Offline synthesis and WAV download
Use renderNote() to synthesize stereo PCM in memory, then encodeWav() to encode PCM16 WAV. No AudioContext is created, and no existing audio file is played.
The result includes the longest release and a short filter tail, so its length exceeds the note duration. Render again after changing settings; the download refers only to the last successful result.
Render result:
Diagnostics: