The S/PDIF Project

[d4phtpunk]

I'm starting this thread because there are questions all over about S/PDIF which can be found in several of VPR Matrix's laptops. I also would not be surprised to find them in the desktop units, as I've found in my research many standard, and probably all high end, sound cards have S/PDIF connections.

First lets get an official definition here. I found this at:

http://www.webopedia.com/TERM/S/S_PDIF.html

Short for Sony/Philips Digital Interface, a standard audio file transfer format. Developed jointly by the Sony and Phillips corporations, S/PDIF allows the transfer of digital audio signals from one device to another without having to be converted first to an analog. format. Maintaining the viability of a digital signal prevents the quality of the signal from degrading when it is converted to analog.

Next I started to look for applications and uses of this technology. I only found one good link, and in an obvious place. It's a TechTV article about using S/PDIF and TOSLink cables to record audio from PC to a Sony MiniDisc device. All of a sudden, I started thinking about every day applications for such a connection... but then I thought, why go through all the trouble of maintaining a pure digital connection to record audio, if the MD player is just going to compress it anyway? How much better is the audio?

Here's the article, check it out:

http://www.techtv.com/screensavers/answerstips/story/0,24330,2421901,00.html

Next, I started looking for cables, schematics and the like. There was no problem finding this information. Here are a couple good links:

http://www.epanorama.net/documents/audio/spdif.html

http://www.andrewkilpatrick.org/projects/spdif/

http://www.motu.com/english/motuaudio/2408/spdif.html

http://www.rane.com/note149.html

and so on....

What I want to do in this forum, is open discussion to everybody interested in S/PDIF usage. Let's gather ideas for application, and if anybody already uses it, please tell us how. Pictures would always be lovely, but an explanation of how you do it, and why would be better! Also, who is actually using the vpr brand cables? Who is interested in the cable pin-outs to make a cheaper cable?

Let's hear from the group!!

-d4pht punk

[Archon]

I have a minidisc recorder, and the Xitel MDPort DG2 (which is what I assume you're talking about ;)). I'll tell you it is a noticable difference (I found) from digital to analog, especially in the SP mode. In the MDLP (uh... MiniDisc Long Play) modes, you really start compressing the audio, LP2 to mp3 quality and LP4 to god knows what.

It did however alleviate a lot of problems I was having, save for the quality, it also puts track marks in the songs, so I didnt have to track manually and do it. (nice.)

Of course, Sony's Net-MD is making this digital SP process somewhat out-of-date. Since it can transfer up to 32x real speed in MDLP (16x @ LP2, 32x @ LP4), SP is used mainly now by people who feel they need high quality sound (and are still willing to wait for it).

But the connection is great, I've done lots with it (from my PC), I've recorded phone calls, taken music from games, used it as an audio player (technicly, it can play ANY audio format, just gotta play it and record it ;) -- take that MP3 players!) :cool: .

[llbbl]

I wasn't even aware of this format. Good research. Thanks for the links!

[Stratman]

I just got one of these laptops and was shocked when I saw the price of the VPR cables. 250 bucks for the parallel splitter cable is complete gouging if you ask me. I'd pay a fraction of that. We could probably even get some of these made at a custom cable place for considerably less.

[Ioman]

Originally posted by Stratman
I just got one of these laptops and was shocked when I saw the price of the VPR cables. 250 bucks for the parallel splitter cable is complete gouging if you ask me. I'd pay a fraction of that. We could probably even get some made a one of the custom cable places for less.

I agree. I think Angus posted and said he though the price was fair...I think its too much.

[Chris Shaeffer]

I wonder if there are some electronics or convertors of some kind in that cable?

A friend of mine and I got a pinout diagram of the parallel port and tried hooking the S/PDIF out from a DAT deck into the pin by pin- assuming that the ground would be standard and we just had to find the other pin.

I'm not surprised, but we had no luck. Could have been several things tjat I can think of:

1) The Sony DAT deck has an unusual level (its an older deck) and the vpr doesn't recognize it.

2) Does the vpr do S/PDIF in? Is it just an output? Bummer if it is. Looks like the XLR connection does offer digital inputs, at least- but that makes my job harder...no AES connections in my studio.

3) The cable has some electronics in it that converts the incoming S/PDIF signal into something the parallel port and its audio hardware/software are capable of using. If so, the cable is worth the $250. The output convertor for the little Sony DAT deck that I have is $200.

