Macbook PRO HDMI sound stopped working

Hi everyone,
I'm new here and created a profile because I could not find the answer to my question.

The problem is:
I have a 17" i7 MBP (Purchased from Apple in Sept 10) I purchased the display port to HDMI from Apple as well ($40) the one that give image and sound.
I used to be able to connect my MBP to my receiver and send image and sound out from the receiver and TV but just recently, I've replaced my TV with a projector. Now I only get an image but no sound..? I tried connecting my friends MBP 13" and same problem.
I already looked up the specs and it shows the HDMI port in the computer profile thing. I also went to the system preference > sound > audio output and where HDMI "used" to show, now I only see the built in speaker option.

The Setup (Before and Now)
I have a MBP 17" Sept 2010
Samsung HT-AS730 Receiver with 3 HDMI in and 1 HDMI out (Before & Now)
Samsung TV 40" (Before)
Optoma HD200x projector (Now)
PS3 (Before & Now)

The Optoma projector is connected the the HDMI out from the receiver. The PS3 is connected into HDMI1 in (Didn't change) The macbook is connected to the HDMI2 in (Didn't change) HDMI3 in is not in used.

I'm not sure if this is just a coincidence that I can no longer select HDMI sound out after I changed the TV to a projector or if the switch has somehow messed up something? I don't get it though since I didn't think changing TV can affect the sound output? Or can it?
Has anyone ever had this problem and how to fix it?
I tried switching the macbook HDMI to the input 1 and same issue, no sound.
But it was working fine on the samsung.
Since the HDMI is going to the receiver, and technically the sound should be only going into the receiver (The projector doesn't have built in speaker) I'm not sure if the problem is related to the MBP or the receiver, or the tv :-S
I didn't change any settings on the receiver.

Hopefully someone can help.

Without getting into too much detail, I would guess that the Optoma projector does not accept sound in through its HDMI port. Your model MacBook Pro definitely outputs sound and video from the MDP to HDMI which is why it works on the TV. The TV HDMI port accepts both video and sound as does the Samsung receiver.

You're probably going to have to use a separate sound output to the receiver and then to the speakers in order for it to work. I've used more sophisticated and expensive projectors than the Optoma and they work the same way, no sound in. We always send the sound to a separate amp and speakers.

If you used the same adapter/cable on your friends MBP, and it is a model which will indeed output audio via the mdp - not all of them will - my first suspicion would be the adapter.

I would think you had been selecting the receiver as the output in Sound preferences on your MBP, not the TV previously?

Have not run into this scenario personally (yet), so can only advise to experiment by connecting the TV back up to it and see what happens.

You might try a PRAM reset - although, don't think this will do it, since you've tested another MBP.

Next step is probably going to be taking it into an Apple store, with your adapter/cable in hand and testing it there where you'll have access to another adapter & cable.

Thanks for the help everyone.
To help with the replies, I wanted to add, the sound is intended to come out of the 5.1 speakers connected to the receiver and not the projector.
As for the adapter, I will test it tonight. It would be very co-incidental that the adapter get damaged on the audio part at the same time as I replaced the tv to the projector. I'll plug a HDMI to the old tv directly and if sound comes out of the tv then that would mean the adapter is fine.
I guess I'm just new to HDMI technology and I know it's more advance than standard analog. Can a projector cause the receiver to be confused and block the audio to pass from the mbp to the receiver?
Also, from the receiver settings, I used to have the receiver and the tv connected together via optical for the anynet + freature (Something samsung has to pair the device together)
Yesterday I turned off the anynet freature from the receiver (The only thing I could think that could confuse the system) but I still got no sound.

I think that maybe the problem has something to do with the communication between device. I tried a DVD in the PS3 and I get audio from the receiver 5.1 speakers and video out of the projector. It's only when I connect my MBP that I don't get audio and no option to choose HDMI on the Sys Pref > audio

Bobtomay > What is a PRAM reset? How do I go about doing that?

Well.... I got home for lunch and did more test. Long story short now it's working. I'm not sure how I did it though and why it works now.

I tested the adapter on the TV and it worked. Then I tried the reveiver & projector and still nothing. I unplugged the HDMI out while the projector, receiver and MBP were connected and running. This resulted in the screen to go blank but the MBP stayed at 1080P. Then I plugged back the HDMI in the receiver and when the picture came back on the screen, it came back to 720P and I looked in the audio settings and HDMI came up (with the name Samsung AVG or something like that)
I went in the display settings and changed it back to 1080P 60hz and the audio stayed on, I then moved on to calibrating the image and saved the settings. What's funny though is that it keeps showing Samsung AVG or AVR I can't remember, but basically it's almost like the computer or receiver or something, is telling the computer that the TV is connected.
If the problem doesn't persist I'll just leave it be, but if this continues, I wonder if the confusion comes from my receiver or from my macbook...?

Well, today I plugged the MBP back to the receiver and again, no sound.... I tried different things which I remembered from before but no cigars.. I don't get it, I don't know what to do....??
This is seriously getting on my nerves, This whole setup was done specifically for the macbook pro to play on my projector

okay, just to add more, I remembered last time by unplugging the HDMI out to the projector it made the HDMI sound come out on the preference> sound section
Well I tried this today and it didn't work but something interesting is, everytime I unplug the HDMI out to the projector, my MBP goes automatically to 720P resolution and the HDMI samsung AVR option comes up in the sound, then when I plug the HDMI out again, the MBP stays at 720P but the HDMI sound option goes away on the MBP...
Could it be that the optoma HD200x projector is messing up the audio coming from the MBP to the receiver?
I don't undertand this. I'm getting a headache!

My guess would be you have the Anynet+ mode enabled on the receiver.
This is the function that allowed you to select where you wanted to listen to audio via HDMI - on the receiver or your Samsung TV.
Possibly, the last time the TV was connected you had it set for audio through the TV - which is done on the TV, not on the receiver.

To turn it off:

I had Anynet turned off already. And just to make sure, I brough the tv back to my setup, connected everything back to the tv, and then turned off anynet and then unplugged everything... Still no sound
It almost feels like some sort of conflict, everytime I connect the HDMI out to the projector, the HDMI sound on my MBP dissapear, then when I unplug the HDMI out to the projector, the HDMI samsung AVR sound option in preference comes back up.

I'm not sure if anyone may have some idea what could cause this...?
Oh and the sound on the receiver is set to AVR and not TV.

The issue has to be at the receiver. Make sure you have also turned off Anynet in the AVR menu. I'll do a little more digging in the manual and see what else I can find.

When you re-connected the TV this time, did the option also disappear from the MBP audio preferences?

The only two things I see you've already done - Anynet is off and HDMI Audio is set to AVR. I'm stumped.

Normally, I'd suggest resetting the PRAM on your Mac, but that really doesn't apply in this scenario with it working until you plug in the projector.

Think I'd be calling / emailing Samsung tech support.
Keep it short and sweet.

When connecting my computer to the HT-AS730 via HDMI - audio works via the connected speakers.
As soon as I plug in HDMI between the receiver and projector - audio quits.
Disconnect the HDMI out - audio works again.

HDMI Audio is set to AVR.
Anynet is turned Off.

Click to expand...

You might head to the AVS forums and see if someone there has heard of the issue also.

(Since you have had it work at least once - the way you've described it, I'd try that again - try changing up the resolution, wait a few... maybe try unplug and replug at the diff resolution. Shouldn't have to go through a bunch of tricks, but...)