[fluid-dev] RE: About multi ( >2 ) jack outputs

[Ken Ellinwood]

I've just played around with this.  It appears to works with caveats:

Do this:  fluidsynth -a jack --audio-channels=16 -o audio.jack.multi=yes

>From the looks of the code, the -j option (for auto-connecting the jack ports)
only connects up to two ports then drops out of the loop.  So the best bet
(until the code is fixed) is not to use the -j option, but to manually connect
the ports using jack_connect (use jack_lsp to list the available ports) or a
graphical patch bay like qjackconnect.  Each channel is routed to the
appropriate jack ports (without reverb or chorus).

It appears that all effects output is globally mixed and sent to the
fluidsynth:fxl_00 and fluidsynth:fxr_00 ports.  Note that fluidsynth is
creating 4 effect ports in the jack.multi scenario, but only the first two
appear to be used (this is regardless of the synth.effects-channels setting
value -- it appears to be ignored).

Anyway, this doesn't seem so bad.  In fact for recording this is good, it means
that each channel can be recorded into a seperate track for independent
manipulation in the "mix".

FYI, enabling audio.jack.mutli has no effect when used in FluidGUI -- the
setting option does appear to be passed to the fluidsynth command line, but
only the two regular jack ports are created.  I'm not sure why.

Ken


--- original message --- 
Giannis Gravezas wrote:

First of all hello and congratulations on your fine efforts.
Fluidsynth is quickly becoming the best sampler on the linux audio landscape .
The only thing that's been holding me from using it is the lack of
multi-channel output ( I'm oriented on techno-trance and use it for percussion
loops I need to be able to process each channel with different effects through
jack and other apps ) . I tried specifying --audio-channels , --audio-groups
and they didn't worked only two jack ports. Then browsing through the code I
found in fluid_jack.c the "jack.audio.multi" and set it to yes and alas 36
ports !!! (16 stero channels) Only thing is when I try to play something the
synth exits no matter what combination I try. I browsed the code a little and
seen that groups control the output but haven't browsed it extensively. Before
I continue has anyone actually used multiple jack output? I wan't to know if
I'm doing something wrong in my general setup before I try to understand how
fluidsynth works .
Thanx in advance,

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