logarithmic. Some soundfonts require one, some another. Using the wrong 
> one leads to wrong dynamic. I guess that this is the source of the problem.
> 
> However I couldn't find in qsynth nor in fluidsynth an option to chose 
> the dynamic mode. Is it implemented?
> 

Hello.  FluidSynth doesn't currently have a linear versus logarithmic
velocity setting.  I'm not certain exactly what this would entail
either, in relation to the SoundFont specification.  It does sound like
an issue worth looking into.  I've been meaning to put FluidSynth
through specification conformance tests to make sure its performing as
expected.  This has not yet been done though, so I imagine there very
well could be issues with the current velocity curve.  If you find any
more information about linear versus logarithmic SoundFont velocity
mapping, I'd be very interested in reading up on it.

It could also be useful to look at what kind of velocity values your
keyboard is sending.  If you are using the ALSA sequencer, you could
start up aseqdump and connect your keyboard port to it and see what kind
of velocity values get sent at different velocities.

Best regards,
        Josh Green