mini displayport to hdmi audio not working

I recently bought a mini displayport to hdmi adapter with audio support. I connected this and a hdmi cable between my macbook pro(purchased feb 2010) and tv. The video worked fine but the audio was still playing through my macbook. I went into system pref>sound>output and the only option available was the internal speakers. The tv speakers had not been detected. I tried reconnecting, rebooting, and other tvs. Any advice as to why the audio won't play and why the laptop won't recognize that other speaker options are available? All reviews on this adapter said that as long as the macbook was purchased in 2010 then the audio would work.

I could be wrong but I think that the MacBook prior to April 2010 didn't have audio through the mdp. I'm sure people with more knowledge than me will pipe up but u may want to start there And google it.

The MBP line did not support audio via the mdp until the mid-April 2010 release.

You will need to use a separate audio cable appropriate for your TV.

Thanks. Is there any way to transmit audio & video all through one cord or is the best I can do maybe a adapter that splits between displayport and audio/usb?

Two cords one to your mdp one to your head phones jack. It's how I do it and works rather well.

There are a couple of adapters out there that will combine the video and audio so that you can use just the HDMI cable to the TV. But, they're about $40. I'd just stick with what you've already got. You can pick up whichever audio cable you need for under $10, maybe under $5.

Combine optical
Use a USB port

I use the 2 cables also with my Mac, but then I only run the video to the TV and run the audio to the surround system. I don't think the audio on a TV of mine has been used for at least 20-25 years.

I didn't know u could get sound out of a USB port. Anyone using this? Does it work well?

schweb uses one of them, but I forget which one.

You can check the reviews tab there at monoprice.

I looked up some cables and Kanex has a few options as well. I don't know how well they work but I don't really have any good options of going straight from laptop to speakers so playing through audio through hdmi still might be the best option

To get audio to the TV, pull out the owner's manual or look it up on line.

Read post 3 here, so you'll know what audio cable you need.

Should be either a mini-plug at both ends or a mini-plug to RCA for practically all TVs. You can get either one of those for about $3 at Amazon or probly $10 at any local electronics store.

There are some of the first couple of years models HDTVs that did not allow for separate audio with HDMI.

Actually, there is a new solution for older Macbook.

I bought a USB　to HDMI adaper from Cable Matters.
It works great with my old Mac and transfers both audio and video.
It also works on my Thinkpad.

It's a pretty good deal considering it can transfer any computer to tv.