In the end, though, it is easily worth it if you need to transfer audio in its digital format. With that DAT, for example, the audio already goes in through its cheap convertors. Do I really want it to go through the cheap convertors again, only to take that twice-converted analog signal and convert it again on the way into Pro Tools?

If you need quailty audio it is almost always best to keep it in the digital domain until you are done with it and ready to mix it all together and record it to its final medium- unless you are dealing with the best convertors and the highest quality analog gear.

Take care,
Chris

[Stratman]

Chis,

Maybe add one more possibility to your list 4) It just doesn't work.

Has anyone indicated that they've actually gotten the S/PDIF to work at all.

[Ioman]

Originally posted by Stratman
Chis,

Maybe add one more possibility to your list 4) It just doesn't work.

Has anyone indicated that they've actually gotten the S/PDIF to work at all.

Angus mentioned in another thread he has gotten his to work I beleive. He paid for those $250 dollar cable from Best Buy and has them hooked up to his stereo at home. I have not tried mine out yet though...

[ToddBradley]

I have a vpr Matrix 200A5. I just ordered the $250 digital audio cable, too. I plan to try to reverse engineer it. And if possible, I'll try to make my own cable based on whatever I find. If you're interested in having digital I/O from your 200A5, but don't want to shell out $250, let me know by email.

[lilteyang]

I used to use S/PDIF with my MD player because it was easier than copying with analog cables...
however, the S/PDIF connection was achieved by optical cable, such is the case with my desktop, Shuttle SS51g.....
I've only used S/PDIF in the cable format provided by 200A5 when I still had a hardware DVD decoder and I connected that to my Cambridge Soundwork Desktop Theater speakers...
The S/PDIF connection provided true AC3 5.1 digital audio, which was the only way I could get my speakers to function at their fullest...
I'll try to hook my speakers to my 200A5 and see if it works....
I'll keep you guys posted...

[ToddBradley]

I learned a ton this week. In short, the digital audio on the 200A5 is pretty much worthless. See all the details here:
http://www.toddbradley.com/ahi_digital_audio.htm#April1

[Angus]

Cross-posted comments from... http://forums.designtechnica.com/showthread.php?s=&postid=10357#post10357

No ****...it's all a sham. Wow, I didn't expect that at all. No offense of course, but I figured you just weren't doing something right and that the glorious tech support people would either A) never call you back leaving us in limbo, or B) you would figure out some error on your part. It's pretty shocking to even me that VPR/Best Buy would do something like this and it totally pisses me off. However, I don't see it as something that is totally unforeseen.

One thing I've learned in life as a consumer of anything remotely high tech is to never buy first generation stuff. With automobiles this is totally true because the first gens are always recalled and any bugs worked out. With computers I never update to the newest operating system (particularlly for business) which is why I'm running Windows 2000 Pro on all my systems including my 200A5. However, I think the awe that was inspired in me when I laid eyes on the 200A5 clouded my judgement a bit and I, like you and many others, bought into first gen gear.

I truly hope that VPR can step up and do something about these issues. They seem willing to offer truthful insight into problems if you prod them enough (e.g. they will own up to the ****ty wifi performance and send you a free card) which in my mind is a step in the right direction. Hopefully they will do the right thing, fix their screw up, and go on about making better products in the future. However, I worry that it won't come since they seem to be shifting focus onto their release of the new systems. Let's hope they don't "solve" our problems by suggesting we buy all new systems.

[prestonmann]

Anyone try to make it yet? If not, I might have a try. I've made 1/4in cables before, but not an XLR, but a buddy of mine has. Honestly. If you want pro audio specs and sound, get a pro audio card. As a music person I was excited by the whole sdif thing and "the cable", but I have designated gear for music and wouldn't really use the 200a5 for that without getting a card like the ECHO Layla or something. At any rate, it would be nice to get "the cable" working and using it to record vocals anywhere...

If anyone has made one, let me know.

[Goldeneared]

Prestonman,
See the thread "200a5 S/pdif" for information regarding the making of this cable. Todd's web site (linked in this thread) has schematics for the nonfunctioning VPR cable. Regards.

[dirht]

I picked up one of those digital cables for the 200a5 (on employee discount when i worked there) - honestly, they never worked. VPR Matrix support didn't have anything on it, and couldn't figure out how to get them to work anyway, so i returned it.