Re: [fluid-dev] MIDI control change - brightness

[Josh Green]

On Mon, 2005-06-20 at 08:41 +0100, Gerald Pye wrote:
>       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!
> 

Ahh, I was overlooking the fact that you are referring to a MIDI custom
controller, I thought it was NRPN/RPN at first.  I see now that 74 is
indeed referred to as brightness in a map of MIDI controllers.  This is
not actually part of the official SoundFont spec though.  Perhaps it
should be added if the Creative cards support it by default, though this
would be straying from the spec.

This effect can be easily achieved by adding a modulator.  Swami has
support for global modulators (which can be thought of as session
modulators, which don't actually get saved to files).  With modulators
you can use pretty much any MIDI controller to modulate almost all
SoundFont parameters (well useful ones anyways).

It sounds as if the brightness parameter is equivalent to the filter
cutoff, correct me if I'm wrong.

>       Cheers,
> 
>               Gerald.

Cheers.
        Josh