Digital sound on Chorus MMDS

Hugh McManus

Hi,

I've just been switched to chorus digital on MMDS from analogue. I've got a lot of good audio kit, so I want to get the best audio signal possible from the box. It's a Sagem and has an output labelled "audio L/R digital". There was no manual. The chorus website has a picture of the connections, but it labels this an RCA connection, which it patently isn't. It's obviously a mini jackplug socket of some sort, which is odd for a digital signal cable.

At the moment I'm just using the stereo analogue output from the TV into my sound processor, but I'd like to bring the digital audio into play, if possible.

Does anyone know the correct way to get this connected up? I've had no joy from "customer service" at the chorus website.

Thanks.

steveon

I think its a Digital Coxial Cable


Have a look at this site you might find it useful
http://www.audiovisualonline.co.uk/dynamic/eshop_categories.set/ref/3/browse.html

Hugh McManus

It should be a digital audio cable, from what it claims to do, but it's clearly not a normal digital audio cable socket. I have some digital audio cables connecting other components, such as my DVD player, but this is different. Physically, it clearly take a jackplug, but there's no way for me to know how many contacts on the jackplug or how it's to be wired. Logic would dictate 2 contacts for a digital signal, but I've never seen a coaxial digital cable with a jackplug, so God knows what they've put inside this thing.

watty

Thats the French Well they did design SCART for us.

Either it's Analogue 3 connections, Digital 2 connections or not enabled.

Sponge Bob

contact Chorus customer support who must surely have come across this question before .

steveon

without getting banned I can tell you I previously worked as a chorus installer and they couldn't tell me what the name of the connection was as people were constantly asking me. Dunno why they didn't leave it the same as all the other boxes.

But I will my contacts there and see if I can come up with anything as It surely serves some purpose

steveon

Wondering if it might be an Optical Digital Cable connection, does your sound system have a coax input or maybe u could convert the optical digital connection to coax and then maybe from coax to RCA

Be of interest to you,
http://www.nexxia.co.uk/Audio_Connectors/Optical_Adaptors.htm

One of the great things about digital signals is that you don't have to worry so much about the cable. Any cable that does not screw up the signal so bad that the input can "understand" the digital signal will work just fine. A "better" digital cable may allow a greater distance between sender and receiver, but it will not sound any better. I'm not trying to start a "which cable sounds better" debate here, but I do have some knowledge on the subject since I'm a Computer Engineer.

One good thing about an optical cable is that there is no chance of introducing a ground loop. This is particularly important when connecting a HD tuner to an audio system.

One good thing about coax is you can often use longer cables than you can with optical. This seems to be because of the signal loss with most of the Toslink cables available today. After about 40 feet the optical signal seems to get too dim for the input, so there is no sound.

Hugh McManus

I've been looking at the specs of similar looking boxes on Sagem's website in the meantime, as a result of which I now suspect it takes a 4-contact jackplug, to be used with with 3-RCA on the other end, with red and yellow giving analogue l/r and yellow giving digital audio (when enabled). However, I don't think the box is digital-audio-out enabled. (There's an istallation menu item that only appears if digital out is available, and it's not there on the chorus box.)

Anyway, I'm not going to bother with taking a stereo analogue signal out of there, since I'm getting that via the TV already. I had assumed that Chorus would be offering Dolby digital or DTS on Sky Movies channels, but this doesn't seem to be the case, so my whole question is somewhat moot. It does raise the following question though: given the number of people who have half-decent AV equipment in their homes and who are used to at least dolby 5.1 from their DVD players, I wonder how come Chorus, when upgrading anyway, didn't bother offering people the sound quality that they're used to and that they can get via satellite from Sky?

watty

The Sony Minidisk has a socket which is analog 3.5mm audio jack OR an optic fibre for digital. I wonder is that what they have used?

Anyhow it is unlikley to be enabled for Digital.

The DTS or Dolby 5.1 uses a separate data channel. Chorus use many analogue links that only do mono, or sometimes support a Nicam carrier, but only if the source had Nicam. NIcam won't be passed over any Chorus digital cable/MMDS. On their own MPEG2 encoders for Cable & MMDS, it is likely they can only encode stereo MPEG1 Layer 2 audio, i.e. MP2 as part of the MPEG TS.