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I know Super User is not a 'tech support' forum, so I will try to make it short: my computer's sound does not work anymore. I have asked for support on the Apple board but I feel a bit on my own. To summarize, the Sound Panel of my iMac does not display any outgoing channel (headphones or internal speakers). It does not work on Windows either.

Contrary to what it may seem, I have the feeling that it is not a hardware issue (and that GarageBand is somehow interfering). If you have an idea to solve the problem, please share.

Making it work again is a lost cause without sending it back to Apple, so the question I'm asking is:

What is the best workaround (cheap Firewire sound card?) for getting my sound back?


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You are right with the fact that SU is not a 'forum', it is a Question/Answer site. But it is for 'tech support'. I.e: Computer hardware/software questions. There is more information about what you can/can't ask on the site in the FAQ. – Wuffers Dec 26 '10 at 17:51
up vote 1 down vote accepted

Hmm... I'm going to assume that means you don't see "Intel High Definition Audio" in System Profiler at all, either. If you do, you might need to poke around with your output jack a little bit since it's possible a piece of dust got in there and activated the optical out. I've also seen recent iMacs that lose their sound output until some headphones are plugged in and out—weird stuff like that.

If you don't see the audio interface in System Profiler, you could try a PRAM reset or SMC controller reset and see if that helps. Though, if your startup noise is nonexistent, I'd say its highly likely that something hardware-based is broken. Maybe you have an older iMac, but nowadays the startup noise is used almost as a diagnostic by code on the motherboard itself—it'll even sound if you don't have a hard drive installed, IIRC.

Anyway, if none of that works, then yeah, I'd go digging for an external interface. Firewire is actually going to be a bit more expensive than USB, generally. The first thing that comes to mind is Griffin Technology's iMic, which you should be able to pick up for about $30.

If you want to spice it up a bit, check out these USB interfaces from Behringer—all have a headphone minijack, and you can choose between an optical out or a grounding pole for record player input:


They're about the same build quality as the iMic, but they're marketed towards audio professionals so they're at least touted as professional-grade. Personally, I use a UCA200 (the minimum feature set kind they throw in with all their mixers) with my MacBook Pro to interface with an external mixer, and I can say the audio quality is actually much better than the built-in Intel HDA. They may have changed stuff since 2007, but I know that card has all sorts of noise and artifacts you can hear if you're listening with good headphones. The Behringer is perfectly silent by contrast.

EDIT-How to reset PRAM and SMC

The PRAM is pretty simple--restart the computer while holding down command-option-p-r until you hear a second chime... well, how about that. Though, you can continue holding down command-option-p-r indefinitely; the computer will just keep cycling until you let them go. If this is successful, you'll hear a chime after the first cycling, anyhow. Otherwise, just let it boot after you're sure it's cycled at least once.

If that doesn't work, try the System Management Controller: shut down the computer and unplug everything, then hold down the power button for at least 5 seconds, and release. Then plug back in and see if that helped.

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I do see the HDA device. I have tried plugging in and out my headphones in the output jack ten times in a row (read this somewhere…). It did nothing. – Warren Seine Dec 26 '10 at 23:40
Any luck with a PRAM reset? – NReilingh Dec 26 '10 at 23:52
Already tried, no effect. – Warren Seine Dec 28 '10 at 12:14
Just so you know, I bought a Line6 Pod Studio GX, which is basically the same as the USB interfaces you mentioned. It's more guitar-oriented though (and more expensive), and I'm pretty happy with it. – Warren Seine Jan 2 '11 at 14:09

When you reboot, do you hear the 'boonnnnng' startup sound? Nothing else would be running at that point. If you hear it then, it's not a hardware issue. At that point you should know whether you're chasing a hardware failure or software interference.

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I had disabled it so I was not used to hear it anyway. But now that I have re-enabled it (and that I still do not hear it), I am getting a bit worried. Thanks for the key. – Warren Seine Dec 26 '10 at 20:26

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