5.1 sound cards for Mac?

Question

I've been searching around and I've seen mixed reports of different sound cards working or not working for Mac. I'm aiming for the Creative Sound Blaster X-Fi Surround 5.1 card (SB1090). (Amazon link: http://www.amazon.com/Creative-Labs-SB1090-Blaster-Surround/dp/B0017QQQAE ) The only issue is that there is no volume control which is actually not an issue since my 5.1 surround receiver has one of those. I've seen nothing about the actual 5.1 working.
I've also heard about a Zalman 5.1 card (Amazon link: http://www.amazon.com/Zalman-ZM-RSSC-External-Sound-Card/dp/B0001OZ2K8 ) that I've read reports of fully working; 5.1 and all.
I'd like a collective opinion, and suggestions of which card I should buy. Thanks in advance.
Message was edited by: osxdude

Answer 1

Hi Jeffrey
Jeffrey Lee wrote:
Hey Bob
You are right... Apple's foray into multi-channel audio is a mixed bag.
I have just today raised a bug request asking for Apple to produce a Tech Note (or whatever) to explain the situation. If they do this (and do it right!) then this might act as a definitive source.
AC3 is what Dolby is(and probably always will be) for 5.1 audio on DVD's. This is a compressed matrix audio stream, and it is not full bandwidth on any of the 6 channels.
Yes, but it's changing all the time. I see there's now an uncompressed multichannel version called TrueHD.
I own a M-Audio FW410, which does have 10 separate audio outputs, but the only way to make use of those is with an application that specifically allows that to happen. In my case, Pro-Tools can see and make use of the different channels... perhaps a stereo pair for the control room, and a stereo pair for headphone monitor mixes. I also have a DJ program which allows for a stereo pair for the main speakers, a stereo pair for headphones, and a stereo pair for the DJ booth speakers. In all cases, these are full bandwidth channels, nothing is compressed, and all handled specifically by an application designed to use multi channel outputs. But there is no way for me to use those while playing back DVD's on my Mac, as there is no decoder on board, which is the first thing that has to happen to get 6 discrete audio channels out of an AC3 stream. The DVD app just can't do it.
If you mean Apple's own DVD Player, then I think you're right. However, I have used the free VLC player with my little Hercules USB card to play DVDs in true 5.1 audio. I recall I have to use Audio Midi Setup first, but it works ok. It would really be worth your while trying this with your multichannel system. You can probably use Audio Midi Setup to nominate 6 out of 10 speakers for the 5.1 channels.
I'm not a gamer, never have been so I'm skating on less than thin ice here, but there are only three options as I see it for games.
The first is the audio is only in stereo. In this case, sending it via analog or digital to a receiver with Dolby Pro-Logic would give you 'fake' 5.1 surround.
I'm not sure you'd even get that! I think you'll only get stereo from the front two speakers.
The second is that the audio is an AC3 stream, in which case, sending it out of the optical outs to a receiver would properly decode it into 6 separate audio channels
Yes, but that depends on the game having AC3 content. With the power of the Core Audio 3D mixer it's not the way I'd do it, but another developer might see it differently.
The third is, like the audio programs I mentioned above, the game has the ability to assign certain channels to certain outputs in any combination from stereo to 3, 4, 5, 6, 7, 8 or more channels. As I said, I'm not a gamer, so have no idea of what the options are, but I'm guessing the last option is the least likely.
For that, you'd still need a separate FireWire or USB sound card.
NEITHER of the OP's device suggestions have anywhere near 6 discrete audio out's, so at best passing a digital signal to a receiver is the only thing he can do with those choices. My guess is most PC's don't have any kind of built in digital audio output, so for those kinds of computers, either of his choices would make sense. But since most modern Macs have a digital output to begin with, I stand by my original post.
I try to avoid PCs so I'm not up to date with their current abilities.
The Mac's multi-channel ability is compounded by Blu-Ray, who's HD audio streams can be multi-channel un-compressed, full bandwidth audio. The only way to access that audio directly from a BluRay disc is from discrete audio outputs on a Blu-Ray player, or thru an HDMI cable to a receiver who can handle that kind of audio stream.
BluRay can use TrueHD on (IFRC) up to 8 channels, but I don't think it's compulsory, so there may be BluRays out there which use compressed AC3.
I've ripped a few BluRay discs to my hard drive, but with the sad shape of HD playback on Macs, I'm mostly limited to listening to the AC3 streams, decoded by my receiver. +(Presumably, the newest generation of Macs allow for HDMI outputs, including uncompressed multi channel audio)+. I have had a limited amount of success using VLC for playback, and assigning the individual, uncompressed audio tracks to different outputs on my FW410, but haven't invested in the cabling necessary to hook that up to the discrete inputs on my receiver(and probably never will), but at least it SEEMS possible.
This is why we need a definitive answer from Apple. I'll keep you posted with the progress of my bug request, but I'm not holding my breath for anything soon.
All the best
Bob