iMac surround sound

Hello all

I need help. I've looked everywhere and can't get this to work. I have a 21" iMac that I purchased earlier this spring. I have a new Onkyo receiver that has optical inputs for digital sound. I have a 6ft Toslink to Mini Toslink Cable plugged into the headphone jack on the back of my iMac and it goes into the optical input in the back of my receiver. The red light comes on on the cable when I plug it into the iMac which tells me that the digital sound is working.

However, when I play anything I only get 2 channel stereo. iTunes HD downloaded movies, DVD movies, ripped DVD movies, everything. Only 2 channel.

I have downloaded Perian and have tried it with Dolby Pro Logic, Dolby Pro Logic II and Multi-Channel Output. I've gone under my Audio Devices in Utilities and changed the format to 48000.0 hz. I've also tried 2 channel 24bit and 2 channel 16bit.

No matter what I do I still ONLY get 2 channel output. This is very frustrating. This is about the only thing that has given me problems since switching from a PC. I had no problem getting 5.1 surround on my WIN7 PC. I would think that it would be easy on the iMac (everything else has been easy).

My receiver has 5 HDMI inputs and 2 Optical inputs and has NO problems spitting out 5.1 (can go up to 7.1, but I don't have anything that has that yet) surround sound from our DVD player and Cable TV box.

What is going on here? Am I doing anything wrong? or should I head to the Apple store and see what they say?

I'm at a complete loss.

There is a laundry list of reasons why it would not work with ripped movies, depending on the container. But with DVDs, it should be fairly simple. Open the DVD player application and check to see what is the default handling for audio under preferences > disk setup. Make sure it is set to send audio directly to the digital out and not to system sound output.

You should be getting 5.1 from DVDs with this method.

There is also a laundry list of options you could have set up on the Onkyo.

The key is that you will only get 2 channel from all 2 channel souces, such as all of your music, and it will output 5.1 only from 5.1 sources. There is no ProLogic built into the Mac, so to obtain 5.1 speaker output from stereo sources you'll have to use the ProLogic on the Onkyo.

If the Pro Logic (II) is not outputting 5.1 even from a stereo source, I'd be looking at some setting on the Onkyo. I also use Onkyo on one of my setups and have not experienced the issue.

Can experiment some, but def won't have the time to do so until the weekend.

I figured it out. Its the receiver.

Here is my set up. We have an older Sony HDTV with only 1 HDMI input. Up until this past spring I was using an HDMI switch to run multiple HD devises (ie: cable TV, DVD player, Computer).

One of the reasons I bought this particular Onkyo, besides the great sound quality, is because it has 5 HDMI inputs and I can use it as the switch instead. (My old receive was purchased in 1993 and I was ready for an upgrade) So everything goes into the receiver then to the TV. This includes the iMac. Up until recently it wasn't really a problem. I've now started getting more stuff on iTunes and have been ripping more movies. (I think I'm going to get an Apple TV for x-mas to make using movies on the computer even easier). I realized when watching Iron Man that I was only getting sound from 2 speakers. Frustrating.

Earlier today it occurred to me that maybe the HDMI input from the iMac was giving the receiver the wrong info, even though I have the sound going to the optical. As we know on the iMac, no sound is carried from the computer via the mini-display out. So to get sound to the receive we use the optical output. Well right now as the receiver goes, it seems to be getting wrong info. Its getting the sound from the optical, but is only sending it out as 2 channel stereo and I'm also getting sound directly from the TV speakers. If I shut the TV off and run the video picture on just the iMac, the HDMI part of the receiver shuts down and switches itself to the optical, thus giving me the full 5.1 surround sound.

Now I just have to figure out how to override the receiver to use the optical input as sound and cancel out the HDMI. I don't know if this is possible. I've gone through the menu on the receiver, but may have to break out the owners manual to see how to do that. If it can do that.

Ok, now I'm with you. My Onkyo is probably a model or 2 older than yours as I only have 3 HDMI in ports on it. I don't think there is a way on the receiver to tell it to use a separate audio input with HDMI the way you can on many TVs, or at least I never did figure it out - and I did spend some time reading the manual.

Ultimately with my Mac, I run the HDMI straight to the TV and the optical to the receiver.

