Softsynths are an unavoidable part of music production today; while they lack the hands-on feel you only get with
hired goons hardware synths, they’re very good at certain jobs, and if nothing else, they give you new sound options for costs as low as $0. Linux has some great softsynths at hand, like Hydrogen, a great drum synth and pattern editor that I’ve mentioned a few times recently, and some more general-purpose synths like Hexter, a DX7 emulation, and FluidSynth, a SoundFont synth for sampled sounds.
There are some good analogue-style synths as well, like XSynth and the self-described mongrel synth WhySynth, which combines bits from a bunch of other projects. Where these fall down, though, is in control and automation.
If I play something on the CS2x or Blofeld and record it in to Rosegarden via MIDI, everything gets recorded in, including any control messages from realtime knob-twiddling, and those messages are all reproduced on playback. That should work for softsynths, too, but neither XSynth or WhySynth respond to MIDI CC messages, so there’s no way to control aspects of the sound from a MIDI controller. Theoretically, Rosegarden should be able to control any synth parameter via DSSI, just like Ardour can automate paramaters on LADSPA effects, but Rosegarden doesn’t have an automation framework, and with its port to Qt 4 slowing any forward progress, it’s unlikely to gain one any time soon.
I’m not sure where the solution lies, then. I’d love to see XSynth and WhySynth listening for MIDI CC messages — most VST softsynths on Windows certainly do — but you could certainly argue that it’s a waste of effort when DSSI already allows full parameter control with an appropriate host. An external host like Jost could help, but it’s a bit silly having plugin synths if you have to run them outside of your sequencer. Unless Rosegarden can get past this Qt 4 bump quickly, Ardour might beat it to the punch if it can bring its existing automation support over to its fledgling MIDI support, due to arrive in version 3.