Zoom, Latency & Live Music

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Within hours of the beginning of the first lockdown, music teachers up and down the country collectively came to realise something important about video conferencing technology: that there’s a delay / latency over the line that makes playing music live over Zoom, Microsoft Team, Skype etc pretty much impossible. Despite our best efforts, we were unable to overcome this issue because it’s an inherent part of all technology – that it takes time for signals to pass through the physical chips and cables of computer networks, and for servers and linked devices to process those signals.

You might notice when you’re just chatting on a video call that quite regularly two or more people start speaking at the same time. This makes for some social awkwardness – who should go first / should I wait for the other person to speak or just continue regardless etc? But, in music it is vital that everyone in a performance experiences, shares and collaborates within very fixed time parameters, and being just fractions of a second outside of this time reference can make a piece of music sound completely ‘out of sync’. This is why, in traditional performance, musicians are accustomed to watching one another to stay together. It’s also the primary reason why orchestras and choirs employ conductors.

So, how are those group music videos made?

Over lockdown many musical collaborations have been created using clever technology that makes it look like the performers are playing / singing together over an internet video conferencing system (I’ve made a few of them myself with my musician friends around the Skipton area). A really nice one came out over summer – a cover of the Foo Fighters song ‘Times Like These’:

The truth is, though, that everything you see and hear on this track has been recorded separately, in separate locations and at different times. Then someone has come along afterwards and put all the different pieces of video together so that they synchronise up perfectly. It takes an awful lot of time and effort to achieve this, and relies on every performance having been made to a common time frame / pulse. When I make these videos with my friends and choir members I either get everyone to play / sing to a metronome set to exactly the same pace, or else record a ‘guide track’ for the participants to listen to while they perform their part of the piece. Again, if anyone deviates from the agreed underlying timeline, then the pieces simply won’t fit together.

Then, how do music teachers work with students on Zoom?

This is a tricky one because, as I described above, it’s simply not possible for today’s technology to allow a truly live feed from a remote computer – there will always be a delay on the line, and there is no known way to counter it. The degree of latency is also inconsistent, sometimes lasting just fractions of a second, and sometimes up to 1 or 2 sections.

I accept this inherent challenge with online teaching and use a variety of techniques to get around it. Firstly, I do a lot of playing and echoing – I play something and get my students to perform it back to me. The delay still exists, and it means that it sometimes sounds a bit out of whack at my end, but because I’m compensating for the delay in my mind, the student shouldn’t notice much.

Another option is for us to ‘play together’, with me as the agreed fixed time frame: so I count in and start playing. The student plays along with me and at their end they experience the music to be in sync. At my end, I hear the student’s music slightly behind me, but I accept that this is down to the technology we’re using and continue regardless. It does mean, however, that I can’t be sure whether their timing has been accurate through the performance. It also makes it difficult for me to get a true sense of how well the student is managing, so I rely to a degree on their testimony / self-appraisal.

Avant Garde ‘Live’ Internet Performances

In an interesting twist, I read an interesting article in the Observer this morning about a group of musicians who have come up with an ingenious way of performing live together over an internet connection. As stated earlier, they can’t play fully live and together in remote locations because latency over the internet is changeable and unpredictable. But, then the folks at Radiophonic Workshop had an ingenious idea: instead of trying to work with a small and incalculable delay over multiple lines, the engineers at their studio would artificially extend the latency to a fixed period. Knowing exactly how long it would take for a signal to transmit from one musician to the other, they were then able to use come ingenious mathematics to get each performer playing in turn, and combining all the signals shortly thereafter for the feed of the final performance.

In a way, this technique is not dissimilar to the one lots of people use already, i.e. to record separate parts and then play them simultaneously. But, the difference is that it would be done extremely quickly whilst the performance is still going on in multiple locations. This means that a ‘live’ musical performance can be produced and broadcast with just a matter of seconds between the performers each playing their part and the overall edit being heard by the audience.

Time will tell whether or not it works – the first performance will go out on YouTube next Sunday (22nd November) at 8pm on the Radiophonic Workshop YouTube page, in support of Delia Derbyshire (and early electronic musician) and The Girls’ Network. I’m intrigued to find out how sounds!

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