[LAU] Testing JACK and PA latency

Moving this thread to LAU as it seems to be a more generic issue now: I am testing the round trip latency when using PA and JACK together. I have the following connection graph: jack_system (in) -> pa_source (in) -> audacity (in) -> audacity (out) -> pa sink (out) -> jack_system (out) Audacity is run in pass through mode with internal latency set to 0. I would like to measure the round trip latency from jack_system (in) to jack_system (out) This is a slightly unusual request but it is actually a reasonably important measurement in the bigger scheme of things. Does anyone have any suggestions? Ideally I would like to get accurate measurements for both input and output latency. input: jack_system (in) -> pa_source (in) -> audacity (in) output: audacity (out) -> pa sink (out) -> jack_system (out) So a tool that allowed me to measure the latency between every node on the graph would be perfect. Obviously made alot harder by mixing PA and JACK together. I have tried jack_iodelay but it does not measure the input signal from the mic instead it provides it's own signal. I suppose I could modify jack_iodelay to accept an input signal as the starting point for the latency graph but I have not looked into the code yet to see how tricky that would be. -- Patrick Shirkey Boost Hardware Ltd