What is SPDIF?

[JonathanRay]

What is SPDIF? What are the advantages of SPDIF? The Soundcraft M12 has SPDIF, how could this assist me in the future if I purchased a Digi 002R? Thanks for putting up with my questions.

[COOLCAT]

its the fiber optic.

Sony/Phillips Digital Interface...F something.

Usually helps skip a D/A conversion step.,,in a HR setup.

[JonathanRay]

I had an MBox, which had SPDIF. It was a single RCA jack. Is that digital?

[Clit Torres]

Yup it's digital. It's a coaxial SPDIF port. Just make sure you use the proper cable. And in case you were unaware, the SPDIF protocol carries two channels.

[JonathanRay]

Ah, thanks. Are the two channels left and right? How or why would I use SPDIF with an M12 and 002R?

[MrBoogie]

Originally Posted by Clit Torres

...Just make sure you use the proper cable. ....

In a pinch, I've used the video cable from an a/v cable because I was short one cable when i hooked it up. Any idea if this is asking for trouble or if I shouldn't worry? It seems to be working ok...


BTW, SPDIF is not fiber optic. It is standard cable. The fiber optic cable is called toslink.

[JonathanRay]

Does an RCA video cable contain 2 channels?

[mikedaul]

An RCA video cable will work fine for spdif. Basiclaly the thing you need to worry about is the resistance of the cable, and the video cable is the proper resistance for spdif data (75 ohms).

Typically a device will have two spdif ports, one for input and one for output. Both carry a stereo (L + R) signal. One thing you will need to worry about is making sure the clocks of your two devices are working together correctly. In general you will slave the device with the lesser clock to the device with the better clock. I would guess that the 002r would have a better clock than the spirit, but that's just a guess...

[JonathanRay]

What is a clock? What is the purpose of using SPDIF between the M12 and 002R?

[SonicAlbert]

I think the M12 has a SPDIF digital output doesn't it? If you wanted to use the converters in the M12 you would go out of it digitally. I fyou want to use the converters in the 002R, you would go out the mixer main outputs and into a pair of line inputs on the 002R.

When you have two digital devices, one sending and one receiving digital data, they have to be synchronized to work properly. The "clock" is how they do that. The receiving devices locks to the sending device. One is the master and the other the slave device.

[mikedaul]

What is the purpose of using SPDIF between the M12 and 002R?

The purpose would be that you could send a submix of all of the inputs in your m12 as a stereo pair digitally into your 002r, enabling you to record more sources at the same time (like a drumset). *I don't think in a recording situation you would get much from going out of the 002r into the m12. You could use the m12 to mixdown your songs in PT and send that mix back through the spdif to the 002r. As was mentioned, the benefits really depend on which device has the better-sounding set of a/d converters.

*One small edit - I assumed the m12 had spdif in as well as out. It doesn't, so ignore this line

[reshp1]

SPDIF is the digital format, not the specification for the cable. SPDIF can be transmitted both on RCA cables (75Ohm) AND/OR TOSlink optical cables.

[Farview]

Spdif is a digital protocol. It can be sent via a fiber optic cable or a 75 ohm cable with rca or bnc ends. spdif is just the protocol, don't confuse the type of cable with the type of signal it is carrying.

[mikedaul]

Absolutely true, but fwiw the overwhelming majority of spdif devices in the proaudio world use a coaxial interface. The only time I've ever encountered optical spdif is with minidisc and home stereo equipment. If you go to banjomart and ask for an spdif cable, my hunch is 99/100 times they will hand you a 75ohm coaxial cable with rca ends.

[Farview]

Originally Posted by mikedaul

Absolutely true, but fwiw the overwhelming majority of spdif devices in the proaudio world use a coaxial interface. The only time I've ever encountered optical spdif is with minidisc and home stereo equipment. If you go to banjomart and ask for an spdif cable, my hunch is 99/100 times they will hand you a 75ohm coaxial cable with rca ends.

Pro audio and banjomart are mutually exclusive terms

[Blue Bear Sound]

Originally Posted by Farview

Pro audio and banjomart are mutually exclusive terms

Not only that, but TOSLINK is used almost as much as Coax for S/PDIF connections on gear............

[fraserhutch]

Originally Posted by mikedaul

Absolutely true, but fwiw the overwhelming majority of spdif devices in the proaudio world use a coaxial interface. The only time I've ever encountered optical spdif is with minidisc and home stereo equipment. If you go to banjomart and ask for an spdif cable, my hunch is 99/100 times they will hand you a 75ohm coaxial cable with rca ends.

