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Discussion Starter · #1 ·
I'm looking to replace my HTPC with a Mac Mini and so far Plex looks like it will work great, however I currently use a Dolby Digital Live card to up-convert all our 2-channel audio to 5.1 surround so that it really fills our large living room.


I've looked into external USB Dolby Digital Live sound cards that work with Macs, but haven't found anything yet. I've also done some research into the Mac's audio architecture and it should be possible to insert a software transcoder into the output chain, but again no luck finding an actual product.


Any advice would be appreciated, and I hope to join the Mac HTPC ranks soon!
 

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I currently use a Dolby Digital Live card to up-convert all our 2-channel audio to 5.1 surround so that it really fills our large living room...
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I've looked into external USB Dolby Digital Live sound cards that work with Macs...

Hey karson, I'm not sure what "Dolby Digital Live," is, but it sounds like a Windows PC concept. There aren't any soundcard upgrade possibilities for most of the consumer Macs we use in the HT. Most of us rely on the Mac's built-in digital optical out to pass the "true" DD 5.1/AC-3 or DTS through untouched to an AVR, then let the AVR decode and manage distribution to the speakers. The optical minijack of a Mini is actually a combo digital/analog output, so if have a video file with 2 channel audio or something that your AVR can't decode (like multichannel AAC) your Mac will pass that over optical as well--as 2 channel PCM--which your AVR can in turn process with Dolby ProLogic II to simulate a surround sound effect.


Not as nice as the real digitally encoded thing in terms of filling a room, which is why most of us go to great lengths to retain AC-3 and DTS.

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I've also done some research into the Mac's audio architecture and it should be possible to insert a software transcoder into the output chain, but again no luck finding an actual product...

The real question, for us to be able to help you better, is: why would you want to "transcode" anything?
 

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Dolby Digital Live is just an encoder to eliminate analogue cableing from PCs to AVRs for music, and allows some PC game play to encode reactionary sounds in real-time relative to the play.


karson, as chef says.. That's really an unnecessary step for mac; Just output from it's digital optical (common port as the analogue out) to your processor. Use PLIIX surround simulation for any 2 channel sources (should be included in most any AVR processor sold in the last several years).


For gaming.. Any games on the mac worth their salt software encode real-time play audio into their output. I'm not a game player, but this is what I'm told from those who are...


ken
 

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Discussion Starter · #4 ·
 Here's a summary of what DDL does . In a nutshell, it passes through AC3 and DTS untouched to my receiver, but converts 2 channel audio into 5.1 AC3 so that it's output over all speakers in the HT. The reason I do that is our living room is 30'x20' and the volume throughout the room is much more even when played over all 6 speakers instead of just the fronts at one end of the room.


Unfortunately my Sunfire can't automatically switch between different Dolby modes on the fly and I don't want to bother doing so manually, so I need something a bit farther upstream to accomplish what I'm looking for.
 

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Here's a summary of what DDL does

Thank you for that link, karson; it does seem DDL is largely, if not entirely, a Windows PC construct. Which means if you're considering a "switch" to the OS X home theater side of things you may be stuck with a solution in search of a problem that the rest of us don't share.

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Unfortunately my Sunfire can't automatically switch between different Dolby modes on the fly...

Can you be more specific about this? Do you mean that if you:


1) play one video file back that has DD 5.1 audio your Sunfire correctly recognizes and decodes the DD 5.1?


Then


2) when you switch to a second video file that happens to have DTS audio your Sunfire correctly recognizes DTS and switches to decode the DTS?


Then


3) when you switch to stereo audio, say from iTunes, or to a third video file with stereo, 2 channel PCM or indeterminate audio--basically anything else that doesn't have an encoded digital audio track (AC-3 or DTS)--your Sunfire doesn't know what to do, sits there silently and won't just automatically switch into "Dolby ProLogic" mode? You have to do that manually?


If that's the case, and if your Mac mini purchase is imminent, I suspect you're better off replacing that Sunfire than you are forcing a DDL solution in OS X merely to feed all audio to it as artificially created encoded AC-3. I just did a quick Google, but it doesn't appear that folks with Mac Pros booting into Windows can even do DDL. Plex has a lot of nice audio handling abilities, it can transcode, say, DTS to AC3, but that won't be your solution, either; I don't think Plex can transcode 2 channel into AC3 so it is passed through by CoreAudio as an encoded AC-3 stream.


But, really, Dolby PL II has been around a good long while. At the moment I have two Harman Kardon AVRs in the house, an AVR 325 and a DPR 1001, probably 8 years old(?) both are wonderful, each input can be uniquely defined with very customizable defaults and behavior, including auto-detecting and switching from DD 5.1 to DPL II to DTS to DPL II on the fly effortlessly. I had thought this was pretty standard, and it sure makes things easy Mac home theater-wise.

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I don't want to bother doing so manually, so I need something a bit farther upstream to accomplish what I'm looking for

Long term, I think you're better off looking at this differently--you don't need something "farther upstream."


I know this isn't the suggestion you were hoping for, but maybe the smarter move on your part is a clean break: instead of pursuing a similar solution to the one you cobbled together for your Windows HTPC and Sunfire, you remove the proximate cause of your issue, which is the inability of your Sunfire to handle something so basic.
 

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not sure which Sunfire processor you have, but I doubt that to be the problem here. Sunfire products have supported PLIIx since it's inception, do format switching when sensed; The latest models even have surround matrix holographic modes from 2 channel sources that arguably surpass PLII; They even have input auto signal sensing that power-up the processor when they sense an input audio signal; In short, Sunfire makes some of the best audio processing gear available...


IMO, Live's conversion of 2 channels sources of pre-programmed media, is inferior to anything done downstream by your Sunfire. It's purpose is to allow an interactive game developer under Windows to encode game surround sounds into the stream in real-time relative to the player's actions.


DDL is a system offered for such a game developer under Windows; On the Mac Core Audio supports such capability if you have proper plugins and or system (that's up to the Mac game developer to use or not); Even Apple's own Logic Studio software provides AC3 encoding for 5.1 (or even 7 channel) surround output...


The only question I see here is, whether karson is wanting Games that use that surround encoding for their output and that is a question for the game developer, not the Mac or Sunfire capability. If the real-time Game surround is not part of the issue here, then any 2 channel media output from your mac to your Sunfire will use the Sunfire to process simulated surround (which is all the DDL system is capable of anyway, unless specifically being programmed to encode sounds into the surrounds like a game play)..


ken
 
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