Remember that the systemic latency for all USB audio devices on Linux can (and likely will) change every time the device is re-opened (re-used). This is  a feature (bug) of the kernel USB audio class device support.

On Sat, Mar 20, 2021 at 11:07 AM Lorenzo Sutton <lorenzofsutton@gmail.com> wrote:
Hi David, all,

Creating a new thread as the old one was pretty long...

On 19/03/2021 15:22, David Kastrup wrote:
[...]

 >> - Zoom H5 shows 4 inputs in jack: the L/R mics and the inputs 1 and 2
 >
 > Oh, can you just put the headphones right next to the mics (makes
 > astonishingly little difference in comparison to direct connections) and
 > use jack_iodelay for measuring out the latency of the H5 with your
 > settings?
 >
 > Numbers are surprisingly hard to come by for any audio interface.
 >

This is what I got by connecting jack_delay to one output and putting
the headphone right in front of the microphones (connected only one to
the jack_delay input). These are common jack settings I use or have used
with this device, although the 32 Frames is very unstable and the 64
Frames one gets a few xruns depending on what it's used with (but still
more usable). The 128 Frames settings is very stable.

    SR    Fr/p   Avg. delay reported (ms)
------+-------+-------------------------
48000
        128,2   22.7
        64,3    18.7
        32,3    14.2

44100
        128,2   25.2
        64,3    20.6

96000
        128,2   22.6
        64,3    18.6

88200
        64,3    18.6

Hope this is useful /interesting

Lorenzo.
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