Re: iMic Pops and Clicks
Re: iMic Pops and Clicks
- Subject: Re: iMic Pops and Clicks
- From: "David A. Gatwood" <email@hidden>
- Date: Thu, 22 Aug 2002 12:31:32 -0700 (PDT)
On Thu, 22 Aug 2002, Uwe Koloska wrote:
>
Sorry, for disturbing the thread -- I am freshly subsribed ;-)
>
>
Now griffin has an answer to this question in the support database:
>
http://www.griffintechnology.com/support/imic/IMIC-019.html
The only way to know for sure is to put an appropriate power filter inline
between the USB port and the iMic and see if the problem goes away. (A
powered hub introduces dozens of other variables, which totally defeats
the purpose of the test.)
I can't and won't attempt to speak for Apple in this regard. I'm an OS
person, not an audio person, so this isn't my area, although my area might
offer some insight into other possible causes.
From my past experience with hard drive electrical noise, it should sound
like a high pitched whine with little chirps. I've never heard hard
drive activity generate anything that remotely resembled a pop. That's
not to say it can't, just that it doesn't fit with what I've experienced
in the past.
IMHO, a more likely explanation is interrupt latency. Adding a USB hub
should result in a device exhibiting slight differences in interrupt
priority, and thus, different interrupt latency characteristics, which
could:
A. prevent a buffer from overflowing (if the latency dropped) or
B. cause the system to allocate a larger buffer at some level, which
would then not overflow (if the latency rose).
That having been said, as mentioned, I'm an OS person, not an audio
person, so I could be completely off here.
Later,
David
---------------------------------------------------------------------
David A. Gatwood email@hidden
Developer Docs Writer email@hidden
Apple Computer email@hidden
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