My back hurts! It’s a common complaint of the location recording engineer. Unlike our studio based colleagues, we carry, rig and de-rig a whole studio’s worth of equipment every time we go out to make a recording. Of course, there are lots of ways we manage the safe handling of this, but recently the common or garden “internet cable" has offered a solution to seriously lighten our load.
You’ve almost certainly handled a CAT5 or CAT6 cable (pictured below) at some point in your day-to-day life. These ethernet cables with their RJ45 connectors at either end are ubiquitous anywhere that you’ve got a wired internet connection. Now, they’ve also become an integral part of our recording rig.
Ken and I first started looking at CAT6 cables a bit differently after we admitted to each other that, when loading the van at the end of a recording, we always left the heavy and unwieldy multicore cables until last in the vain hope that the other person would deal with them first! These gigantic snakes of analogue cable were the way that we transferred the audio from the microphones on stage to the audio interfaces in our control room (usually 30-50 metres away). A single 30-metre microphone cable isn’t terribly heavy, but carry 16 of them at once and you begin to understand why a trip to the hernia clinic is often the next port of call after 25 years of lugging these beasts in and out of venues. We needed to find an easier way to transfer the audio signals on their long journey from stage to control room in venues.
Enter Dante: nothing to do with 14th century Italian epic poems, and everything to do with a digital audio network over ethernet cables!
Dante is an Audio-over-IP system developed by the Australian company Audinate, and it’s proved to be the answer to our heavy multicore problem. Audio-over-IP systems convert audio data to a form of local internet traffic which can then be sent down a good old-fashioned CAT6 cable with a networking switch or two used to connect all the Dante devices together. A single CAT6 cable is capable of carrying up to 512 channels of audio simultaneously! This means that, for a 16 microphone recording, rather than needing to lug around multicore cables that can weigh upwards of 12kg each, we can instead use a single ruggedised CAT6 cable which weighs about a quarter of that.
There were a few fundamental changes that needed to be made to the way our recording rig was put together to allow us to start working with Dante; the major difference being where in the recording venue the analogue signals from the microphones are amplified and converted to the digital domain.
In the years before we switched to Dante, our modus operandi was to run analogue connections from the stage to the control room via the aforementioned heavy multicore cables. This meant that the cables were carrying low voltage (quiet) electrical signals long distances. Once in the control room, an audio interface amplified the signal and converted it to the digital domain (1s and 0s representing the audio signals) at which point a computer reads and records the signal, allowing us to mix and manipulate the audio. A visual representation is shown in figure 1.
Fig.1 - Simplified view of a 16 mic recording using analogue multicore cable
With our Dante system, the audio interfaces have moved to the stage end of the chain, amplifying and converting the microphone signals to the digital domain before sending the data to the control room via the much lighter and less cumbersome long CAT6 cable. A visual representation of this setup is shown in figure 2.
Fig.2 - Simplified view of a 16 mic recording using Dante
Comparing the two diagrams, you can see that the connection from the stage to the control room is significantly less cumbersome in the Dante setup but there are other differences to consider. For instance, the controls for the recording level of each microphone are now on our computer screen rather than within physical touching distance, which initially took some getting used to but also gives some benefits like enabling much more accurate recall of settings within a session or even at a future date. In addition, from the comfort of our seat in front of the recording computer, we can configure the way any Dante device (mic interfaces, talkback speakers, headphone or speaker amplifiers, the recording computer etc.) connects with any other Dante device on the network.
No longer having the low voltage analogue signals running large distances from the stage to the control room also has the upside of the audio being much less susceptible to external electrical or radio frequency interference. Some years ago, for a live recording in St Alban’s Abbey, I ran a pair of analogue microphone cables the full length of the nave to capture the sound of musicians playing at the opposite end of the building from the main ensemble. I then discovered that the adjacent radiator pipe running the same distance was inadvertently acting as an antenna for Radio 5 Live, inducing that signal onto the mic cables! Moving all 75 metres of the cables 10 centimetres further away from the radiator pipes removed the cricket commentary from my offstage string quartet channels! That’s an issue we no longer need to consider thanks to Dante’s stage-side analogue to digital conversion.
The other major benefit that we’ve found is that Dante is incredibly scalable. Previous to Dante, if you wanted to add more inputs or outputs to a recording system you had to carefully consider how you would connect all the equipment together (particularly if you want more than 24 channels). With Dante, you can just keep adding additional interfaces to the network almost infinitely[1], which has allowed us to expand our rig over time and means that we can easily just hire in additional equipment for recordings with exceptionally large channel counts.
We’re also able to add channels in a more flexible manner. For instance, if I needed to run a pair of microphones to the back of St Albans Abbey again, I’d be more likely to utilise a 2-channel Dante audio interface in that location rather than needing to dedicate an entire 8 channel interface to that area of the performance space. This means, you guessed it, one less heavy box to carry. I’m sure my back will thank me!
All in all, the move to Dante, while not a cheap undertaking initially, has met our requirement of removing some of the heavier and more unwieldy parts of our recording rig and has brought with it a set of logistical and audio quality benefits that are very welcome. Dante is not the only option out there to remove the heavy multicores (e.g. Revenna, MADI-over-optical etc.) but it’s a solution that we’re very pleased with and will likely be the backbone of our recording rig for several years to come.
© 2022 Will Anderson & BMP The Sound Recording Company Ltd
[1] If you require more than 512 channels of audio you need to do some more complex network management/setup but that is beyond the scope of this article
Dante book photo by Zoya Loonohod on Unsplash
