1.1 Audio out of 2011 MBP

I have been experiencing a strange issue with my MBP. I have a 3rd party mini display port to HDMI adapter allowing me to hook my 2011 13" MBP up to my receiver. My receiver then outputs a direct video passthrough to my HDTV via HDMI so that sound comes out of my system (it is a Sony receiver) and video through my HDTV. This worked fine before in Snow Leopard though, every once in a while, my MBP would output 1.1 audio instead of 2.0 (this is being advertised by my receiver and I can confirm that there isn't any stereo separation). This would normally happen when waking the MBP before turning on my receiver. The solution was to simply restart my MBP and all would be well.

Now, under Lion, my MBP will only output 1.1 audio via HDMI. I purchased a new HDMI adapter from a different company and am still experiencing the same results. I can restart my computer and that doesn't change anything either. Again, no stereo separation whatsoever as the same sound is playing through all channels so I know the audio coming out of my MBP is mono. The funny thing is that I can get 2.0 every blue moon if I hop on my left foot, spin around, and do the Pee Wee Herman dance. This happened after upgrading to Lion and after clean installing Lion. Right now, the only way for me to get true stereo output out of my MBP is to use an analog cable (which defeats the purpose of using HDMI as my HDTV accepts 1080p via VGA as well).

I didn't come across anything in the Sound system preferences either since I cannot adjust the balance for HDMI audio. Has anyone come across something like this or know of a solution?

 

Korn
What TV?
Have you tried running the Mac directly to the TV and from the TV to the receiver to see what happens?

Also just to be clear,are you combining the Optical Digital Audio with the Displayport Video in that Adapter?

OH and.....NEVER do that Dance!

Ed

 

It is a Samsung model but it is not processing the audio. The audio is going straight to my receiver while my TV is handling the video portion only. Even when I turn off my receiver (which will then force both the audio and video to pass through to the TV), my Samsung is also reporting mono audio. The same thing happens if I hook my MBP straight up to my HDTV. My Samsung cannot pass digital audio through so, in order for me to get digital audio playing to my stereo system, I have to go through its receiver.

To clear things up: I am using a mini display port to HDMI adapter for both the audio and video, no digital optical audio at all since my MBP can't output that (at least as far as I know). So far the only thing I can do is either use an analog cable going from my MBP to my receiver or have my HDTV output analog audio (since it can't digitally passthrough audio from an HDMI source) to my receiver. The later is still mono though since my MBP is not correctly sending stereo audio out of the Thunderbolt port.

 

I think your MBP will output Optical audio from the same mini jack as the Analog.
It just needs a Toslink-Mini Jack adapter to work.

I was just trying to see if the HDMI decoding in the TV might be more capable than the one in the Receiver for some reason.

It is odd that this all started after going to Lion?

I will try over the weekend to experiment with this myself.
I have an 11" Air with Lion and other MBP's with SL.

I will let you know what I discover.

Ed

 

Ah. Well, I don't have a mini optical audio adapter so I would have to buy one (and order it). I had the issue in SL once in a while but a reboot would make my MBP output stereo audio. That fix just doesn't work in Lion and I haven't figured out what to do. Thanks for trying, I will let you know if I find a solution.

I think Apple changed some audio output aspects of Lion as VLC can no longer output Dolby Digital or DTS audio to my receiver via HDMI when, under SL, it could do that without issues. My MBP outputs stereo audio in Windows and even DTS/Dolby Digital through HDMI so it isn't a hardware issue. Given that I was experiencing this in SL and now in Lion, I am going to say it is a Mac OS bug that either people aren't noticing or they aren't coming across it.

Edit: I found a solution to get 2.0 audio out of my MBP's mini display port but something is fishy. I found that if I put my MBP to sleep, turn off my receiver, turn off my HDTV, turn my TV back on, turn my receiver back on, and wake MBP that it will output stereo audio. However, during this period, my HDTV will display a black image for 1 second once every ~15 seconds and my MBP will keep doing this for about 45 seconds until it starts outputting 1.1 audio again and then the screen flickering will stop. I also took my MBP to my HP LCD HDTV and it too is reporting mono audio (since, like my Samsung, it can't handle more than two channels unless it is an over-the-air broadcast so that extra .1 is lost).

 

That is interesting.

It sounds like the HDMI key exchange is somehow not working with your adapter in Lion but mostly does in SL?

The way HDMI negotiates the license key for copy protection before decoding is the tricky part of HDMI compatability.

Each version of the HDMI standard "Tightens Up" the adherence to the standards and thus kills devices that have worked before.
I bet that in Lion the HDMI calls are not supported by your adapter.

Welcome to my world.

They think this helps us too so each version of advanced performance causes problems but evidently the backwards compatability is not that important as long as new models can be sold.

I wonder if there is a way to report this to Apple? I have not seen anything about it yet.
I mainly install a System though where they purchase a license key for each device in a system so once initialized they don't need to negotiate again thus giving broadcast quality fast switching.

I don't know of any consumer gear that does this.

 

Also have you tried this?
Evidently it fixes several different strange audio symptoms caused by the upgrade?

No HDMI Sound Under OS X Lion Using A Mini DisplayPort or Thunderbolt Adapter? There’s An Easy Fix For That [How-To] | Cult of Mac

 

I thought it was the adapter as well but I purchased a new one from a completely different company (and it is a completely different cable) and it is doing the same thing. I came across that fix but my MBP still only pushes 1.1 audio, it didn't do anything to help it send out actual stereo audio via HDMI.

 

I am going to shamefully bump my post to see if anyone else is experiencing this. I thought the issue went away with Apple updating OS X to 10.1 but it came back last night. I was actually surfing the web when my HDTV went black for a second and kicked back on. I then looked down at my receiver and it was reporting 1.1 audio. It has been doing that ever since despite me trying a third cable and restarting my MBP about a dozen times. The strange thing is that when my MBP outputs 2.0 audio, it only does so when there is audio actually playing. Until then, my receiver isn't picking up any audio. So I can open up iTunes and my receiver won't report any audio coming in. I would start playing a song and then it would report receiving 2.0 audio. Whenever I get 1.1 audio, it is always receiving that whether or not there is something playing. Again, it is true 1.1 audio as it is only coming out of my center channel and subwoffer instead of my left and right speakers (so I can't matrix it out to my other speakers and subwoofer).

I have gone through three mini displayport to HDMI adapters and they are all producing the same results. I will clean install Lion again this weekend since I am getting an SSD for my MBP but I doubt that will fix anything especially since Lion has been a lot more problematic than SL in this regard.

Edit: And just like that, my MBP is outputting 2.0 audio again. This is really ticking me off especially since the problem is so random and nothing seems to fix it.