[iiwusynth-devel] Re: Pitch bend, filter, sysex, LADSPA,...

[Josh Green]

On Sat, 2002-04-06 at 09:11, M. Nentwig wrote:

<cut>

> =========LADSPA effect unit=========
> In my opinion, the LADSPA code is now good enough to include it.
> Several small changes are made in the configuration files, there is now
> an option --enable-ladspa (default=no) available for ./configure.
> I have written a small perl-Tk script, that shows a couple of sliders in
> a window, which allow real-time control of effect parameters (chorus,
> reverb, overdrive,...)
> This is not included, but if anybody would like to try, I can make a
> 'bundle' (soundfont, plugins, script).
> 

I'm curious about your LADSPA code. Is this a host? I've seen the LADSPA
iiwusynth plugin client code in the iiwusynth source tree, but I have a
feeling your talking about something else. If this is a host that allows
LADSPA plugins to be added to the iiwusynth chain than, cool! I'd like
to give it a try. This is one area where iiwusynth could be made really
pluggable, if one could choose which LADSPA plugin to handle chorus for
instance, and the control ports were modulated by iiwusynth.. Neato..

> ========Pitch bend=====
> There was a problem in the code handling program change events: a
> 'break' was missing, a pitch bend event resulted for each program change
> (to the wrong pitch). This was right in an older version (was one of my
> patches involved here? nooooooo :-), now it works again.
> Also, pitch bend default is now 0x2000 (center).
> 

Nice find :)

> 
> ========Signal to soundcard=======
> The signal is now clipped for positive and negative peaks. Currently,
> clipping produces a message (one might argue that clipping deserves an
> error message...).
> Same in the 'float' code, but untested due to the lack of suitable
> hardware.

Rock on.

> =========Bank select============
> My own masterkeyboard sends a bank change with each program change. This
> is completely useless for controlling iiwusynth. I have therefore
> included a switch (set with #define MN_CUSTOMIZED), that disables bank
> switching through the MIDI input, and prints a warning. Command line
> bank switching (select) still works. But since the switch is not set
> anywhere, this will not affect other users anyway.
> 

Is it completely useless? You can have different bank numbers for
presets loaded into iiwusynth. I'm not sure I understand why this would
be useless. If you have more than 128 presets in a sound font, you have
to use the bank change parameter to get access to the other presets.

> 
> =========Gain=================
> Changed the max-limit to 5. There are some rather 'quiet' soundfonts out
> there, which would need a boost. And, together with the LADSPA limiter
> set to a soft curve, it helps to get a nice, warm overdrive sound. And
> an incredible volume level, when compared to the 'clean' sound, just
> below clipping.
> By the way: The limiter is finished, documented and ready-to-go. Is
> anybody interested in the LADSPA plugin?
> 
> This is quite a lot of stuff, I hope I don't keep you too busy. Please
> let me know, if there are any problems, of if something should be solved
> differently.
> 
> Then, I tried Swami today for the first time, and after having an
> extended jam session on my (computer) keyboard I must say that I like
> it.
> 

What would be really cool next is to implement real time modulation of
as many of the sound font parameters as possible :) Sound font
modulators could then be implimented on top of this. How easy would it
be to do this? (Peter?) I've seen a bunch of modulator code in
iiwusynth, but I'm not sure as to how close it is to working.
A problem I can see with real time modulation of effects is in how the
API would allow the selection of a voice (in a preset). Perhaps a
function could be added like:

iiwu_voice_offset_effect (synth, channel, voice_number, gen_id, amount)

Since iiwusynth has no idea about the sound font layers (preset, preset
zones, instrument, instrument zones) when using the sfloader API, it
would be up to Swami to re-calculate what voices need to be offset. I
suppose something like a iiwu_voice_offset_effect_global routine would
be nice too to offset all voices on a particular MIDI channel.

> And now I'll go down to the bomb shelter and play some music.
> 

Is this for your own protection, or the protection of your neighbors? :)

> Cheers
> 
> Markus

Lates.
        Josh Green