Latency, sometimes termed 'lag' creates problems of synchronisation in live online performance. A delay of as little as 10ms will cause disruption and a feeling that performers are not 'in sync' with one another or 'in time' (according to William Duckworth in *Virtual Music*) - and the time it takes for a signal to get from one performer's computer to another's may be much longer. For example, the delay between London and Oslo in September 2021 was around 40ms - 4 times the minimum that will disrupt synchronisation.
Latency is affected by several factors:
- geographical distance
- quality of connection
- amount of data being sent and received
- how many other people are using the internet at the same time
The lag fluctuates as these factors vary - usually not by much though, and it's not predictable.
However, the closer geographically your performers are to one another, the less latency you'll experience in general.
The best way to approach latency though is to never assume it can be under 10ms - even with a good connection between performers who are geographically close to one another, there can be disruptions and drop-outs. It is also important to acknowledge that the experience of latency is different for every member of the group
- Work with structures that do not require precise synchronisation either of visuals or sound (e.g. timed blocks of material)
- Use an external timer to synchronise start times and some sort of timed score or source to minimise deviations.