Optimizing latency via JACK

Installation & Configuration Linux
#1

Hi there,

I’ve got some problems adjusting the latency compensation for JACK+Ardour.

I’m using Ardour 3, Ubuntu Studio and an Edirol UA-25 soundcard. JACK settings: Frames/Period 1024; Periods/Puffer 2.

I’ve measured the latency via jack_delay;

3251.767 frames 73.736 ms

There are contrasting opinions on what jack_delay already calculates and on what I have to subtract.

I already thought about doing the following:
3252-(2*1024) = 1204
-> input latency 602
-> output latency 602

Is this correct?

Regards
Max

#2

If you let Ardour 3.5 start JACK it can do the calibration for you automatically.

If you run jack_iodelay (which is part of JACK) rather than jack_delay (its ancestor) it will do the math for you automatically.

If you do neither of those, then you need to do the math you did above, which is correct.

#3

Thanks Paul!

If I use the jack_delay calculation (602/602) and if I don’t explicitly prompt Ardour 3.5 to do the calibration, it won’t compensate it twice, will it?

Regards,
Max