What is S/PDIF

But am I correct in assuming that in real world applications that spdif is mostly RCA and ADAT is mostly only toslink?

SPDIF was on both coax/RCA and TOSLINK before ADAT came along. RCA can only do SPDIF while TOSLINK can carry either. It's pretty common for gear with Lightpipe connection to be able to do SPDIF through the same connector.
 
Ooo! It does have its uses!

I can dupe stuff from a Freeview reciever to Minidisc and not have to worry about levels.

I have another MD in the "studio" that feeds a 2496 in a PC. Yup, MDs are all optical AFAIK but you can get a converter for a tenner (or build them. Just a chip driving a LED or a phototransistor driving a chip!).

Most PCI sound cards have S/PDIF so if you have a suitable box* you can run 4 channels.
Many synths have a digiout, frees up some analogue and again, no level worries.

It is pretty obvious that optical S/PDIF fixes hum loops but because of the way it is implemented so does co-ax.

*The venerable Fast track pro is one of few AI's that can run as a standalone D/A,A/D converter, just needs 9volts.

There is a trend to leave S/PDIF and MIDI off newer AIs. This is pennypinching. I ALWAYS moan about it!!
See the new MOTU baby. Digital OUT only!...STOOPID!

Dave.
 
I'm pretty sure you can use spdif out to carry an AC3 audio signal too, which can be decoded for dolby 5.1.

I used to have a dolby set up in my room and I'm nearly certain it was the spdif out I used.
 
I'm pretty sure you can use spdif out to carry an AC3 audio signal too, which can be decoded for dolby 5.1.

I used to have a dolby set up in my room and I'm nearly certain it was the spdif out I used.

You can send AC3 (and I think DTS as well) over coax, but then it's AC3 or DTS and not SPDIF. SPDIF and AC3 refer to the signal format, not the coaxial cable/RCA connector. I'm pretty sure all three can also go over optical. Normally for coax digital you should use RF grade cable, like what you'd use for video on RCA connectors, but often standard audio grade cable works.
 
Fair enough BSG; worth clarifying.

I think S/PDIF is a protocol, capable of carrying various digital formats,
so you send two channel PCM over spdif, ac3 over spdif, or DTS over spdif.

I don't think the term spdif is tied to a particular format, but I'm not an expert on it.

I have it pictured like USB. The connector can change, and the media being sent can change, but the transfer protocol stays the same.

Either way, the output that manufacturers label 'spdif out' can often be used for ac3 encoded streams.
 
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I don't think S/PDIF is inefficient, just don't get your sample rates and bit depth crossed up or you won't get the result you are looking for. On interfaces that have S/PDIF it is a way to avoid using a DA/AD path when using outboard devices that accept S/PDIF. In that regard it is more efficient than using audio I/O, plus it frees up audio I/O you would be using for FX, and bypasses the A/D-D/A converters on the outboard device which may not be as good as the ones in your interface.
 
It's the other way around though, right? It bypasses the interfaces conversion to digital(in), or analog(out).

It should bypass the converters on the interface and the outboard device because the entire signal path is DIGITAL already.

That's why you need to pay attention to the sample rate/bit depth on both devices and make sure they match up before you try to pass signal. Maybe not all devices lock up when they receive mismatched data streams but in my case I had to call Lexicon to get the factory reset procedure as they stupidly left it out of the manual. The Lynx didn't have a problem but the MPX-1 sure did.
 
Fair enough BSG; worth clarifying.

I think S/PDIF is a protocol, capable of carrying various digital formats,
so you send two channel PCM over spdif, ac3 over spdif, or DTS over spdif.

I don't think the term spdif is tied to a particular format, but I'm not an expert on it.

I have it pictured like USB. The connector can change, and the media being sent can change, but the transfer protocol stays the same.

Either way, the output that manufacturers label 'spdif out' can often be used for ac3 encoded streams.

SPDIF is the signal format and the physical interconnection, but other formats use the same connections so it can be confusing. In the beginning there was only SPDIF so all related connectors got called SPDIF. Then other formats came along and made use of the existing connectors, weakening the direct association between SPDIF and its physical interconnects, but the name still gets used.

When working with others I tend to refer to the signal type and connector type separately to avoid confusion unless the format specifies the connector. So with SPDIF I'll specify coax or optical until I know it's understood by all involved. Lightpipe only goes over optical so you don't need to specify.
 
Then other formats came along and made use of the existing connectors, weakening the direct association between SPDIF and its physical interconnects, but the name still gets used.

True enough, but they do embed dts or ac3 within an spdif signal. It's made to comply.
I take your point though; There's definitely room for confusion.
Cheers.
 
S/PDIF (Sony / Philips Digital Interconnect Format) is a type of digital audio interconnect cable used in consumer audio equipment to output audio over reasonably short distances. The signal is transmitted over either a coaxial cable with RCA connectors or a fibre optic cable with TOSLINK connectors. S/PDIF interconnects components in home theatres and other digital high fidelity systems. S/PDIF is based on the professional AES3 interconnect standard.[1] S/PDIF can carry two channels of PCM audio or a multi-channel compressed surround sound format such as Dolby Digital or DTS.
 
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spdif only uses the RCA connectors.

DVI-HDMI.jpg
 
Wikipedia said:
S/PDIF (Sony / Philips Digital Interconnect Format) is a type of digital audio interconnect cable used in consumer audio equipment to output audio over reasonably short distances. The signal is transmitted over either a coaxial cable with RCA connectors or a fibre optic cable with TOSLINK connectors. S/PDIF interconnects components in home theatres and other digital high fidelity systems. S/PDIF is based on the professional AES3 interconnect standard.[1] S/PDIF can carry two channels of PCM audio or a multi-channel compressed surround sound format such as Dolby Digital or DTS.

Fixed it for you.
 
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