5.1 audio cd question

i was given a few 5.1 audio cd's someone mastered.. i saw these playing on one of those combined 5.1 dvd player systems and they worked fine.

when i got home i tried the same cd on my system, i have a DVD player connected via coax to my sony 7.1 DTS DD receiver, and i got nothing, the DVD player correctly identified the disc as a DTS disc, and the tracks are playing, but there is no sound at the amp, there is no recognition of any signal whatsoever, i put in a DVD or CD and it works great via the same connection.

as a test, i put the same 5.1 CD in another all in one combined surround system ( that also supports DD and DTS) it too identified the disc just fine and was playing, but no sound again..

i put the CD i nthe computer or regular CD player and get pink noise, and the tracks are identified as a CDA track in windows explorer..

i can play the disk however in windvd, which defeats the purpose of the disc as i want it on the main system using the DVD player..

what could be wrong?

is my DVD player screwing with the digital signal so the amp cannot decode it? i have tried forcing the amp to look for PCM and in DTS and every other setting and button avialaboe but to no avail, i figure if this is mastered badly even though i saw and heard it working on one system why is it that 2 other systems cannot play it at all?

if it helps the system that played the disc origionally was a philips all in one DVD DIVX 5.1 player and i am trying it on a memorex DVD coax out into a sony de-697 receiver or on a oritron all in one dvd 5.1 system... none work

help please

 

Interesting problem.
As a little bit of background, these discs - AKA DTS-CD - are a special form of DTS encoding - DTS-WAV. This takes the 5.1 discrete mix & encodes it to a standard DTS stream, but with fudged headers that identify the file as a 16/44.1 Stereo CD comppatible track, which is what allows it to be written as an Audio CD. This is why it shows in Windows explorer as a CDA track.

What should happen - as long as your DVD player can pass the bitstream untouched - is that it outputs the bitstream as DTS, and it needs to be decoded by the DTS decoder in your amplifier, or alternatively internally in your DVD player & output as 6 mono analogue streams.
Is your DVD player happy about passing a digital bitstream? In the players firmware, is there a setting for digital audio out, and is it set to RAW/BITSTREAM or PCM?
Does the player actually pass a DTS signal correctly - this can be tested by trying to play a DVD with a DTS stream, and seeing what you get at the amp.

This has to be either a setup issue or a compatibility issue. Something, somewhere, is not plugged in correctly.

 

when i put in a DVD with DTS on it, say priates of the carribean or Lord of the Rings the receiver happily states it is receiving a DTS signal, and the appropriate lights and speakers light up on the display, normally it will say something like DTS-ES or DTS and the DTS graphic will light up on the display, as will the speakers that the system uses ( 5.1 or 7.1 depending on the audio input) the DVD player has on the front DTS Digital out as a graphic...

the other system that i tried this on is an all in one system ( no connections to amp or player all integrated amp/dvd/tuner system, which also accepts DTS but will not output any sound either even though the disk is playing and the DTS logo is lit on the display.


as you say it is a fudged header i feel the disc is mastered badly, since all other pure surround formats work.... on both systems, (windvd coincidentally plays it fine)
I have tried to changesettings on the DVD but there is no setting for the digital out, but as i said other DTS sources work fine

i am trying to obtain from a friend another 5.1 audio disk to see if it is the player or setup.... but it does seem more likely to be the disk...

i will try some other things aswell and will let you know thanks for the help

 

It's not the disc - assuming it was written & encoded correctly.
Where I think the problem lies - and it is down to your amplifier/decoder - is that DTS-CD uses a 44.1KHz header, so the format will write to CD-R.
Comparing this with DVD is illogical, as the stream on DVD will be either .dts or .cpt, and will be at 48KHz as well.
The player is telling me that it is simply outputting the stream correctly, but my guess is your amplifier is looking for a 48KHz signal.

I have written - and also bought official from DTS-Entertainments - many of these discs. Your problem is setup related.

 

The notion of "5.1" audio can get very confusing and is often used erroneously. It has become something of a generic term for two fronts, a front center, two rear and a sub (the ".1" is the sub). Please know, however, that "5.1" in its best and truest form is ... dare I say it ... ANALOG! Six seperate ANALOG tracks each independantly recorded and the sound is awesome! Please take a look at the pic below: you'll have reg two channel analog, dig optical and dig coax inputs and below you'll notice the 5.1 outputs ...yes, six RCA analog cables.




I'll try to find a link I can post that will explain it better than I can. I believe Ced had posted something in displays that I can borrow. I found one thing but it isn't good. I'll keep looking for something that will explain it well. If the back of your DVD player has the six 5.1 analog RCA outputs and your AVR has the six 5.1 analog RCA inputs to accomodate them, CONNECT THEM!!! along with the optical or coax ...contrary to popular opinion, they're NOT the same thing at all!!

