Dumb question, why not disable interrupts during each iteration of the inner loop (+6 cycles per iteration = +42 cycles total)? Was the audio device using NMI?

Dumb question, why not disable interrupts during each iteration of the inner loop (+6 cycles per iteration = +42 cycles total)? Was the audio device using NMI? Or maybe the 224 cycles of that loop was too long a delay to respond to the interrupt?