How do I enable portamento and legato?

[Andrei-Tache]

Hello! I'm trying to get a smooth transitions between notes, but I haven't been able to figure out how to do it.

What I want is to play a note (ex C4) and then have it smoothly transition to another note (like C5), without triggering the release or attack of the individual notes. I would need this sound good over large note changes, so pitch bending wouldn't work. (Unless it was only used during the transition and the final note would play without bending)

I saw that fluidsynth has support for legato and portamento, which I think is what I need, but I couldn't figure out how to enable them. I tried sending CC 126 and 127 for mono and legato, as well as CC 65 and 5 for portamento, but when I play the notes they play normally, even if I slightly overlap them.

Sorry if this is a basic question, but I have gotten quite stuck and would appreciate some help :)

[derselbst]

Have you tried to comprehend the example leg_por_00.txt found here? It's a config file which automatically executes several commands in fluidsynth's shell, to be used with the -f parameter.

Pay attention when sending CCs 126 and 127: They must be sent on the basic channel (which should be channel 0 by default), otherwise they are ignored. There's is also a PDF in that directory which explains this in detail.

[Andrei-Tache]

Thanks, that did it! Turns out I needed to use set_legato_mode 1 and cc 0 68 127.

But I notice that when going between certain notes (like between 77 and 78 on the violin preset for the soundfont in the example) the attack and release are still heard, even though it's played legato for other notes. I would guess this is because the soundfont switches its sample at that point (?), but I have no clue. Is there a way to have these notes still play legato?

[derselbst]

I would guess this is because the soundfont switches its sample at that point

Yes, legato will definitely be interrupted when changing samples. I think it might even be interrupted in general whenever it leaves an instrument zone and enters a new zone (i.e. even while not changing the sample). Not quite sure though, I'd need to study the code to tell exactly, no time currently though.

[Andrei-Tache]

Yes, legato will definitely be interrupted when changing samples. I think it might even be interrupted in general whenever it leaves an instrument zone and enters a new zone (i.e. even while not changing the sample). Not quite sure though, I'd need to study the code to tell exactly, no time currently though.

I see... Do you know of a way to get around this and still have the notes play legato? I'm trying to let the user control the instrument and the switching is very jarring :/

[derselbst]

You'll need to carefully select the Soundfont to use or edit an existing one, sry.

[Andrei-Tache]

Mm, bummer, was hoping for something that could apply to any generic font the user loaded. Thank you for your help tho!