[kramer]

Hi all,

I have a Technics SA-DX940 amplifier which can encode DTS & DolbyProLogic, and i have connected the SPDIF output of my IP35 to my amplifier with a TOSLINK/optical cable. I beleive I have done all the available settings, but when I try to play a DVD or a .MKV with 5.1 sound, or try to test Decoding options thru vista sound settings, my amplifier does not show any connection/decoding info and i dont hear anything... (i know that it shows a DTS or DD logo when i connect it to my DVD player, but nothing comes up when connected to PC).

Below are screenshots of all the settings i made/could find, please have a look and tell me whats wrong








If i select SPDIF at the 'AC3 AUdio Decoder' properties, the green bars in 'AC3 Filter' goes away, and i still cant hear or see any sign of digital sound on my amplifier...

any help/ideas are appreciated.

I also have a cold-boot problem sometimes, but i'm saving that for another topic lol.

[dostov]

Is that with the latest Realtek drivers installed?

Also, do you have another audio device installed?

I had a pretty hard time having audio working through optical on Vista but I don't quite remember exactly what I did that made it work in the end. I now installed HDMI cables and switched to audio-over-HDMI and the nightmare began all over again.

I use 48Khz and it works in 2 channels. But when I test DTS or DD in the control panel it doesn't work so I wouldn't rely on that too much if I were you.

Digital audio under Vista is always a bunch of fun. But if AC3 filter doesn't work either, well it's not looking good.

Good luck!

[.aT]

(No, dostov...I am NOT stalking you, lol. Promise.)

Kramer...if you check back in this thread, here's some thoughts.

Before I went with XP Pro Sp3 on my new build, I installed Vista 64. This included using the Realtek (RT) HD Audio I have onboard, same interface you have shown.

-RT will not necessarily popup an onscreen notification when you plug your optical cable into SPDIF output like it does with other audio output plugins, at least, it did not with mine...not a problem though, it is there and works great, although I use a SPDIF RCA cable instead of an optical.

-in the RT audio interface, goto I/0 and click on the configuration button for DIGITAL. You need to put a check in the box "output digital audio source."

-if you have other speakers hooked up to "normal" speaker outputs, they will still work as well. Enabling SPDIF does not cancel them.

-when you look at your mixer/volume controls, to output SPDIF, be sure the SPDIF volume control is not muted. There may be a volume slide control, maybe not. My new build does not have it, only mute on or off but my older Abit mobo has volume for it, as well. Master volume on my new build does not effect SPDIF, only WAV volume control. Yours may or may not.

-I have an Onkyo 6.1 DTS Surround Sound System (luv'it!) and allow it to do all my processing for HTPC purposes. I set AC3 Filter to AS-IS NO CHANGES and feed directly out. I do not put a checkbox in USE SPDIF or let AC3 Filter do anything as far as processing for Dolby or DTS, etc, that's whay my Onkyo head unit is for. No sense in trying to process the signal twice, will only degrade the signal. If I am watching a tv ep or movie in divx or xvid format from the pc, I will set my audio output to quad channel in windows and AC3 Filter but use all'channel stereo on my Onkyo. I get the best results that way, sounds great.

I'm darn tired right now and I know I'm leaving a thing or two out but just in case you're still having problems and actually still visit here after your one post, That should be enough to get you going.

My final advice for HTPC...BSplayer, AAC Video and Audio filter, latest Divx decoder, latest Xvid decoder, Matroska Media Splitter, etc. I get much better results with AAC and Matroska Splitter than using FFDshow. Anyways, that's it for tonight. Hope you fixed your problem but if not...

[kramer]

i've found the cause of my problem.
i had a pretty long (10meters) optical cable, and it seems that there happens a big loss of signal/light cos of its length. when I used a shorter (0.7m) optical cable, it worked perfectly.

but, the thing is my amplifier is at the living room (or 'theatre room' as i want to call it; using a projector ) and my pc is at my own room. so i cant always use a short cable. my temporary solution until i find a better one is: using my laptop as video/audio receiver located in living room (streaming content thru lan)... i wonder if theres sth like repeater for optical cables...

[.aT]

Great that you figured that out, Kramer.

I am using either a 12' or 20' fiber optical cable for my HTPC...sorry, can't remember which. I am having no problems.

I do remember reading something somewhere about 6 meters (about 20 feet) being the recommended maximum length and that up to 15 meters is possible but with a quality cable.

They do make optical cable boosters and you can do a search on the same and come up with many results; ie, optical cable booster. I do not know anyone using a booster, all of my friends use one cable and have had no problems, as well.

If the cable has been damaged in any way (stepped on, bent, crushed, etc.) or is at a non'smooth angle somewhere in it's route, it can also cause failure.

How far are you talking about, from your pc to your head unit?

And I'll post this note about coaxial cable, in case someone sees your title and is seeking help on SPDIF using it. One might be able to get away with using standard shielded RCA cables but for the best sound and to be done properly, 75 ohm impedence cable should be used so the signal terminates properly, no matter what the length. Using coaxial for SPDIF, one can easily reach 10 meters (33 feet) when using 75 ohm cable. Me? I'm using a standard 10' cable right now, lol...just haven't ordered a 75 ohm cable yet.

So on my HTPC I use optical, on my new build pc I use rca coaxial.

Hope something in there helps you.

[dostov]

I would consider trying another cable if I were you Kramer. Signal loss on an optical cable is far less than on a RCA cable coax as far as I know so you shouldn't have problems with a 20' cable, unless it is of a very bad quality. But as .aT pointed out, yours might be damaged. Did you run it through the walls? If so, it might have gotten stuck in a tight bend or been ripped open on a nail.

Cheers!

[kramer]

yup, my cable run thru many tight places (and its length is ~35' for us peeps). that may be the problem. i can see the light personally (with my eye) but my amplifier doesnt recognizes the signal coming from the long cable. (eventho i didnt investigate further) i believe my amp doesnt have coaxial input, so thats not an option for me.
also, yup again, i used a cheap cable. quality ones were kinda expensive for my budget (55€ for 35').

oh well, i guess i'll continue using my laptop as receiver...

[.aT]

I hope I get this reference number right...I believe I read somewhere that a 5mm cable is what is needed for longer distances. Guess that implies quality size, don't know but that's how I remember it. I'll quit being lazy and get a measuring tape on my optical cable tonight and see how long it is and reply back. I might even still have the box for it.

So when you said you didn't have coaxial input in your receiver, are you saying that you do not have individual RCA inputs for Front Speaker, Back Speaker, Center, Sub, etc? Or did you just mean you don't have a SPDIF Coaxial input...I looked up the specs for your mobo and knew you didn't have SPDIF Coaxial output from your mobo but thought perhaps if you had individual inputs in your receiver, you could more easily connect up that way.

[dostov]

Yeah but going analog on such long distance will destroy his sound quality. Going for optical digital and ending up with terrible sound quality over analog would get me depressed personally...

I'm sure there's a fix to the cable problem and a better cable might just be it when money drops by.

[kramer]

i have 6ch input in my amp; and was using 6 seperate RCA cables from PC to amp before. but things started getting messy and the whole cable mess made me angry... also they were making terrible static noise. so i decided to use optical cable.

btw i meant: i dont think i have coaxial digital input in my amp.

[TUBBYTUBB]

I don't know where your located at,about the optical cable booster but radio shack used to sell them when I worked there as manager but that was 3 years ago,sorry I'm not more help.


THOMAS