Welcome to this tutorial on connecting devices with an AES3 or SPDIF coaxial lead.

AES3 and SPDIF coaxial are the most popular professional and consumer 2 channel electrical digital interconnects. AES3 is essentially a professional version of SPDIF. Many devices feature both interconnects and for most applications there is no audible quality difference between them.

At standard sample rates, 44.1KHz and 48KHz, the PCM data transmitted by both formats is essentially identical, but the AES3 version is better protected and at a higher level, +4dBu.

Caption - Connection processes (AES3 and SPDIF coaxial signals)

Connecting devices with AES3 or SPDIF coaxial leads, requires 2 distinct processes ..

1. physically connecting the lead
2. configuring the digital synchronisation word clock, which may involve connecting a BNC word clock lead

Caption - Connecting the digital output of a pre-amp / voice channel to an audio interface with AES3 or SPDIF coaxial leads

Demonstration Follow this procedure ..

1. Turn down the monitoring system
2. Turn on the pre amp/voice channel
3. Check that phantom power is disabled on the pre amp/voice channel
4. Nominate the device which will operate as the word clock master, either the audio interface or pre amp/voice channel. If the pre amp/voice channel does not have either word clock or digital in, you will have to set it as the clock master
5. If you audio interface has a word clock or digital output and is the clock mater, and the pre amp/voice channel has a word clock or digital input and is the slave, connect a suitable digital or BNC lead from the audio interface to the pre amp/voice channel and terminate the signal as necessary - check the pre amp/voice channel manual on which BNC termination method is required, and watch our tutorial on Digital audio synchronisation for more advice
6. Connect an AES3 or SPDIF coaxial lead from the pre amp/voice channel output to the audio interface input
7. Set a DAW track to receive the signal from the pre amp/voice channel
8. Set the sample rate of the pre amp/voice channel to match that of the word clock master device
9. Set the word clock sync of the pre amp/voice channel to slave to the audio interface and check that it has locked
10. Set the i/o of the pre amp/voice channel to digital AES or SPDIF coaxial out
11. Connect a microphone to the pre amp/voice channel - see our tutorials on connecting microphones for the correct procedure
12. Whilst observing the meters on the pre amp/voice channel, audio interface and DAW track, ask your performer to start performing and raise the input gain of the pre amp/voice channel until you have a good level averaging approximately -6dB on the digital scale
13. Raise your monitoring system level

Caption - Thanks for watching

The script for this video, with accompanying images, can be found at projectstudiohandbook.com 

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