[ardour-users] sync timing

Robin Gareus robin at gareus.org
Tue Sep 19 11:27:55 PDT 2006

Ferenc Wagner wrote:
> I'm trying to overdub some earlier material recorded in Ardour 0.99.3
> by a drum track created by Hydrogen. Ardour's sync setting was
> "internal" during the past recording sessions, now I had to change
> that to "Jack" to get Ardour and Hydrogen synced. All seems well, 
> except that the drum beats from Hydrogen sound a little bit early 
> -- inserting a delay plugin into the drum bus set equal to the
> latency announced by Ardour make things sound actually right.

I don't think changing the sync source matters but having a different
effect setup matters. I once stumbled over that issue and worked around
it by inserting a delay line, too.

> So, where is the truth now?  Is my recording late with respect to the
> bar lines etc. provided by ardour, and should I nudge the whole thing
> backwards?  Or is the previous recording right on beat? 

Truth depends on the 'ear of beholder' - have you got your ears on the
speakers or your eyes on the jack-buffer?

jack + ardour have a feature called latency compensation. which AFAIK is
not (yet) implemented in hydrogen.

I think it was the other way round: ardour is early - as it compensates
for the delay of the soundcard playing the buffer. To complicate things,
some Plugins report their latency incorrectly...

> Do I have to
> manually adjust the Hydrogen delay to the period size (latency) of the
> current Jack setup?  

Bus-input clients are expected to honor jack_port_get_latency (which
hydrogen-0.9.3 does not). So I dare say you have to manually adjust
until hydrogen and/or the plugins that you're using are fixed.

I'm not sure if using an ardour track instead of a bus might help.
You can work-around by adding some (bypassed?) Plugins to the
hydrogen-track in ardour, that will "do the latency-compensation" for
you :)


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