Re: [fluid-dev] Fluid Synth CC1 Tremolo

Thus there is no way that midi channels are equivalent to FSchannels.

When talking to a MIDI compliant synthesizer the synthesizer must understand what is a MIDI channel. The semantic of int chan parameter of fluidsynth's API

is the same that the four channel bits in any of the MIDI event described by the MIDI specs. Any synthesizer, FS or another should react equivalent to this information.

The format of the data and the meaning of the data are two things different. The only difference is that fluidsynth is less restrictive that the MIDI specs (256 channels instead of

16 ). When using The MIDI driver, the MIDI information received on the MIDI input hardware (channel,note,velocity) is transmitted directly to the parameter of fluidsynth's MIDI API which react as described by the MIDI specs. How could we think that the documentation is wrong ?

From the description of eplayOrgan, it seems that the application is an interface between multiple physical keyboards (manuals) and fluidsynth instance(s).

Using 4 fluidsynth instances with 16 MIDI channel by instance means that eplayOrgan need to supply 4 x 16 = 64 MIDI Channels on its output. Please, is my understanding correct ?

>The notes from EACH incoming midi channel are fed simultaneously to 32 FSchannels for processing by the synths. (eplayOrgan actually uses four synths - one for each division).

1)Please, what could be the reason to map one incoming midi channel simultaneously to 32 distinct FSChannels ?

2)Are the 4 synths running on the same machine ?, and in this case what is the reason of using 4 instances on the same machine ?

Thanks for your comment. Even though the FS documentation is wrong and confusing when you consider midi and FSchannels I know you are not going to change it.

Your argument that these channels are equivalent may be right a simple case such as your command interface but when you consider an organ they most definately are not the same or even equivalent. And it is very confusing to think they are.

The midi inputs for eplayOrgan arrive in midi channels whether from a keyboards or midi files. There is ONE midi channel for each input. Each midi input is processed and then sent on to the synth. The notes from EACH incoming midi channel are fed simultaneously to 32 FSchannels for processing by the synths. (eplayOrgan actually uses four synths - one for each division).

Also midi channels contain midi events in a specified defined format. The FSchannels are driven by software procedures in a completely different specified format.

Thus there is no way that midi channels are equivalent to FSchannels.

Now the good news - Now I have changed the channels from midi channels to FSchannels, fluid_synth_cc(synth, FSchan, 1,100) now works and produces tremolo using the sound font Tom successfully tested.

I have learnt quite a bit about sound fonts - especially how their modulation system works. I hope to learn even more by experimenting now I have a working system to play with. So thank you all for your help.

Best Wishes

David (csw900)

On Sunday, 5 July 2020, 11:43:27 BST, Tom M. <tom.mbrt@googlemail.com> wrote:

There is no such thing as "FSchannels". The documentation of the synth always
talks about "midi channels". The only way you communicate with the synth is
via "midi channels". Just because the number of midi channels is limited to 16
in standard midi files does not mean it's limited in the same way for
fluidsynth. Neither does it mean something is "completely different".

JJC already pointed out how the number of channels can be changed, see
http://www.fluidsynth.org/api/fluidsettings.xml#synth.midi-channels

The naming "midi channels" was given to indicate that channels of a midi file
are semantically equivalent to the channels provided by the synthesizer.

> Just because something works from the command prompt does not necessarily
mean that it will work when another programmer tries to make it work

Since the command prompt uses the same synth API calls as you used in your
app, it is definitely suited as proof of concept.

Tom

From:	Ceresa Jean-Jacques
Subject:	Re: [fluid-dev] Fluid Synth CC1 Tremolo
Date:	Sun, 5 Jul 2020 19:11:59 +0200 (CEST)