Absoutely not true. The vast majority I have seen use EITHER.

[COOLCAT]

found this definition.

S/PDIF

S/PDIF (Sony/Philips Digital Interface) is a standard audio transfer file format. It is usually found on digital audio equipment such as a DAT (Digital Audio Tape) machine or audio processing device. It allows the transfer of audio from one file to another without the conversion to and from an analog format, which could degrade the signal quality.
The most common connector used with an S/PDIF interface is the RCA connector, the same one used for consumer audio products. An optical connector is also sometimes used.


yeah TOSLINK...i forgot that term. thats the more common name for optical?

I've got fiber optic on my 2488...and noticed a big + difference using it compared to rca (d/a) on my consumer Pioneer 555 CDR.

[mikedaul]

Pro audio and banjomart are mutually exclusive terms

Lol True that, I'm just figuring that's where new-to-recording folks typically go to buy cables.

Not only that, but TOSLINK is used almost as much as Coax for S/PDIF connections on gear............

Wow, guess I'm mistaken then. But the stuff I use on a regular basis is all coaxial. Everything (at least that I've seen) by echo, m-audio, rme (although they normally allow for the adat optical to pass spdif as well), digi (the non-tdm stuff) etc is all coaxial as well. But I know you have a badass studio and probably see much more gear in a week than I've seen in a year, so I trust you. And I'll go away and keep my ignorant ass quiet now

[MrBoogie]

Originally Posted by COOLCAT

found this definition.

S/PDIF

S/PDIF (Sony/Philips Digital Interface) is a standard audio transfer file format. It is usually found on digital audio equipment such as a DAT (Digital Audio Tape) machine or audio processing device. It allows the transfer of audio from one file to another without the conversion to and from an analog format, which could degrade the signal quality.
The most common connector used with an S/PDIF interface is the RCA connector, the same one used for consumer audio products. An optical connector is also sometimes used...

I stand corrected. The website I got my information from about spdif specifically said it is a standard for digital audio transfer over a 75 ohm cable. (I really need to be more careful which websites I get my information from.)

[Richard Monroe]

"digi (the non-tdm stuff) etc is all coaxial as well"- Mikedaul Not true, Mikedaul- Digi stuff, such as 002 and 002r will transmit or receive optical S/PDIF or ADAT from the same optical I/O's. I use my 002 routinely both to send and receive optical S/PDIF to and from Roland VS1824CD and from the Joemeek twinQ.

Yo JonathonRay- Basically, you ask, what is S/PDIF good for? There are several answers:
1. It allows you to simply take advantage of more I/O's, which can often mean more channels.
2. It can allow you to bypass the cruddy A-D conversion and often, the preamps, of otherwise very good pieces of gear. For instance, I often send the signal from my Digi002 to a Roland VS1824CD, bypassing the Roland's cruddy preamps, and then taking advantage of the Roland's rather good editing and mixing capabilities. Then I send the signal back to the 002 by S/PDIF, so the Roland's A-D conversion and preamps never affect the signal.
3. By using optical S/PDIF, you can completely avoid electromagnetic interference from radio signals, power cables, computer monitors, etc.-Richie

[JonathanRay]

Thanks for all the help!

[DonaldChang]

with 1/4 cables theres like steps of quality...a 30$ mogami is better than a 10$ hosa...would this be true for S/PDIF cables since it's digital?

[mikedaul]

richard - didn't know that about the digi stuff. was just going by my experience, and the digi site only mentions coaxial:

http://www.digidesign.com/products/l...s/hardware.cfm

As for is a $10 digital cable better than a $100 one, that's a whole other debate. I say use the cheapest cable that will get the job done. Audiophiles will happily spend lots of $$ for digital cables. I'm sure there's a happy balance somewhere in between.

[COOLCAT]

there is an engineering aspect to everything.
so yes even the material used to make the coaxial, the insulation...gold plugs!
with Fiber Optic is generally the purity of the glass that would degrade the signal internally. but unless you have a High Dollar Test machine..you won't be able to see it with your eyes.

can a human hear the difference? I buy my speaker cable at Home Depot.
I can change it out whenever I like...cheaply.
I tried the Monster Cable "blindfold test"..... i couldn't justify the $$.

However, in a pro $$$ customer ready studio and especially in Live applications you would want better built stuff to withstand the physical wear and tear, the cable plugs, soldering, gold plated, gauge, radio interference.

but if something costs 10x the $$$$$$ I sure as hell better "see and hear" a difference!!