A couple posts ago, I cooed with joy over discovering Seq24. And last post, I pointed out SFXR (now in twilight development status) for producing simple low-fi sound effects. Now here is an app which is pretty capable at most of what SFXR does, and works as a Seq24 plugin as well.
amsynth is a cool little synthesizer desktop app all by itself. It can also be used, like Hexter, Wsynth, and xsynth, as a DSSI plugin for Seq24 modules - just start a copy of each, and set one (or more) loops to amsynth's output. And it looks cool doing it.
While AMSynth (which I've just decided to capitalize that way because it looks righter) doesn't have a full orchestra of instruments at your disposal like Hexter.so does, it is far easier to customize. To make your own instrument, just select 'new preset' from the preset menu, hit 'Ctrl-R' a few times and audition each result to hear the random sound, and stop when you find a sound close to what you want, then tweak the knobs on it (by clicking with the mouse and dragging up or down) to get it how you want it, then name it with 'rename preset' in the presets menu again, and finally click 'save' right next to the presets dropdown menu. You'll now find your new preset in the menu, and it will reload each time you start AMSynth. So this way you can build up your own personal library of sound effects.
It's also easy to copy / paste and edit presets from the plain text file. Open ".amSynth.presets" in your home directory; there's the list of all available sounds, including the ones you save. Easy to copy and share! You'll also notice that at the bottom, AMSynth seems to save a lot of 'new preset' instances, which you might want to delete here as they don't show up in the menu anyway.
Here's a more complete tutorial on AMSynth, though very outdated and using and older version.
Here's my own preset discovery, which I named 'night frogs' in my preset file:
<preset> <name> night frogs <parameter> amp_attack 0.101708 <parameter> amp_decay 1.98257 <parameter> amp_sustain 0.28707 <parameter> amp_release 0.930455 <parameter> osc1_waveform 2 <parameter> filter_attack 0.538419 <parameter> filter_decay 1.77124 <parameter> filter_sustain 0.141512 <parameter> filter_release 0.962746 <parameter> filter_resonance 0.149043 <parameter> filter_env_amount 0.957702 <parameter> filter_cutoff 0.51926 <parameter> osc2_detune 0.0872381 <parameter> osc2_waveform 1 <parameter> master_vol 1 <parameter> lfo_freq 5.02726 <parameter> lfo_waveform 2 <parameter> osc2_range 2 <parameter> osc_mix 0.176455 <parameter> freq_mod_amount 0.810294 <parameter> filter_mod_amount 0.595398 <parameter> amp_mod_amount 0.22656 <parameter> osc_mix_mode 0 <parameter> osc1_pulsewidth 0.691587 <parameter> osc2_pulsewidth 0.576662 <parameter> reverb_roomsize 0.433333 <parameter> reverb_damp 0.473445 <parameter> reverb_wet 0.42621 <parameter> reverb_width 0.829504 <parameter> distortion_crunch 0.327175 <parameter> osc2_sync
As seems to be par for the course for FOSS audio engineering software, documentation is minimal to none, the project appears
abandoned, and is barely a fuzzy rumor at best. Even the man page is a place-holder. The closest thing to developer-provided docs is in /usr/share/doc/amsynth/README, and that's 80 terse lines of bare clues.
Update: Whoa, nelly, the AMSynth team dropped by the comments to let us know they're live 'n' kicking, and there's going to be a 1.4 release with over 1000 sounds! Also drops this link, with demos you have to check out.
I've also discovered that AMSynth will export directly to .wav file, for just making sound effects and music accents like you would in SFXR. Nifty side feature.
Here's that 'night frogs' preset in action as part of this cruddy little attempt at an ambient noise track:
And while I'm dumping MP3s, here's a couple more I have monkeyed out while playing with Seq24:
Once again, be advised that I don't know music composition from my arse from my elbow. But if you find these useful, Creative Commons for your next game, video, or whatnot. And once again, I'm doing this not to pursue a career as a musician, but just so that when I need audio for future projects, I don't want to have to live in terror of the RIAA mafia for the rest of my life. Just five minutes of fidgeting produces my own track to do with what I please, and all those scary copyright phantoms just disappear in a puff of smoke. That's a good feeling.
By the by, here's the Wikipedia entry on synthesizers, which has some explanation of the sound audio jargon you wade into using programs like AMSynth. And here's further resources at the Linux musician's Wiki, hurray, they exist!