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Digital Coaxial output to 5.1 Surround system help

Last response: in Home Audio
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August 9, 2009 10:07:32 AM

Hi guys,
I know this may have been asked before, but I have trawled the internet for answers yet have not been able to find anything solid so far. Basically my issue is a simple one yet I have no idea how to fix it: I have a Gigabyte GA-965P-DS3P with onboard digital SPDIF coaxial and TOSlink, and I am trying to connect the coaxial out to a relatively old home theatre surround sound system (which of course also has TOSlink and Coax inputs).

My issue is thus: My computer refuses to recognise my home theatre system as being 5.1 Surround. Realtek HD Audio Manager gives me the option to set 6 channel mode, yet when I click the speakers to test sound, the rear speakers and centre speaker emit no noise, and the 3d audio test fails to create any sound from the rear speakers. In Windows Audio device manager I changed the number of speakers to 5.1 surround as well, which gives me the option in games to choose 5.1 Dolby or EAX, however the rear speakers just copy the stereo output of the front sides, so I can hear nothing at all behind me.

Is there a codec of some sort I need? I have tried using AC3Filter, and setting my audio mode in Realtek HD Audio Manager to "SPDIF pass-through" which I believe means that my surround system is supposed to process the sound, yet I have no sound at all. I believe my sound system is Dolby Pro Logic II.

Any ideas?
August 10, 2009 11:05:13 AM

Just an update here. I have the Realtek ALC888 chip, and the latest drivers available from the gigabyte website. I have tried running the redocnexk application using ASIO4ALL, and I noticed that when I 'start encoding' my Receiver pops up with a 5.1ch light, which isn't on normally, however I get no sound at all. I'm updating the Microsoft UAA Bus Driver now, but I don't see how that will help.

Evidently the Digital Coaxial port isn't transmitting a 5.1 signal (because my receiver does not ahve the 5.1 light active). Is there another way than using redocnexk or AC3Filter (which did not work) to emit a 5.1 signal?
August 10, 2009 3:20:58 PM

Your receiver may have the decoding capability your input produce.

Here is what you should check.

1st - Your PC must be set to SPDIF output and not 5.1 or 7.1 speakers audio out and do not set your PC to decode the signal unless you are using analog connections.

2nd - Amp/Receiver must have 5.1 and up DTS decoder and 5.1 and up Dolby Digital decoder. If your receiver only say Dolby Prologic I or II, Dolby Surround System and not DD 5.1 or DTS 5.1 then you will not get discrete multichannel signal but only matrix from stereo signal. Also not all media have multi coding which it may only have two codec, 2 Channel and Dolby Digital 5.1 are common.

Read more here:
http://www.dolby.com/consumer/technology/tech_overview....

http://www.dts.com/DTS_Audio_Formats/DTS_Audio_Formats....


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Edit:

Your receiver may have...
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August 11, 2009 12:17:23 PM

Set output in Windows Control Panel to "Speakers" and make sure its configured for 5.1. Using the "Digital Output" always produces 2.0 sound. (Drivers will handle weather Analog or Digital is the output signal).
August 11, 2009 3:24:24 PM

Thanks guys.
@Rexter. When you say my PC must be set to "SPDIF" output are you referring to settings in Realtek HD Audio Manager? Because I have it set to 6 channel in Audio Manager, sending signal via coaxial cable. I cannot enable SPDIF passthrough mode however as it stops all sound output from the receiver for some reason.

Because I no longer have a manual for this sound system, I don't know what its capabilities are and cant find a manual online, so I don't know where its Dolby Prologic I or II, and what format it uses. There is a light however on the front that says PCM so I'm assuming it is currently receiving audio in the PCM format.

@ Gamerk316
I have already set my speaker output to 5.1 Surround sound through the "sounds and audio devices" section of the control panel.

I made some form of progress today. I uninstalled the Microsoft UAA bus driver and Realtek HD Audio drivers, restarted and did a fresh install of the latest Realtek HD Audio driver package. When I checked speaker mode under the "sounds and audio devices" of the control panel, the format had been reset to stereo desktop. I changed it back to 5.1 Surround, loaded the Realtek HD Audio (which automatically said 6 Channels) and now I can use the test panel to emit sounds from all the speakers instead of just the Front Left and Right (which was previously all I could do). I tested in 3D audio mode however and the rear speakers still aren't functioning correctly, I think they are just cloning the front stereo.
August 11, 2009 4:44:07 PM

Dang it, I got S/Pdif and Coaxial confused again; sry about that...(need more sleep; 6 hours is clearly not enough...)

Since we established the speakers are connected properly, that leaves us with the source audio, and the upmixing.

What I *think* may be happening, is Pro Logic may be simulating the rear channels by taking the front channel input and reducing the volume (hence, getting a chear rear effect). I'd try turning that off (and leaving Pro Logic disabled until we know exactly the output you are getting).
August 12, 2009 5:05:19 AM

madmanmick said:
Thanks guys.
@Rexter. When you say my PC must be set to "SPDIF" output are you referring to settings in Realtek HD Audio Manager? Because I have it set to 6 channel in Audio Manager, sending signal via coaxial cable. I cannot enable SPDIF passthrough mode however as it stops all sound output from the receiver for some reason.

