Have any of you heard of this before?
I'm using an Alesis io26 firewire interface with a 2009 Macbook Pro and whenever my external monitor is plugged in to the display port via a HDMI adapter I hear this terrible noise. The closest comparison I can think of is artifacts from a really low bit rate MP3, like an audiobook from 1997 or something. Unplugging the Macbook charger makes the noise louder/ worse. When the monitor is unplugged it's fine. My USB audio interfaces have no such problems.
I've tried it with different power outlets and with a different HDMI adapter/ cable, I've tried unplugging peripherals. No luck.
Switching my laptop for my brother's almost identical MBP solves the problem which is kinda frustrating as my laptop is 3 months out of warranty and if my previous Apple repair experiences are anything to go by this will be a logic board replacement situation.
The weird thing is that if I turn down the volume of my monitors and compensate by raising it on the interface the noise becomes quiet enough to be ignored in general use. Confusing.
I guess this is more of a moan or a curious attempt to understand what's going on here rather than a shot at actually fixing it, but maybe someone here has experienced the same thing...
Macbook display port causing noise on firewire interface
Not the same thing, but something equally as odd; my mobile phone would completely drop its voice/text signal (but not it's data signal) when I got a new PC laptop (not Macbook), and hooked up my DVI display with a DisplayPort-DVI cord. When I plugged anything that was plugged into the laptop in to anything else (power cord to the printer, USB to my phone), my DisplayPort would shut down until I unplugged it and plugged it back in.
I ended up buying a better-quality DP to DVI adapter, and the problems went away. Are the two DP-HDMI adapters that you are using the same brand/quality? If so, you could try picking one up that's completely different, and seeing what happens.
Good luck!
I ended up buying a better-quality DP to DVI adapter, and the problems went away. Are the two DP-HDMI adapters that you are using the same brand/quality? If so, you could try picking one up that's completely different, and seeing what happens.
Good luck!
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- IanWalker
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Okay, so I used to have a similar issue with my G5 Powermac, and I found this:
http://hints.macworld.com/article.php?s ... 0105729848
and several other threads elsewhere about it.
CHUD Tools allow you to diable processor nap, which is what was causing it for me.
Worth trying. I don't have DevTools installed now, but you can nab XCode from the App Store in Lion or newer. Its a 1.6GB download, so I'm downloading it right now, but it'll be a few minutes before I can check if that feature is still there
http://hints.macworld.com/article.php?s ... 0105729848
and several other threads elsewhere about it.
CHUD Tools allow you to diable processor nap, which is what was causing it for me.
Worth trying. I don't have DevTools installed now, but you can nab XCode from the App Store in Lion or newer. Its a 1.6GB download, so I'm downloading it right now, but it'll be a few minutes before I can check if that feature is still there
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Ian!
http://michigansoundservices.com/
Drivar dohaeris. Drivar morghulis. (All drives must serve. All drives must die. Basically, back up your data.)
Ian!
http://michigansoundservices.com/
Drivar dohaeris. Drivar morghulis. (All drives must serve. All drives must die. Basically, back up your data.)
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