How to get 18 inputs with an 001/002/002r/003/003r?

All three of the digidesign multiple input interfaces for LE, the 001, 002, and 002r, come complete with 8 analog inputs, 8 digital inputs via ADAT lightpipe, and 2 digital inpuits via S/PDIF. To take advantage of these digital inputs, you will need to purchase digital converter units; one unit with 8 channel lightpipe output, and one unit with 2 channel S/PDIF output. Keep in mind, all three units must use a single clock source to be able to use all 18 inputs simultaneously.

Some popular 8 channel units for the lightpipe inputs include:

Some popular units for the S/PDIF inputs include:

Connecting it all

Depending on what devices you have chosen, and whether or not you are using them for input only, or input and output, your setup may differ slightly from what I am about to describe. I am descibing full connections on both units using non-specific hardware examples, so keep that in mind. Your setup may differ slightly.

S/PDIF

The connection is pretty basic; out to in and in to out. You will need 75ohm RCA cables to make the connections. These are co-axial cables that differ from the basic home-stereo type of RCA cables, and it is very important that you use the proper cables.

You would connect the S/PDIF output of the external device, to the S/PDIF input of the Digidesign hardware, and the S/PDIF output of the Digidesign hardware to the S/PDIF input of the extenal device.

ADAT

The connection, again, is pretty basic; out to in and in to out. You will need standard lightpipe cables to make the connections.

You would connect the ADAT output of the external device, to the ADAT input of the Digidesign hardware, and the ADAT output of the Digidesign hardware to the ADAT input of the extenal device.

Clock Settings

This is usually where most people go wrong with this setup. In the digital audio world, it is very important that you only use one digital clock. For this setup, we will have 3 digital clocks connected together, and if we try and record without setting up the system to use only one of those clocks, we will get glitches in the audio in the form of pops and clicks because the digital clocks are not in sync. The tricky part is “Which clock to use?”, but that’s really up to you to decide with the particular hardware that you have chosen. For instance, if you have chosen a higher quality interface for S/PDIF, such as the Apogee Rosetta, but you’re using the Behringer ADA8000 for ADAT, you will probably want to choose the Rosetta as your master clock.

This is where experimentation with your particular system would need to take place, to determine what works for you. However, lets talk about how it’s done so that you know what you’re looking for.

It’s important to note here that when creating a session to use in this manner, you absolutely make sure that you create it at the target sample rate. If you create a session at 44.1kHz and then clock to 48kHz there will be problems. If you create a session at 48kHz and then clock to 44.1kHz there will be problems.
It’s also important to note that due to limitations of the ADAT transfer format, you will not be able to us a sample rate higher than 48kHz using this method.

In Pro Tools, go to Setup->Hardware and under the “Clock Source” dropdown, you would select which device you have decided to be the master clock, either ADAT or S/PDIF. Make sure the Optical input selection is set to ADAT. Now you need to make sure the external devices are clocked correctly. On the device that you have chosen to be the master clock, make sure that it’s clock is set to “internal”, and on the other device, set the clock to “external”.

Back in Pro Tools, make sure the your I/O settings are set to send and receive from the digital inputs. Go to Setup->I/O…, select the input tab and click the “Default” button. Do the same for the output tab. You can rename all of these I/O to be more descriptive if you want, either here, or by right clicking on the I/O in the main mix/edit windows.

Those are the basic steps to setting up a full 18 I/O setup with the Digidesign hardware capable of doing so. This is where the hardware specific configurations will come into play, such as “Which clock to use for master”. Some units are also “output only”, so your situation may differ from this setup just slightly. This is where this tutorial ends, as those decisions and experimentations are up to you.