[linux-audio-user] Your synth wishlist?

[Chris Cannam]

I'm going to reply to a few emails in one go here and then drop out of 
the thread, because I don't think this is on-topic for LAU any more.  
If you want to reply further it might be worth taking it to LAD (or 
even the dssi-devel list on SourceForge -- so far unused -- though I 
don't think that's really the right place for philosophical 
discussions about the nature of plugins, more just for practical 
implementation stuff).

On Friday 30 Jul 2004 7:22 pm, Dave Robillard wrote:
> -- I'm not sure I agree with this "move the synth into the app"
> thing..

I agree with it in certain instances.  I think a synth plugin format 
is very appropriate for "small" synths, or for synths that (like most 
VST instruments) are designed to produce a particular recognisable 
sound.  If you have a decent standalone JACK host as well (and the 
DSSI example host is not quite good enough yet -- it doesn't do a 
very good job of dejittering the timing of incoming events) then you 
have all you need to write a simple plugin and have it work all ways.  
That's the thing I really like -- the possibility of writing it once 
and using it in many different ways, which using a plugin API 
permits.

I don't however particularly think you should attempt to make a real 
modular synth into a DSSI plugin.  Anything where the GUI is designed 
to do serious editing work, rather than just tweaking a few values, 
is IMHO probably not a great fit.

> If MuSE and similar apps
> just had intuitive GUIs for running their audio through jack apps,
> maybe they wouldn't need to assimilate everything and attempt to
> become Cubase.

Using external soft synths (JACK/ALSA style) for a sequencer like this 
is at the moment rather hard to do in a user-friendly way, for 
various reasons (some of which are outlined in the DSSI RFC).  It's 
great to be able to do it at all, but it's better to have a choice.

> If the "Cubase approach" becomes the norm,
> this will go away - put it in MuSE (or whatever) or forget it

I just don't think that will happen.  Even as a developer of one of 
the other Cubase-alike applications, I think there's just too much 
flexibility there: the fact that Rosegarden plugs into a JACK graph 
so you can use and sync it with freqtweak, Ardour, jack-rack, JAMin 
etc is of huge benefit to users of Rosegarden just as it would be to 
any other application.  This communication ability is an area in 
which Linux apps are better than Windows ones, and that benefits all 
kinds of applications equally.

> I don't see any benefits of moving all the synths into sequencers

Not "all" the synths.  But there are definite benefits to users of 
sequencers of having synths that can plug tightly into them.

> Is it possible to write a DSSI plugin that runs LADSPA plugins
> (loads libraries and whatnot)?

Yes, I think so, just as you can write LADSPA plugins that load LADSPA 
plugins.

> The first "D" in DSSI is a little disconcerting.  How much effort
> should I/we really invest in DSSI?

My view is that for writing plugins, there's rather little effort 
involved (other than the work you'd be doing to write the synth 
anyway).  DSSI hosts are much harder to write, which is the way it 
should be.  I personally have no great interest in waiting for GMPI 
just so I can have synth plugins in my sequencer, but GMPI should 
certainly offer some more interesting stuff (e.g. DSSI lacks any way 
to invoke notes at frequency rather than simple MIDI pitch, etc).

> I never understood why you chose
> to make DSSI "soft synth" specific to be honest.

Because it originally arose from a desire to use soft synths in 
plugins, because we wanted to constrain the requirements to things 
likely to be useful for straightforward synths, and because it was 
easier to describe and (if you like) sell the idea than if we called 
it an extension of LADSPA.  There's just too much flameage in 
extensions of LADSPA.  DSSI is a take-it-or-leave it thing that just 
happens to have LADSPA plugin technology in it.

> Is there any reason not to create DSSI modules with no
> MIDI support?

No reason.  Although actually you could probably also create pure 
LADSPA plugins and use DSSI-style GUIs with them with a suitably 
aware host.  I _think_ that Rosegarden 0.9.9 will happily start up a 
DSSI GUI for a LADSPA plugin as well as a DSSI one if it happens to 
find one -- I haven't tested it, but the code shouldn't care what 
sort of plugin it is.


Chris