EXS 24 Logic Sampler Users Group

your inside (insight?) is very apreciated here. thanks a lot.
cheers,
u.

(ps, that kind of sound drove me crazy with the titanium powerbook. thats
why i returned it. apple was not able to admit it. i was the onlyone (they
say) to complain at that time. but EVERY titanium i had a chance to test
made that kind of sounds... )

> I assume you're talking about the audio problem with the G5.  This problem is
> pretty 
> common actually.  I've heard that there are people that don't have it... but I
> have no idea 
> how wide spread this problem actually is.  However a huge number of pro audio
> people 
> are all complaining about the same problem on the official Apple Disscusion
> board.  
> Anyway, here's the break down.
> 
> There is a really weird high pitched digital screetching noise.  The noise
> sounds like the 
> volume is related to CPU activity.  It's loudest when the you switch windows
> with Expose or 
> scroll windows.  And kind of chirps at about 1Hz when the CPU is idle.
> 
> This noise also leaks through to the audio outs.  And the really weird thing
> is that it even 
> leaks to audio outs of fire wire audio devices.  I don't know of this
> happening first hand
> since I don't have a firewire audio device, but a lot of people with MOTU
> 828's and Digi 
> 001's say it does.  Another problem is that the noise leaks to monitors that
> are grounded 
> to the same power source.  I havent experienced this either, since I live in
> Japan and here 
> there is no third prong on the power cord for the ground (just like a little
> wire... but since
> the only ground source in my apartment is in the other room, I don't have it
> hooked up).  
> So basically none of my set up is grounded.
> 
> As to what's causing the noise, most people say that it's some kind of ground
> loop caused 
> by the power supply.  Apple is already on Rev. E for power supplies just
> because of this 
> problem.  Its not totally fixed yet, but I've heard that Rev. E is an
> improvement.  Apple is
> being really shady about the problem though.  They already closed the biggest
> message 
> stream on the official Disscusions page, and most AppleCare people often deny
> people's 
> complaints.
> 
> There are some kind of band aid fixes though.  One is a software solution
> called CHUD.  
> CHUD is a bunch of tools for developers made by Apple.  Its not included with
> OS X but 
> you can download it from the Apple Ftp pretty easily.  Anyway there is a
> feature where you
> can edit CPU settings.  If you disable something called NAP (which appears to
> be some 
> kind of idle process) it cuts down on the noise a lot.  But it doesn't remove
> the noise 
> leakage from the audio outs.  For that, you need a device called a Ground Loop
> Isolator.  
> These can be picked up at any Radio Shack and sell for like $12.  I had a
> friend mail me 
> one from Seattle (since I couldnt find any here).  For fire wire audio outs
> I've heard this 
> works too, but I think you would need one for each out.  So like for the MOTU
> 828 you'd 
> need 4 Ground Loop Isolators (they come in a  stereo pair).
> 
> So thats the big problem.  I have one of the first Dual G5's in Japan.
> Acutally this is my
> second.  The first one I had a huge problem with the fans and had to be
> returned.