5.1 Surround Sound Speakers

I'm guessing that like with AV Receivers, you have to feed it a true AC3 Dolby Digital/DTS 5.1 signal to get discreet 5.1 performance from the speaker system, otherwise it's using ProLogic or the like to virtualize the stereo signal coming in. If you play a DVD on your computer, then you can probably output the 5.1 DD/DTS track from the optical/coax and into the Logitech unit...you may have to make sure you have that selected fro the DVD's setup menu.

Otherwise, with MP3's/music and a lot of other media, you're always outputting a stereo signal, and the Logitech unit is using internal DSP to make a virtual surround field, like with ProLogic on an AV receiver.

There is another method for 5.1 -
I run firewire out to a Focusrite Saphire which is running 5 professional monitors (M-Audio) and a powered sub-woofer. The saphire has a complete control panel to run surround system.

Its overkill for most people - your computer speakers are fine, but if you want to edit sound, you need studio monitors.

Help... I have almost the same setup, but for the life of me I can't seem to get the optical audio out to play through the Logitech Z-5500.

It sounds surprisingly good just through line-out, but i was really hoping for the optical digital output for 5.1.

I've tried sound preferences, midi settings and it seems to keep defaulting to stereo output (no sound) instead of the digital encoding output.

Any chance you can post your exact settings?

Many thanks in advance.

Works fine over here.

Note that there is no 5.1 support through Mac OS X or ANY sort of game with the 5500's, even with any other sort of optical setup.

Optical audio assumes you have a DTS or Dolby Digital signal to work with, which means you need to encode data on the fly in order to get 5.1 from these speakers.

Ergo, there are no applications (that I'm aware of) that support this- save for the DVD Player, but that's passthrough audio- since the DVD already has a DTS/Dolby soundtrack on it. No games or iTunes will be able to play audio back in full 5.1 sound.

Bottom line is that you'll get 2.1 sound from the 5500's, and 5.1 when watching a DVD. That's about all there is to using the 5500's with any sort of Macintosh, unfortunately.

-SC

Errr..

I might add that the 5500's automatically switch into DTS/Dolby 5.1 mode when they detect the appropriete optical signal. You can't select a 5.1 input until that happens- it will let you play Stereo/Stereo x2/etc, but there really isn't anything else to set on the 5500's end, aside from telling your Mac Pro to output through the digital port.

-SC

As previous posters said: The Mac Pro has no 5.1 encoder so you can only get 5.1 audio on the optical port if it's pre-encoded (so mainly the DVD player, theoretically Quicktime can do it too).

You can get a $40 piece of equipment called a Griffin Firewave which will add analog 5.1 to your Mac Pro.

Mac Pro Mac OS X (10.4.9) ATI X1900XT - 5GB

Thanks all for the replies... this half confirms what I was expecting from the specs, but was confused by postings from other users on a couple different forums.

One more question about what you had just said...

"You can't select a 5.1 input until that happens- it will let you play Stereo/Stereo x2/etc..."

Specifically this is via line-out or optical out? Even using stereo output over optical out (as configured via midi), the 5500 gets a "No Digital Data". The only way I can get sound to play through the 5500 at all is through line-out from the mac.

Thanks again.

Optical Out. This is a digital signal only.

Here's the situation in a nutshell.

Select the Digital Output in your System Preferences. Your Z5500's will swap from "No Digital Data" when they idle to whatever your stereo effect is set to (Dolby Pro Logic 2 Movie or Music, Stereo, Stereo x2) when they receive a signal over the optical cable.

This is purely a stereo signal. You cannot "select" 5.1 on the Z5500's.

If you play a DVD on your Mac Pro, then the Mac Pro will output the 5.1 soundtrack from the DVD directly out the Optical Port (this is a pre-encoded signal), and the Z5500's will say something to the effect that it's a 5.1 signal and that all 5 speakers are working.

Personally, I've got the Mac Pro setup to play all audio through the Optical Port to my Z5500's. Most of it, save for DVD's, is Stereo only.

Reason/Reaktor/Logic Express all work fine for me. Are you sure your Midi environment is setup properly? What program are you using for "Midi" exactly?

-SC

Hi, thanks again for the response.

While aware that optical output is digital encoding only, I was confused by the default settings from the Midi Settings application which seem to have an option for "Digital Encoding" (or something similar), which doesn't seem to take.

From posts on other forums, some people found that they could only get sound by modifying both system preferences and midi preferences. Simply changing "System Preferences / Sound" to Digital Out (optical) doesn't seem to work in all cases. So I've tried just about every mention you must also change the "Applications / Utilities / Midi Setup" and modify the output settings as well.

So far, no combination seems to result in the 5500 receiving an audio signal. My next step is to eliminate the 5500 or cable as an issue (my PC and reciever also have optical jacks).

I'll post my findings as soon as i find out. I'd post a screen shot of my current settings, but it doesn't appear this is possible in this forum.

Thanks again for all the help.

I had the same problem when I connected the Z-5500 to my G5. It's been awhile but I seem to recall launching GarageBand seemed to resolve this issue for some users.