 

5.1 does NOT need to be analogue - although the outputs from players generally is unless you are using HDMI or FireWire.
This is only because the coaxial or lightpipe connections are not capable of accepting a 5.1 24/96 stream, and not because analogue is percieved as being "better".

However.
These DTS-CD discs are genuine, discrete multichannel 5.1 surround.
Unless they are upmixes, of course. In which case they will still be 5.1, but sourced from stereo originally & fiddled with.
They are, when encoded correctly, discrete multichannel.

 

You're absolutely right, it doesn't NEED to be analog. What I'm suggesting is: if one has both a DVD player and AVR capable of connecting the six RCA cables, it is well worth it as, unlike say the optical and coax, it isn't a redundancy. Depending on the disc, the digital MAY sound better but (particularly in the case of big budget movies) those six analog tracts had a lot of effort put into them and can be absolutely amazing. If one's equipment is capable of both types of connections, its well worth the trouble.

http://www.hometheaterforum.com/htf/archive/index.php/t-237627.html


I'll try to find something with a good solid explanation: Diabolos (Ced) had posted something; I'll see if I can find it or maybe PM him. If one has equipment capable of it, it's sure worth the effort.

 

Oh, good grief yes it's worth it.
The better the DAC in the player - and the number of them too - the better. Players like My Denons (2910 & 3910) have multiple DAC, but the cheaper ones will only have the one.
Digital output from SACD & DVD-A can only be done if your player/Amp will accept HDMI or i-Link/FireWire - And the quality will vary greatly, depending on whatever DSP the amp might be going through. Some actually take the 6 analogue inpts from the RCA jacks, and then digitize it again to use internal cheap & nasty DSP processing! The amp absolutely must be capable of not doing this, and again the cheap ones all do.

The thing is, the Audio on the discs is still digital, no matter what the player does with it. And a Dobly Dirgital encoding is not as good as DTS Core, and DTS core is not as good as DTS 96/24, and none of it is as good as MLP Lossless.
It's still all digital. Even the cinema masters for cinematic use are digital. The encoded files are written to an MO disc, and shipped with the film stock, and it's all synced up at the cinema. SDDS is imprinted to the film stock, I believe.

But it's still all digital.
Where a lot of players get it badly wrong is the copy protection on some DVD-V discs will truncate to 16 bit & downsample to 48KHz - and it is this truncation that sounds ugly.
Always better to use the 6 RCA jacks if you ahve them available, and have decent DAC in the player.

 

Hey Guys,

New to your forum. I am having somewhat of a challenge myself.
I am using the head phone/optical output from a new Imac to feed itunes to a sony receiver, which has a coax input. According to the sony manual, by using the coax input, the speakers will play louder than using the analog ports on the receiver.

If I connect a one-in (stereo mini jack)to the output of the Imac & split it off with a two-way (left & right channel)with rca's & plug them into the cd input of the sony, I have sound, o.k.,but not loud enough.

If I combined the two rca's into a single rca & plug it into the digital coax of the sony receiver, I hear no sound.

Can anyone give me insight on this challege??

Thanks for your input.

 

What is the output level from the iMac?
Odds are high it will be at -10 dBV Line level, and a CD input could well be at +4 dBU, giving you an impedance mismatch.
Try plugging in to a different input - tape or similar. If this is still too low, then you need to get a line amplifier.

That is because you are mixing connections between analogue and digital. You cannot put RCA L+R analogue outs into a CoAxial Digital input!!

 

And this has what exactly, to do with either 5.1 Music CD or High Resolution???

 

Thank you for your replys on the Imac/Sony receiver challege.

I appreciate the bit on the line amp. I do understand that if I use the cd inputs, the preamp/line level signal from the Imac will be always analog, rather than digital. This may have to be my trade off, if I cannot capture the digital coax input properly.

Thank you for the clariffication, on not combining two rca's into a splitter, than pluging it into the coax input on the sony receiver. Is it my understanding, that the proper cable would be a stereo sheild type, with a mini jack on one end to plug into the Imac, & a rca on the other end to plug into the sony receiver????

My present layout is the following. From the Imac location,I have two rg6 quad shield & one cat5e cables that run to a central closet. From this same central closet,I have one rg6 quad plus one cat6 & one cat5e that terminate @ the a/v location where the sony is at. The above mentioned cables are not being used @ this time, can I use them for this coax connection?? I may add that, the total cable distance from the Imac to the sony is around 100'.....I hope the distance isn't bad.

So, maybe I can incoporate connectors on the ends of these unused cables to interface a proper digital audio connection.

THANK YOU ALL FOR YOU RESPONSE!