S/PDIF output trouble with 002

[Faulty Records]

Hello all,

I have been suddenly unable to get a good S/PDIF output signal from my 002 using the configuration in my signature (intel mac, PtLE 7.1.1 cs2).

The problem exists on new sessions, as well as old ones that used to work. My current sessions are at an 88.2 sample rate and 24 bit.

I have run RCA cables to my Rosetta 200 S/PDIF in and my JBL LSR 4328 S/PDIF in, and neither can lock.

I've checked the cable by routing the Rosetta S/PDIF out to the Rosetta S/PDIF in, and it locks fine and converts audio to digital and back perfectly.

I've trashed my Digi prefs (both on the individual hard drives, and in the system drive's Library/application support/digidesign/databases).

I double checked my I/O settings.

I've done a complete uninstall, including all plugs, and reinstalled, ran cs2, reinstalled Music production toolkit - and nothing.

Any suggestions?

Sincerely,
David

[Slim Shady]

How far is the cable run? RCA cables will work for S/PDIF for short runs (2m or less maybe), but if your gear is further away from that, you should look into an actual S/PDIF cable as they are actually different than a normal RCA cable you'd use on your stereo.

[WRETAUDIO]

SPDIF can only support sample rates as high as 48K and bit depth of 24.

[stoneinapond]

SPDIF can only support sample rates as high as 48K and bit depth of 24.

From Digidesign:

Supported Sample Rates: 44.1, 48, 88.2, 96 kHz
Maximum Word Length: 24-bit
S/PDIF: 2-channel optical or RCA jack pair
Digital Optical: TOSLINK ( ADAT, max 48 kHz sample rate )
Word Clock: Two BNC jacks
Host Connection: Two IEEE-1394a (FireWire) ports (6-pin-to-6-pin FireWire cable included)
MIDI: 5-pin MIDI DIN connectors - one input, two outputs

I think you are confusing the two formats.

[stoneinapond]

Hello all,

I have been suddenly unable to get a good S/PDIF output signal from my 002 using the configuration in my signature (intel mac, PtLE 7.1.1 cs2).

The problem exists on new sessions, as well as old ones that used to work. My current sessions are at an 88.2 sample rate and 24 bit.

I have run RCA cables to my Rosetta 200 S/PDIF in and my JBL LSR 4328 S/PDIF in, and neither can lock.

I've checked the cable by routing the Rosetta S/PDIF out to the Rosetta S/PDIF in, and it locks fine and converts audio to digital and back perfectly.

I've trashed my Digi prefs (both on the individual hard drives, and in the system drive's Library/application support/digidesign/databases).

I double checked my I/O settings.

I've done a complete uninstall, including all plugs, and reinstalled, ran cs2, reinstalled Music production toolkit - and nothing.

Any suggestions?

Sincerely,
David

Could you please be very specific about your S/PDIF routing. Also, is the Rosetta a new addition?

[WRETAUDIO]

I know for a fact that SPDIF and TosLink can only support up to 48K sample rates and 24 bit audio. Toslink is the optical version of SPDIF. Other than that, they are the same. ADAT is the optical format that can send higher sample rates and bit depths.
I did a term paper on SPDIF and Toslink in college so I'm pretty sure I know those formats.

Your hardware may not be able to send higher than 48K through the ADAT optical connection even though the ADAT standard can allow for that, but it is impossible to send anything higher than 48K through any SPDIF and TosLink connection because that is as high as that standard will go.

[WRETAUDIO]

For more info: http://www.wavefrontsemi.com/UserFil...ddendum1.0.pdf

And here SPDIF:
Audio format : linear 16 bit default, up to 24 bit expandable
Allowed sampling frequencies (Fs) of the audio:
44.1kHz from CD
48 kHz from DAT
32 kHz from DSR
Signal bitrate is 2.8Mhz (Fs=44.1kHz), 2Mhz (Fs=32kHz) and 3.1Mhz (Fs=48kHz).
Physical connection:
Cable: 75ohm +/-5% (l<10m) or 75ohm +/-35% (l>10m)

The interface
IEC958 is a newer standard which supersedes AES/EBU and also S-PDIF. The S/PDIF interface (IEC-958) is a 'consumer' version of the AES/EBU-interface. The two formats are quite compatible with each other, differing only in the subcode information and connector. The professional format subcode contains ASCII strings for source and destination identification, whereas the commercial format carries the SCMS.

Here is a short comparision table of AES/EBU and S/PDIF interfaces:

AES/EBU S/PDIF (IEC-958)

Cabling 110 ohm shileded TP 75 ohm coaxial or fiber
Connector 3-pin XLR RCA (or BNC)
Signal level 3..10V 0.5..1V
Modulation biphase-mark-code biphase-mark-code
Subcode information ASCII ID text SCMS copy protection info
Max. Resolution 24 bits 20 bits (24 bit optional)

[stoneinapond]

I know for a fact that SPDIF and TosLink can only support up to 48K sample rates and 24 bit audio. Toslink is the optical version of SPDIF. Other than that, they are the same. ADAT is the optical format that can send higher sample rates and bit depths.
I did a term paper on SPDIF and Toslink in college so I'm pretty sure I know those formats.

Your hardware may not be able to send higher than 48K through the ADAT optical connection even though the ADAT standard can allow for that, but it is impossible to send anything higher than 48K through any SPDIF and TosLink connection because that is as high as that standard will go.

OK. Let's clear the fog here.

S/PDIF is a digital audio standard for communicating between various devices in the digital domain. It has much in common with AES/EBU, but includes the provision for copy protection flagging amongst other things.

There are two methods for sending the data. Optical and electrical. Optical utilizes TOSlink connectors and uses light bursts, while the other uses RCA coaxial connectors, or BNC connectors, and uses electric pulses to send the data.

ADAT is a proprietary version of optical transmission (Lightpipe) that in its original format could transmit eight channels of digital audio at either 44.1 or 48kHz only. A later implementation of the format, called S/MUX, used multiple streams (connectors) of Lightpipe to carry higher sample rates.

Now that we have our terminology straight, let me point you to Digidesign's own specification (as I have already done) and to many other manufacturers of digital audio interfaces, that allow for 24-bit/96kHz transmission of S/PDIF, via both coaxial and optical.

Out of respect for Digidesign's forum, I have not included any links to rival manufacturer's site. Since you state you were in college, I'm sure you can find those by yourself without much effort. I would also suggest that at the end of your research, you should communicate with your teacher and have him/her update their knowledge.

[rwhitney]

I'm now entering my 23rd year working in academia, and have benefitted greatly from the position that there ARE no facts, just opinions. When in doubt (and we should nearly always be in doubt in academia, it seems) one should attribute all ideas to someone else, thus shifting the blame if we're wrong. For example, "I think S/PDIF is limited to..." or "isn't S/PDIF limited to...?" guards against the unexpected objection. Thereafter, "according to so-and-so, S/PDIF is limited..." (checking your source first, if possible) is the counter. If you don't have an "according to...", drop it for the time being.

But seriously, I have the same problem with my 003. No higher SRs out the coaxial S/PDIF. What up with that? And why no Core Audio driver to allow the OS to access the 003's S/PDIF out? Or has this been fixed somewhere I haven't seen?

[WRETAUDIO]

Please point me to the spec that states that you can transmit higher than 24/48K through SPDIF.
I would be very interested to see that.