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Re: synchronization of input and output



Hi Taylor

We don't know of any issues here, so can you file a bug report?

Thanks

Bill

On Oct 31, 2009, at 10:25 AM, Taylor Holliday wrote:

Interesting, upon rebooting the duet was in sync. Putting the computer
to sleep and waking it back up results in it being out of sync again.
Unplugging the duet and plugging it back in restores the
synchronization. The builtin audio was always out of sync.

Something's buggy!

- Taylor

On Fri, Oct 30, 2009 at 6:14 PM, Taylor Holliday <email@hidden> wrote:
On Fri, Oct 30, 2009 at 5:30 PM, Brian Willoughby <email@hidden > wrote:

On Oct 30, 2009, at 17:25, Taylor Holliday wrote:

It's hard to say. There isn't enough context here. You say everything is
"10
samples or so late", but late as compared to what?. And, is it 10 samples
all the time? If not, what precisely is the variance?


You need to define better what you are measuring and how you are doing it
before I can provide more information.

I'll try. In order to determine whether newly recorded audio is properly synchronized with previously recorded audio, I hooked the output of my duet into its input. Then recorded audio to a separate track. The newly recorded audio is 10 samples late relative to the audio being played back. The 10 samples seems to be a constant.


CoreAudio, and therefore Logic, only has the latency reported by the audio
driver to go on. If the Apogee Duet provides I/O latency values which are
off by 10 samples in total, then your test will be off by 10 samples.


Have you tested against other devices? What about the built-in audio on
your Mac?


Brian Willoughby
Sound Consulting


I just did the same test with builtin audio, the recorded audio is also out of sync and this time its about 40 samples too early:

http://wtholliday.org/recording_delay_builtin.jpg

I don't have access to any other devices right now.

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