I followed the advice for using PulseAudio to solve this problem. I have worked with a couple of Linux software synthesizers like Amsynth, ZynAddSubFX, and Yoshimi and they are really capable synthesizers in terms of creating many various sounds.
But how do I record these sounds? Do I have to record them with a microphone? That just does not seem right. I have seen some options to forward their MIDI output to other software like LMMS, but it just gives the notes, not the sound (timbre).
Also, I have seen no option in these synthesizers to record the sound being played to an audio file. So, how are standalone software synthesizers (excluding those that have become integrated in other software like LMMS or Ardour) recorded?
If I want to record the audio from the synth to a separate track while I play along with a file that I have loaded in audacity, can I do so without having the file I am playing with be re-recorded into the same track as the synth? It's difficult to edit when the synth lead I have recorded is all on the same track.