Re: [fluid-dev] [Rosegarden-devel] Problems With Rosegarden Using Qsynth or Fluidsynth When Using PulseAudio Instead Of JACK

[Aere Greenway]

On 01/31/2013 01:38 AM, Holger Marzen wrote:
> On Wed, 30 Jan 2013, Aere Greenway wrote:
>
> > On 01/30/2013 12:33 AM, Holger Marzen wrote:
> > > On Tue, 29 Jan 2013, Aere Greenway wrote:
> > >
> > > > Rosegarden and Fluidsynth Developers:
> > > >
> > > > In working with Fluidsynth problems, the Fluidsynth developers have
> > > > wondered why I insist on using JACK with Qsynth, rather than just
> > > > configuring it to use PulseAudio.  Yesterday I finally found out why I
> > > > do this, but what the cause of the problem is, possibly both sets of
> > > > developers (together) might be able to postulate.
> > > >
> > > > Here are the steps of a test you can do to illustrate the problem:
> > > >
> > > > 1. Configure Qsynth to use "pulseaudio" instead of "jack".  Even doing
> > > > this can cause hangs if you have more than one engine configured.  Best
> > > > approach is to not restart the engine when it prompts you, instead,
> > > > terminating Qsynth, and bring it back up after completing the
> > > > configuration changes.
> > > Using Pulse and JACK works here by disabling Pulseaudio clients to start
> > > it (autospawn = no in /etc/pulse/client.conf) and starting Pulseaudio in
> > > QjackCtl. See http://www.marzen.de/Holger/pulseaudio_and_jack/
> > >
> > > Fluidsynth is available as a DSSI module to be used in Rosegarden. No
> > > problems at all AND lower latencies.
> > Holger:
> >
> > Thank you very much for the information.  It could help me a lot.  I will save
> > it for reference.
> >
> > I have tested the Fluidsynth DSSI before.  It seemed to work fine, but it
> > seemed to me there was a lot of per-track special setup I had to do in order
> > to use it.  Qsynth seems to work better for me, but perhaps it's because I
> > have vanquished one set of demons, and have not worked long enough to defeat
> > the other set.
> I use Fluidsynth-DSSI because *everything* important is stored when
> Rosegarden writes its .rg-file. Different soundfonts, different
> instruments... no problem. I use separate instances of Fluidsynth-DSSI
> for bass drum, snare, left tom and so on.
>
> Specially for drum and bass sounds you won't notice any latency or
> jitter. Rosegarden and DSSI-plugins (Fluidsynth-DSSI, Hexter, Whysynth)
> is a very good combination when you need exact timings.
>
> If you have more than 15 instruments/instances then you have to
> recompile Fluidsynth-DSSI and change
> #define FSD_CHANNEL_COUNT  25
> in fluidsynth-dssi.h
>
> 24 because Rosegarden allows 24 synth plugin instruments and "plus 1"
> because of a strange initialization race condition. If FSD_CHANNEL_COUNT
> is set to N then the Nth instrument isn't restored when loading the
> .rg-file.
>
> Best regards
> Holger
Holger:

Thank you once again for some very useful information.

The "different soundfonts" aspect of it especially caught my attention.

I have been dealing with that by having two Qsynth 'engines', which in 
effect, supplies two separate synhesizers, each with 16 channels, and 
(in my case) using different soundfonts.  But that only gives you two 
soundfonts.  I have used three Qsynth 'engines' successfully.

I think I will re-visit using the Fluidsynth-DSSI, if only as another 
tool in creating music.

It would be more useful to me if there were a way of firing up a 
collection of DSSI instruments, each with their own configuration 
restored (and saved), that I could access using the ALSA sequencer 
interface.

-- Sincerely, Aere