alignment and latency

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in0giro
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Joined: 2009-07-04
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ahoy all,

first, thanks to Paul/developers/etc. for all their work. Ardour, along with the community around it, is very inspiring. so much so, in addition to new material, i have started re-recording/transferring unreleased work done in Logic 7 to Ardour (2.x linux) and other FLOSS tools. i believe strongly in free/open culture/software, and hope to support projects like this with my music (i.e. "made with Ardour/FLOSS/etc."), as others have already done.

ok, the question: what is "Alignment" on the context/pop-up menu of a track? it has 2 selections: "align with capture time" and "align with existing material". i have search the site/manual/etc. but have not found too much information about this. is there a normal setting for this? would this cause incorrect latency compensation on resulting tracks?

i am having some latency compensation/monitoring trouble on project in Ardour that i have not experienced before. perhaps because it is my biggest project yet (track-wise). either way, i have been trying various solutions and i came across this.

thanks, w

details:
MacBook (first generation) Core Duo @ 2.0 GHz, 2 GB RAM
Edirol FA-66 (FireWire)
recording to external 7200 ATA drive over same FireWire bus
Ardour 2.8.1 (Ubuntu Studio Hardy 8.04)

peder
User offline. Last seen 49 weeks 4 days ago. Offline
Joined: 2007-05-08
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You missed the obvious solution: google it!
The ninth hit (and the first four were bug reports and cvs info) led to Wolfgang Wohel explaining:
Look at the ardour track's alignment settings (right click on the
track header). Recording from a jack client on the same box (hydrogen
in your case) this should be set to "Align with capture time". Ardour
does that automatically when you connect something to the track's
inputs. So usually things should just work. Maybe there's a bug
sitting that borks this when a track's inputs get changed a couple of
times ...
Keyword is ardour's latency compensation. In relation to ardour's
timeline there is a timing difference between audio from a client like
hydrogen (its audio reaches ardour's inputs within the same period
that ardour produces the audio it relates to) and audio from
external/physical inputs (this audio reaches ardour's inputs 1 chain
of periods later in relation to the audio you play along to -- you
know, Absolute Time: ardour plays beat 1 -> depending on your period
settings this audio spends time on the way out -> now you hear beat 1,
play along -> your playing along spends time on the way in -> ardour
shifts the incoming audio to "Align with existing material").

So, depending on how you connect/record things that should be automagically set for you.

in0giro
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Joined: 2009-07-04
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thanks for the reply. i was using Google search, but only within in the ardour.org site, not in general. i do it so often i forgot to remove the site:ardour.org command.

perhaps i am having this problem of the Alignment either switching or not being correct. perhaps when i upgraded to 2.8.1. i will test it tomorrow and report back.

thanks again and sorry for missing the obvious.

peace

in0giro
User offline. Last seen 22 weeks 2 days ago. Offline
Joined: 2009-07-04
Posts:

ahoy again,

ok, the track's Alignment does not seem to be the problem as everything looks to be automatically set correctly:

+ tracks that are recording from the external FireWire interface are set to "Align with existing material"
+ tracks that are recording from software JACK clients are set to "Align with capture time"

i will create a new thread once i have more information on my issues and try some solutions i have found in the meantime. basically, when using hardware monitoring, with Ardour reporting 2.7 ms latency, playback of recorded audio is not in sync. whether this is because of latency compensation messing up, FireWire reporting incorrect latency, too many tracks, 2.8.1, etc., i do not know yet. also, this problem may have always been happening to me, as my first projects with Ardour were smaller, thus i could get away with a buffer of 64 and 128. with 256, perhaps the effect is now noticeable because of the higher latency.

thanks again.

PS. search Google with "ardour alignment", i could not find the post you reference above, even when i include the author's name!? thanks for including the text.

peder
User offline. Last seen 49 weeks 4 days ago. Offline
Joined: 2007-05-08
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search Google with "ardour alignment", i could not find the post

Hehe, I was a bit more clever and searced for ardour "align with capture time"