Because I no longer have a manual for this sound system, I don't know what its capabilities are and cant find a manual online, so I don't know where its Dolby Prologic I or II, and what format it uses. There is a light however on the front that says PCM so I'm assuming it is currently receiving audio in the PCM format.


Running the signal through SPDIF is much different than analog. Digital signal is compress must be decoded and if the signal you are using is only two channels (stereo) then that's all you get. If your signal is multi channel then your receiver must have the decoder for that specific code. If a multichannel sound test on your PC works ok but not to your receiver using spdif it's because the signal may only design for PC system. Only when a proper coded signal is present that it will recognize it, if it's multi-channel like 5.1 AC3, otherwise your receiver will only recognize it as stereo.

You should be able to tell right away if your receiver has DTS or Dolby Digital 5.1 or not; at the front of your receiver it should have writings like Dolby Digital and DTS. If you only see Dolby Prologic or Surround then it does not have the decoder. If that's the case then your best option is analog connection and let the computer do the decoding, however, it might not give you discrete multi-channel signal due to the limitation of your receiver.

Another way to find out if your receiver have DD or/and DTS 5.1 is to go through your amplifier MODE and select DTS or DD and play multi channel movie; if you can barely distinct the front and rear then it's not.
August 12, 2009 10:29:01 AM

I did mention earlier there was a 5.1CH light on my receiver. Believe me, this system is fully DD 5.1 compliant, we used to use it as our surround sound system. I am now convinced the problem is that my computer is not correctly upmixing the stereo to 5.1 as it should be, and I believe maybe this is an issue with my motherboard model.

I have read about programs that you can run which encode all sound in realtime into an AC3/DTS 5.1ch format so that recievers will work properly with coaxial output. It seems that many, many people have had difficult getting home theatre systems to work with digital PC coaxial audio outputs, yet I have never been able to find a solution.

Does anyone know of a live upmixing filter service I can use? (I tried AC3Filter but had no idea how to set it up or run it).
August 17, 2009 1:05:21 PM

The only way for it to work is if your sound chip is capable and if you have the option to select Dolbe Digital Live. Check your manufacturer and see if they have a driver for you to download, if you don't have it then check the Asus Zonar soundcards, what fits your needs.
August 17, 2009 3:15:52 PM

It turns out it is most likely to do with my RealTek ALC888 chipset. Apparently different motherboards have different versions of the chipset that support DD and DTS, but the hardware is exactly the same, only the software is different. That is verified on the Realtek Data Sheet, DD and DTS are purely software mods on the chipset.

In light of this, would anyone know how to obtain a fix or drivers for a DD or DTS enabled ALC888? Someone on another forum suggested changing the MatchingDeviceID to an ALC888 with DD enabled.
My MatchingDeviceID is: hdaudio\func_01&ven_10ec&dev_0888

This can be found under HKEY_LOCAL_MACHINE>System>Current Control Set

Then right click on Current Control Set and click Find, search for Realtek High Definition Audio, and open the string "MatchingDeviceID".

If anyone here has a motherboard with an ALC888 chip that DOES output 5.1 DD correctly, can you check and tell me what your MatchingDeviceID is? Maybe I can change it to get fixed drivers.

August 18, 2009 12:24:05 PM

^^ I have never seen an onboard solution accept DD/DTS encoding. I've seen a few that support decoding though...

Unless you can encode a dolby signal (DD Live) in realtime, or a playing a source already encoded in Dolby Digital/DTS, the best you are getting with a digital signal is 2.0.

I think a soundcard is required at this point. Any that support DDL should suffice.
August 23, 2009 10:00:50 AM

The only way to get more then a 2.0 signal out from a spdif connection is for the output to be encoded in Dolby/DTS formats.The realtek digital out is allways stereo. So you need to use a realtime AC3 encoder that allows you to use "SPDIF pass-through" with sound from any source.

Try redocnexk .
http://www.techbeta.org/audio-media-video/redocnexk-rea...
November 8, 2009 11:24:30 AM

i wonder if you got a solution to this. i am having similar problem with my onboard 888 audio. i know it isn't my receiver because i have another system with old nforce 2 audio and it works fine, DTS and dolby digital. i know the 888 is capable of geting the signal out because using the DTS and dolby digital test it works fine. when i use any player and any decoder i can not get DTS or dolby digital.

i am using vista 64. if you want to test your set up it is at control panel, sound, realtek digital output, properties, supported formats. then highlight DTS or dolby digital and click test. when i do that i can hear the surround sounds and my receiver says DTS or dolby digital. if that can work i don't know why it will not work on video playback.

if i use AC3 filter for playback and select spdif thru i see a message "SPDIF status: Disabled (SPDIF output is not supported)"

if i use the AnvSoft codec and select spdif all i get is static.

i hope someone can help


btw the board is biostar ta790gx a2+
November 9, 2009 11:17:23 AM

No onboard sound solution supports encoding of Dolby Digital/DTS.

