Ok, so I turned acpi off, but everything remained the same.
However, with acpi off, but "load-module module-alsa-sink tsched=0" commented out (see attached log), the rapid crackling actually seemed to be gone, but when I would skip around a track it would sometimes go quiet, and changing the volume using volume control in the panel caused the same loud buzzing noise as it did before.
Ok, so I turned acpi off, but everything remained the same.
However, with acpi off, but "load-module module-alsa-sink tsched=0" commented out (see attached log), the rapid crackling actually seemed to be gone, but when I would skip around a track it would sometimes go quiet, and changing the volume using volume control in the panel caused the same loud buzzing noise as it did before.