Even when a computer is programmed to pass an input signal flowing into
the sound interface input out of the sound interface output as fast as
possible, there is a delay or latency. This delay is typically
on the order of tens of milliseconds. Figure 5 shows
the impulse response measured on the PreSonus card. The latency is
approximately 62ms. The latency could have been decreased some by adjusting
software settings in pd. The impulse response also rings noticeably due to
the anti-aliasing filters.
Impulse response of the PreSonus FirePOD
sound interface when the channel 1 output is directly connected to the channel
1 line input
For reference, we provide the measured impulse response
shown in Figure 5.