To get 5.1 over SPDIF, you need to pass through a Dolby/DTS signal. To convert PC audio to either of those formats, you need Dolby Digital Live/DTS-Connect to encode the outgoing signal from you're PC.

The speaker test works because the test audio files are already encoded in the relevent formats.

You're old nforce2 works because NVIDIA came up with a way to encode to a dolby format, which unfortunally is no longer supported.
January 24, 2010 10:21:33 AM

the older boards with dolby live encode them and send the signal to reciever.for example with coax output when play games with 5+1 support i get dolby.but with the new boards cause of licence problem they dont encode they only send stereo signal.only way to play game 5+1 is with analog outputs from pc to analog in puts to reciever.with movies you can use ac3 filter with coax output.
January 25, 2010 1:35:53 AM

I want to jump in this thread as I too am trying to sort out a similar problem. I will put a post I have elsewhere below. Let me say for the record my laptop has no S/PDIF output. I am plugging my mini RCA into the the headphone jack on the PC. If I enable S/PDIF in FDDShow I lose all sound. I can assure you my preamp has all the bells and whistles to properly decode these sound files.

Hi everyone, I am John.

I am using a Sunfire Theater Grand-IV with a Sunfire Signature 7 400 in a 7 speaker system with no LFE.

I am using a HP Pavilion ZD8000 with Windows XP SP3. The sound card in this PC is an Intel Conexant AC-97. I have a 7 pin DIN/mini stereo to RCA connected from my laptop to my TG-IV. I have enabled dual screen and am playing movies downloaded from the web in AVI & MPEG format. The sound files are encoded in various formats which include AC3, AAC, MPEG Audio. I have installed K-lite codec pack along with Media Player Classic, VLC Player, and the KM player. For the record I like the Media Player Classic most as it gives the most user options in regards to sizing the video and processing the audio stream. For the record Media Player Classic uses FDDShow Video and Audio on most of the movie files I have.

Most of my files are in stereo format simply because of file size and download times. However I do have a number of files encoded in 5.1. I understand I can use a program like ConvertXtoDVD and rip stereo encodes to 5.1 format and play the movies in my Denon A1XV and solve my problem. However its m
January 25, 2010 1:40:16 AM

However its much easier for me to just play the file from my PC as I have these movies stored on a number of external portable USB drives. Movies can be located quickly and easily and I do not have the hassle of searching through a pile of DVD's.

What brought me here is when I play movies encoded in 5.1 format I am totally dissatisfied with the output across the center channel. I have tried all the suggestions and work arounds that come with each player however the only way I can get even close to what I consider to be acceptable sound is to play the movie in stereo and use a setting on my preamp that feeds the signal to all speakers.

I want to know if there is a way to bypass the codecs installed on the PC and send the signal to my preamp for decoding? Is this even feasible? If not does anyone have any suggestions on how I can continue playing movies as I am and solve the problem I am having?

As this involves PC's I will post this in the computer section too.

I would appreciate your help
January 30, 2010 4:11:27 PM

ssregitoss' suggestion was right on! Thanks a bunch!!!

Downloaded this AC3 filter:
http://www.free-codecs.com/download/ac3_filter.htm

Now my SPDIF output to my Denon receiver works like a charm!!! I just use the filter to passthrough whatever the source is.

Tested with Windows Media Player playing DVDs encoded with both Dolby and DTS and YES! I now get all the 5.1 that I've been missing all these times!!! The receiver correctly indicates whether it's Dolby or DTS and the channel indicators (front, surround, back, etc) all light up beautifully on the front panel... very happy!

Anonymous
June 4, 2010 10:47:52 PM

Hi guys, having a very similar problem to the op. finally got fed up and have a free day to fix it.

so, my reciever has DTS 5.1 right on the front, and my mobo says it supports up to 8 channels. my pc never got more then 2 chanels(using s/pdif cable). have tried using ac3 filter, reinstalling drivers, nothing works.

http://www.maximumpc.com/article/howtos/how_to_connect_...
was helpful in making me realize i need to find DTS connect or something similar. anyone know of a way to get a driver for dts connect for Asus M3A78-T board or am i stuck with having to buy one of the $90+ sound cards that come up when i did a search for DTS drivers. Also, has anyone used one of the external USB audio devices (asus Xonar U1) ? and finally is there any possibility of getting a set of analog cables that have the LR, LR surround connects common to audio cards to something that will maintain surround to my reciever?
July 29, 2011 7:38:46 PM

http://www.avforums.com/forums/home-entertainment-pcs/1...

PC digital output to receiver

I got it working fine ;) 
Idea is to pass undecoded sound to receiver, so that sound is decoded there.
Uncheck internal decoder in KMPlayer, I use ac3filter and in it you simply say to pass trough untached for AC3 (dolby digital) and DTS.
!