[AG-TECH] External Audio interface with MacPro

Fred Dech fdech at uchicago.edu
Fri Sep 28 11:27:01 CDT 2007


hi.
yesterday i picked up a creative labs usb soundblaster live! 24-bit external.
i picked this up because i've never been able to get reliably, decent AG audio
running rat on either a laptop or desktop intel mac and i was hoping that
this device would solve the problems.

before the 10AM CDT ANL testing session, i plugged the soundblaster USB
into the mac and connected a line out and line in between the soundblaster
and a xap400.   the audio quality wasn't outstanding, but there was no
garbling of the audio signal as is usually the case in my experience when
using direct mac line in and line out.

what we did experience, though, on both the mac RAT and other remote AG
clients in the Venue was lack of synchronization between video and audio.
the audio i was sending lagged behind the video i was sending on remote
clients enough to where Tom outright refused to look at me...  no joke!
at my end, everyone else's audio lagged behind their video by about 3/4 second.
not something i'd want to expose our potential user-base to.
btw, i'm running a recent (downloaded this week) AG 3.1.0b1 for intel os-X
install from the accessgrid software page.

anyone have a theory on why the lagging, out-of-sync-with-vic rat audio?
that is not something i was expecting from use of the external
device.  i assumed/hoped that by using an external device, the lack of
synchronization issues with rat on os-x would disappear.  it got worse.  in
my experience with rat on intel mac, the audio on the mac side (what i
hear) is out of sync, but the audio on the receiving client's side (what
everyone else hears) while not very intelligible, is in sync with the video.
using this audio box causes both sides to be out of sync.

thanks.

--fred




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