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Hackintosh to HDTV: Analog audio (RCA) to HDMI+RCA input, Nvidia help!


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Wondering if anyone can help me understand audio "switching" from my Nvidia graphics card out.

After the blood has dried on my forehead from banging my head against a wall to try and get my HDMI audio to work from my Asus P5Q/8400GS to my TV, I've decided on PLAN B to get my HTPC working to my TV. 

My old school TV has one HDMI input under which has RCA inputs for an optional analog audio in. When I connect a Macbook Pro via DVI to HDMI, I can send audio to the RCAs no problem.

When I connect the same DVI to HDMI cable from my 8400 GS, however, I get audio through the RCA while I'm booting up, through the bios post, through the chameleon boot loader, through a good part of the Apple Logo, until the screen flashes to bring up my desktop - at which point, I lose audio to the RCA's. It's at this point that the TV is made to think that it's going to receive audio through the HDMI cable. I'm just at a loss as to what's controlling this "switching" behavior. When I verbose on startup, I seem to get an incomplete verbose through startup because the last thing I see is "SMC successfully initialized", after which I get no verbose for a good minute or two before it flashes into the booted desktop without RCA audio to the TV.

I actually tried booting without the following two Nvidia kexts:

And although I was not able to reach the desktop in the boot process (understandably), I was able to VNC into the machine as well as SSH into its shell, all the while having audio coming through the RCAs.

So my question is: is it something to do with the Nvidia kexts that is sending a signal to the TV to make it think it should be getting audio from it? Or is there some other function in the OS that is causing the TV to "switch" its audio reception from RCA analog to HDMI digital? I currently have no DSDT installed, so it's not that affecting things. Is it some other kext issue? I suppose I could put in my ATI card instead to see if the same result happen, but I thought I would throw this problem out there before I tear up any more machines...

Does anyone have any ideas of how to tackle my problem?

Thanks in advance!

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The TV doesn't let you manually select the source for audio input?


The 8400 GS does not have HDMI sound, you must use a passthrough cable connected to the SPDIF header on your motherboard.


Your on-board audio SPDIF output must be working and set as primary sound output in OS X.

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Thank you Gringo for your response.


Yes, I'm aware of the SPDIF 2-wire output from the board through the 8400. I asked for Toleda's help over at the other place (


And my TV doesn't have a way to manually change the audio of the HDMI input in its settings, so it's getting switched as soon as something loads from the OS side. 


I'm stuck and confused to what's happening.


Thanks for your help though.



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You can change the primary sound output with the audio/midi application in the utilities folder.

If you have no luck in getting the SPDIF output to work, maybe you can switch it back to analog line output from there.


Use console.app to see the part of the boot process that doesn't get displayed during verbose boot.


Anyway if Toleda is helping you, you're in good hands..

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