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2 topics: 1 - Can Dolby Digital 5.1 speakers support Dolby Digital TrueHD? 2 - How does SBX Pro/Surround produce sounds above & below?

post #1 of 2
Thread Starter 

This is a 2-topic thread because I like to conserve forum space.

 

1. I have Logitech Z-680 THX-Certified Dolby Digital 5.1 / DTS 5.1 speakers with appropriate Dolby Digital & DTS decoders. Can they support Dolby TrueHD? I assume they don't because Dolby TrueHD would probably require Dolby TrueHD decoders and I doubt Dolby Digital decoders can decode Dolby TrueHD signal. Am I right? Are there any soundcards that can encode Dolby TrueHD? 

 

2. SBX Pro/Surround, just like Dolby Headphones, and CMSS-3D is a 5.1 / 7.1 surround sound virtualization technique for headphones. However, it is also advertised as being able to virtualize sounds above & below! How is that possible? You can only have 5.1 or 7.1 channel signals that get downmixed to stereo that is then sent to stereo headphones. Where would above & below signal be coming from? I assume it is supported by a very limited number of programs/applications as I've never even heard of a media technology that would support that, let alone a game or a movie... I can't seem to find the exact page I was looking at, but they the "above & below" sound is what they are talking about when they say "Go beyond ordinary 5.1 and 7.1 solutions with an enhanced sense of audio depth and spaciousness by creating virtual surround sound channels via SBX Surround." I wonder if they key word is "creating" ???

 

Thanks ahead of time :D !

post #2 of 2
Quote:
Originally Posted by MonarchX View Post
 

This is a 2-topic thread because I like to conserve forum space.

 

1. I have Logitech Z-680 THX-Certified Dolby Digital 5.1 / DTS 5.1 speakers with appropriate Dolby Digital & DTS decoders. Can they support Dolby TrueHD? I assume they don't because Dolby TrueHD would probably require Dolby TrueHD decoders and I doubt Dolby Digital decoders can decode Dolby TrueHD signal. Am I right? Are there any sound cards that can encode Dolby TrueHD? 

 

2. SBX Pro/Surround, just like Dolby Headphones, and CMSS-3D is a 5.1 / 7.1 surround sound virtualization technique for headphones. However, it is also advertised as being able to virtualize sounds above & below! How is that possible? You can only have 5.1 or 7.1 channel signals that get downmixed to stereo that is then sent to stereo headphones. Where would above & below signal be coming from? I assume it is supported by a very limited number of programs/applications as I've never even heard of a media technology that would support that, let alone a game or a movie... I can't seem to find the exact page I was looking at, but they the "above & below" sound is what they are talking about when they say "Go beyond ordinary 5.1 and 7.1 solutions with an enhanced sense of audio depth and spaciousness by creating virtual surround sound channels via SBX Surround." I wonder if they key word is "creating" ???

 

Thanks ahead of time :D !

 

The Z-680's audio hardware may not have been designed for decoding Dolby TrueHD or DTS Master Audio, but the Z-680 can play TrueHD/Master Audio once something else has decoded it, before the audio signal is sent to the Z-680 speakers.

I'm assuming this is for playing Blu-ray movies on a windows PC?

I use Cyberlinks PowerDVD 11 Ultra as it can decode TrueHD/Master Audio for playing Blu-ray movies, the software was $30 on eBay.

If you got a used Asus Xonar DX or D1 sound card (used, $60), with it's nice CS4398 DAC chip, you could connect the DX/D1 to the analog inputs on the Z-680, using the black/orange/green cable that come with the Logitech speakers..

http://www.ebay.com/itm/Cable-for-Logitech-Z-5300-Speaker-System-Color-Coded-3-Minijack-Audio-Cable-/360897118199?pt=US_Audio_Cables_Adapters&hash=item540724fff7

With this setup your bypassing the digital audio section on the Z-680, which you really do not need as the Xonar DX/D1 card handles the Digital to Analog Conversion (DAC).

So the 6-channel (or 8-channel) TrueHD/Master Audio comes off the Blu-ray disk, then is sent to to be processed by PowerDVD, then the audio is channeled thru the DX/D1 DAC chip, then send to the 6-channel of analog output from the sound card to the black/orange/green inputs on the Z-680.

 

Headphone are sent a specially processed 2-channel audio stream, which started out as a 6-channel or 8-channel signal.

We only have two ears, so it only takes two speakers/diaphragms (one in each headphone cup) to make our ears hear "virtual" audio.

So the 2-channels of audio that is sent to the ears have been processed with whatever audio tricks are needed to create a 360 degree and up/down audio field.

(Somewhere some really smart audio engineers sat in a sound studio and figured how to do this).

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Head-Fi.org › Forums › Equipment Forums › Computer Audio › 2 topics: 1 - Can Dolby Digital 5.1 speakers support Dolby Digital TrueHD? 2 - How does SBX Pro/Surround produce sounds above & below?