Josh Green wrote:
I'm not very familiar with this control myself. What parameter of the
sound should this actually control? Brightness doesn't seem that
descriptive to me, but I have a limited vocabulary when it comes to
musical terms. I don't remember seeing this as part of the SoundFont
standard, which doesn't necessarily mean that it shouldn't be added to
FluidSynth though. If you have any more details it might help in
answering your question better :)
I think that it's essentially just a low-pass (or treble-cut) filter with a
variable cut-off frequency. As the cut-off frequency is reduced, so the upper
harmonics of the sound are increasingly attenuated, thereby making the sound
seem more 'muffled' - or less 'bright', hence the term 'brightness'. The
cut-off frequency is proportional in some way to the 3rd byte of the MIDI
message, i.e., 0=lowest cut-off frequency (very muffled) and 127=highest cut-off
frequency (not muffled at all). I suppose that one could liken its effect to
the 'tone control' knob that used to appear on those 2-valve record-player
amplifiers popular in the 1960s!
In my present application. I'm trying to replicate the effect of sounds coming
out of a large thick wooden box which has a set of shutters on the front, rather
like a venetian blind. When the shutters are wide open, the sound obviously
comes out more freely; as the shutters close more, the sound grows increasingly
quiet and muffled.
The intention is to send pairs of control/mode change messages to Fluid to
achieve this: '176 7 nn' to control channel volume and '176 74 nn' to control
the brightness (muffled effect). The instigator of the application that
generates these MIDI messages uses it with Creative soundcards and it apparently
works with those.
Hope this helps? I'd hoped that there might be a MIDI spec out there somewhere
that would define the range of cut-off frequencies available for this function
but a bit of Googling just now didn't seem to reveal anything specific.
Cheers,
Gerald.
_______________________________________________
fluid-dev mailing list
[email protected]
http://lists.nongnu.org/mailman/listinfo/fluid-dev
