These options do not affect the Amiga emulation itself, but will affect how the Amiga audio is played back. Altering these options affect the quality and/or latency of the audio output.
Relevant options: audio_buffer_target_bytes
Audio Buffer Management
FS-UAE uses dynamic buffer management to try and keep the average fill of the audio buffer at a certain point. It indirectly controls the buffer fill by slightly tweaking the playback frequency if the buffer fill grows or shrinks. The playback frequency is determined by a PID controller, so the system is somewhat similar to the way a thermostat or the cruise control of a car works.
The controller is configured so that the changes to the frequency are very small – and the buffer is corrected over time – so you should (hopefully) not be able to hear this. Currently, the PID controller values are hardcoded and can not be configured.
OpenAL Driver Settings
FS-UAE uses OpenAL to output audio. In most cases, the actual OpenAL implementation is OpenAL Soft, and you can tweak the behavior of the audio driver with an OpenAL configuration file. OpenAL can support several audio backends depending on your system.
By creating ~/.alsoftrc, you can configure which audio backend and device OpenAL uses for audio ouput, along with several other options. For example, you can tweak FS-UAE’s internal audio buffering with audio_buffer_target_bytes, but you need to configure OpenAL separately if you want to tweak its internal buffers.
See alsoftrc.sample for documentation.