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Re: Complex Play Thru app fails
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Re: Complex Play Thru app fails


  • Subject: Re: Complex Play Thru app fails
  • From: Brian Willoughby <email@hidden>
  • Date: Mon, 31 Jan 2005 18:01:46 -0800

[  On Jan 31, 2005, at 10:40 AM, Doug Wyatt wrote:
[  > Are your SoundSticks connected via a USB hub, including one in the
[  > back of a monitor or a keyboard?
[  >
[  > Recently I came across a Knowledge Base article that said (if I
[  > remember it correctly) that that is not a reliable configuration; they
[  > should be connected directly to one of the CPU's USB ports.
[
[  From: Shawn Erickson <email@hidden>
[  I have had them attached to either the ports on the tower or on the
[  back of the monitor at different times in the past. It does happen more
[  often when attached to a port other then one on the tower but I did
[  have it happen when connected to the tower at least a few times (in 3+
[  years of use).

Audio problems can happen even when connecting directly to the CPU.  This is
true at least on my Dual 800 QuickSilver.

I noticed a problem with my Emagic emi2|6 and eventually tracked it down to
which USB port I used on the back.  This CPU has a stacked USB port with 2
connectors.  The one closest to the motherboard performs poorly with audio
under very rare situations, and I initially favored using it because it is
labelled "1."  I am now in the habit of plugging critical audio into USB "2"
and I have never had audio problems using that port.

I seem to recall that the Apple System Profiler showed a hierarchy of USB bus
and USB hubs that changed according to where I plugged in my audio card.

I just checked now as I composed this message, and the Apple seems to
dynamically move the hub in my Cinema Display between USB Bus 0 and USB Bus 1
according to which one is free.  But, if you're using both ports, the audio
sometimes ends up sharing a Bus with the Monitor Hub (although it appears to be
upstream of the Hub, at least), and which port loses this contest seems almost
random.  I guess not many folks have multiple USB Audio Devices, or we would
hear about this more often.

You might want to check Apple System Profiler on your machine, too.  I think
you have to plug something into each port before the graph will show how things
get juggled around.  Apple System Profiler doesn't have an update that I could
find, so make sure to quit and restart each time you plug or unplug to see the
new USB arrangement.

Brian Willoughby
Sound Consulting
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References: 
 >Complex Play Thru app fails (From: Rolf Nilsson <email@hidden>)
 >Re: Complex Play Thru app fails (From: Shawn Erickson <email@hidden>)
 >Re: Complex Play Thru app fails (From: Doug Wyatt <email@hidden>)
 >Re: Complex Play Thru app fails (From: Shawn Erickson <email@hidden>)

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