I did a search on HR and some Googling, but I still cannot figure why I could/should utilize S/PDIF on my interface for home recording. Not sure it matters, but I run Studio One for my DAW and I interface through a PreSonus 1818VSL. Anyway, I use USB for "real" audio and MIDI for, well, MIDI. I get the concept of ADAT and FireWire. But why on Earth would/should I be using S/PDIF? Thanks guys.
S/PDIF, why?
- Thread starter gregoryg
- Start date
BroKen_H
Re-member
S/PDIF is used with some (actually a lot) of home to pro grade CD/DVD/BD players (among other things). It's an optical out/in system that offers digital to digital (avoids conversions) to maintain signal integrity. For example, if you're dropping a track from your CD, you would use S/PDIF instead of having the CD convert DA and then your interface convert AD to get it into your system...of course this is not a great example, because all computers have CD players, but you get the picture.
It's basically Soyn/Phillips AES/EBU format.
It's basically Soyn/Phillips AES/EBU format.
I hear ya, and saw that in the Googling I did, I see it has a lot of implications for home theater... Still no idea how/why I would use it on my 1818VSL (or any other) interface though. Perhaps I'm thinking too small-picture here: instrument/performer > microphone/cable > 1818VSL/interface > MIDI/USB > computer/DAW. Somewhere in that equation I am missing the point of S/PDIF.
Steenamaroo
...
Hey,
It's just another option...that's all.
You can have analog inputs which go through preamps (or not) and then through converters.
Digital inputs are already digital and don't need to go through converters, so any digital input will bypass the interfaces converters.
Adat optical is a digital audio connection capable of carrying 8 channels 24bit/48khz.
S/PDIF is a stereo digital connetion. You can find it in optical format or over a plan old RCA connector.
If, for example, you had a two channel preamp with converters and an S/PDIF output, you'd just bang that straight into the S/PDIF input of your audio interface.
An interface with 8 mic preamps, adat input and s/pdif input has 18 inputs in total....whether you have the gear to make use of them or not is a different story.
The main reasons for using adat or s/pdif are that they let you have more simultaneous IO, and they all you to use third party converters which may, or may not, be of better quality than the ones offered to the preamps on your interface.
Tadpui
Well-known member
On an audio interface, it's a way to hook up a couple more channels of digital input/output. For instance, there are stand-alone preamps that have S/PDIF outputs on them. The ADC is done on the preamp and sent to the interface with no further conversions necessary. It's just a way to expand the number of channels you have on your interface.
OK cool so if for example I am using all 8 XLRs say for example:
1 - Left OH
2 - Right OH
3 - Kick
4 - Snare
5 - Tom 1
6 - Tom 2
7 - Tom 3
8 - Tom 4
And so if I wanted to also use a digital drum, like say an Alesis Perc-Pad, as input 9 I could run that IN S/PDIF? Not at home now to check, but I assume the DAW would then recognize that via the USB connection as a 9th input? Can't imagine running USB out and S/PDIF out simultaneously, so I guess it would "have to" see this as a sep. 9th input run back out over the USB signal?
1 - Left OH
2 - Right OH
3 - Kick
4 - Snare
5 - Tom 1
6 - Tom 2
7 - Tom 3
8 - Tom 4
And so if I wanted to also use a digital drum, like say an Alesis Perc-Pad, as input 9 I could run that IN S/PDIF? Not at home now to check, but I assume the DAW would then recognize that via the USB connection as a 9th input? Can't imagine running USB out and S/PDIF out simultaneously, so I guess it would "have to" see this as a sep. 9th input run back out over the USB signal?
Steenamaroo
...
No man, I'm not sure you're getting it.
USB/Firewire/PCI/Thunderbolt is the way your audio interface talks to your computer.
It doesn't relate to analog audio or digital audio formats at all.
Your computer sees an audio interface (via usb) which has the following inputs ports available.
8 analog inputs (mic preamps - 8 physical connectors)
8 channels of digital input over adat (one physical connector)
2 channels of digital input over spdif (one physical connector)
The computer doesn't care what kind of format or connection you're using to get the audio to the interface.
The computer just sees input 1 or input 9, or whatever.
If that happens to be analog of spdif, it doesn't matter.
Now, what does matter is that adat and spdif, being digital audio formats, require the source device to have that format of output available.
Think of it like the audio is transferred via code, yeah?
To use an spdif input you have to have a device which sports an spdif output.
The reason I suggested a two channel interface as an example is because spdif carries two channels of digital audio.
Your computer will see it as input 9+10, or input 17+18. (not certain which)
The same applies to adat. If you bought an ada8000, you could plug 8 mics into it and run an adat cable from it to your interface.
Your recording software will now have access to 16 channels with mic preamps..See?
The built in preamps will be listed as 1-8 and the ada8000 ones will probably be listed as 9-16 or 11-18. (again, not certain which)
Even right now with nothing plugged in, your recording software should tell you you have 18 input paths.
Is this making sense at all?
Kinda sorta but not really. I am going to need to be at home to try it and see what the computer sees. I guess what I wonder is, is this (below) an AND situation or an OR situation?
8 analog inputs (mic preamps)
8 balanced line outputs
8 channels of digital input over adat
AND
2 channels of stereo digital input over spdif -- SIMULTANEOUSLY?
OR
8 analog inputs (mic preamps)
8 balanced line outputs
8 channels of digital input over adat
OR
2 channels of stereo digital input over spdif - CAN HAVE ONE BUT NOT ALL
As in, can I run in all 8 XLR + S/PDIF and then ALL out via USB?
Steenamaroo
...
All of those inputs are available simultaneously.
Simply, you have an 18 input interface.
8 of those inputs have converters and preamps available.
10 of them don't. You have to bring your own converters and preamps via adat (8 channels) and spdif (2 channels), if you want to plug mics in to them.
Your drum hardware doesn't really factor in because you'd either record midi data from it, or stereo analog output.
Simply, you have an 18 input interface.
8 of those inputs have converters and preamps available.
10 of them don't. You have to bring your own converters and preamps via adat (8 channels) and spdif (2 channels), if you want to plug mics in to them.
Your drum hardware doesn't really factor in because you'd either record midi data from it, or stereo analog output.
bouldersoundguy
Well-known member
S/PDIF is left over from the days when digital transfers could only be done in real time, like playing a CD through an S/PDIF equipped receiver, or copying a CD to a digital cassette recorder (there were such things).
Now it's mostly just a cheap way to make an interface expandable to more inputs. Connect a S/PDIF equipped mic preamp to it.
Now it's mostly just a cheap way to make an interface expandable to more inputs. Connect a S/PDIF equipped mic preamp to it.