Re: [LAU] Sound card for recording guitar

With USB devices, the period boundaries (where interrupts are supposed to happen) are not necessarily coincident with the USB frame boundaries (where interrupts actually happen). This results in delays (jitter) of up to 1 ms in the timing of period interrupts; with very small buffer sizes, this increases the risk of underruns greatly. So if, e.g., the machine is not able to handle "-p 64 -n 2" reliably, increasing the number of periods to 3 results in lower latency (3*64=192) than increasing the period size (2*128=256). (Using "-p 96 -n 2" would have the same latency, but works only if that particular Jack version allows period sizes that are not a power of two.)