This was just another of those niggling things that caused me to decide on building a Win box for HTPC use.

I've tried a few things on the receiver that I thought might split the sound off, but nope. Nothing.

I think what I'm going to do is have someone in my family get me the Apple TV. What I'd be using it for mostly is to watch movies from the computer. I'll just rip the movies the kids watch the most to iTunes and use the Apple TV to watch them on the TV. The kids also like to listen to music and dance around and the Apple TV can play that from iTunes as well. For $99 it serves its purpose just about perfectly. I'd rather hook up a Mac Mini as a Home Theater PC, but can't justify the $700 for that right now.

Using the Apple TV to stream from my iMac would solve my HDMI input issue without having to go back to the HDMI switch. Also I finally got everyone in the house used to the "new" setup using the receiver as the main switch for everything. Last thing I need to do its switch it around again and confuse everyone.

Thanks for everyone's understanding and willingness to help. Much appreciated.

I built my htpc from an upgraded 1.5ghz solo mini. 2gb of ram and a 2.0 C2D processor brought the total price to about $300. I use a DVI-HDMI cable and optical digital out to my receiver. I have also done the esata mini mod and have it connected to a ProBox with 4 1.5gb hard drives. Plenty of movie storage. The 2.0 handles 1080p just fine. Grab yourself an xbox 360 usb wireless adaptor and a SNES, N64, or SEGA emulator and you can keep those kids busy for hours and hours!!!!

That may not be a bad idea, to look for an older used Mac Mini. I really like the idea of using that for the HTPC. I read a blog from someone that is really into the HTPC and uses an older Mac Mini and also found a 500GB external hard drive that is pretty much the exact dimensions of the Mac Mini. My iMac has a 1TB hard drive, but ripping movies, even only at about 1GB each fills it up quickly (along with my RAW files from my digital camera).

What does anyone think the best place to find a used Mac Mini would be and what should I look for as a minimum for performance. I would solely use it for the Home Theater along with an external hard drive so the hard drive on it doesn't need to be big. I would be limited in price to probable $250 maybe if I hide it well enough, $300.

For the kids, we're going to get a Wii for them for x-mas. Have a playstation 2 downstairs for occasional use.

Thanks for all the info.

You can find used minis on craigslist and eBay pretty often. If you are comfortable taking it apart and swapping out components, you can start with the lowest priced intel mini (1.5ghz solo core usually around $225 on eBay) and pick yourself up a t7200 2.0ghz processor (around $60). This is the lowest speed CPU that I would recommend. There are t2500's out there that run at 2.0ghz and cost less, but don't be tempted, the extra 2mb of cache is necessary for smooth HD video. Maxing out the ram (2gb) will run you another $40. So you are looking around $325 for the computer itself.

If you don't want to do the upgrades yourself, then the 2nd generation 2.0ghz minis on eBay run about $450-$500 depending on memory and hard drive size.

Most of these units come with a small hard drive installed. I think the best option is to stick with the small internal drive for the OS and think externally for mass storage. Because these first generation intels only have firewire 400 ports, usb is going to be your best bet for data transfer. It will work fine for HD video. I did upgrade my mini to esata, but that was because I sometimes have HD video playing locally and also streaming to another computer in the house simultaneously. In these instances, USB just couldn't keep up.

I think this setup is worth the extra cash it takes over the Apple TV. I am not limited to any certain codec for my files, and Plex makes finding online content almost effortless (these are just a couple reasons...there are many more things that are possible on the mini that the Apple tv just can't do). My mini has basically turned into a combo htpc/file server for the other 4 macs in the house. And it holds up great and keeps trucking right on along.

Hope that helps. I guess I may be "mini biased".

Thank you very much for the info. I think I'm going to hold off on the Mini for the time being. i need to save up for a new lens for my camera set up. For now the Apple TV will do what I need and its an inexpensive x-mas gift.

The Mini is in my long term plans as a Home Theater PC set up. I think, for me, waiting a bit will be better. I can get the HDMI output on the newest model and in a few years they will be available cheeper used. Who knows what the next upgrade will be.

Thanks again for the info.

No trouble. Everyone has different needs and I hope the iTV fits yours. Enjoy!!