When you make a video call, your computer captures the sound and image, and encodes them, effectively wrapping them up in separate parcels. Each parcel contains a certain amount of the call (say, five seconds of audio or video). It then sends the parcels, independent of one another, along two separate streams of information, to an internet server (like an operator in a telephone exchange). In turn, the server sends them to the receiving computer, which decodes sound and image separately, and puts them back together again. This happens repeatedly during your call, and all being well the five-second parcels are placed back to back, making for a smooth stream of information. Of course, the same goes for the information coming from that other device to your computer, so actually, there are twice as many streams and parcels involved.
Audio files are large, but video files are massive, so the reassembly happens at different rates. In fact, if you watch closely, you’ll see that the picture and the sound don't match up exactly in a video call. The delay between them is caused by latency, which is the name for the time it takes for data to pass between a computer and the internet server. It's difficult to conceive, but because of this delay, actually the people in a video call are interacting in the present with what each other did just a moment or so in the past. Effectively, each person in a video call is in their own micro-time zone.
Latency can vary according to the equipment, the strength of the internet connection, the bandwidth of the wifi and so on, but generally, synchronisation is tight enough to enable effective music teaching. There are certain restrictions on what is and isn’t possible online, however. In particular, latency has implications for two fundamental teacher-student modes of interaction: playing together, and conversation.
Playing together: accompaniments and metronomes
The time delay makes it impossible for musicians to play together online: the sound coming through the speakers was actually made a moment or so in the past, and any sound you make will reach the other person in the future, making it impossible to be in sync with one another. Besides, lots of video-conferencing software blocks the audio when more than one person makes sound, so it is literally impossible to play at the same time as each other, never mind ‘playing together’.
The only way a student can play with accompaniment in an online lesson is using a recording of the accompaniment in their room, rather than their teacher’s. In terms of the video call, this means that the melody and accompaniment travel together between the computers/devices, in one direction. Thus the time lag will not be a problem: the total sound will arrive with the teacher at the same time (just a moment or so after it has been made by the student).
For the same reason, if a metronome is being used in a lesson, it must be in the students’ room, not the teacher’s. Similarly, counting in must be done by the student, not the teacher – this is a good habit, anyway.
The online medium influences the conversation of any video conferencing call, not just music lessons. In an ‘offline’ conversation, visual and gestural cues like nods of approval and hand gestures are exchanged as well as words; there are also aural cues, such as sympathetic ‘Mmms’ or ‘uh-huhs’, that would normally invite the speaker to continue. These cues are an integral part of the communicative exchange. By contrast, in an online conversation, the size and scale of the screen and the 2-D image mean that visual cues can be either unseen or ineffective; and the time delay obstructs the immediacy of the aural cues, making them more interruptive than interactive, to the extent that it is difficult for the person speaking to continue.
In most video calls, people adjust quickly and intuitively to the online environment adjusting their behavior without thinking. This enables the conversation to flow as best it can, such is the unconscious drive to make interactions meaningful. In online music lessons, too, adaptation is intuitive and instantaneous. However, it is worthwhile considering the implications of all this, because flow is so essential to music. In a conventional lesson, teachers might talk or play at the same time as their student, to direct them or give them a model. To do this online is to interrupt, rather than guide the performance, however, and with too many stoppages, the experience will be frustrating and demotivating. Conversely, sometimes it is difficult to stop students from playing, as they may not be able to hear their computer over the sound of their own playing.
Teaching online intensifies the need to avoid ambiguity of instruction, given all of the obstacles to communication. it is important that students are allowed to play uninterrupted, for as long as their teacher deems it valuable. This heightens the need for super-clear instructions, and teachers should consider cognitive load even more than in a conventional lesson. It is good practice, therefore, to focus on expressing instructions very clearly, in short, self-contained sentences. Mostly, this happens without any thought, because of the constraints placed on communication by the online environment. But to begin with, less obvious things and emphases may occur by thinking through lessons step by step, and post-lesson reflection. A good tip, for example is to be very clear about where students should stop playing – this will both focus attention and prevent the teacher from having to wave their arms wildly at the screen to try and get attention!
Consciously articulating the lesson structure is important too. Just as in a conventional lesson, this will break the time up, so that there is some relief from intensely focused work for both students and teachers. Offline, this is easily achieved – at the most basic level, simply by opening a different book. Online, all the information comes from a single computer screen and speakers, so varying the mode of communication helps to break things up. This can be done using resources such as theory/aural or scales apps; deliberately switching the visual medium (for example using split-screen for part of the lesson, or screen sharing a pdf of the sheet music); or using the text/chat function, which most software will have inbuilt as a pop-up feature. This last one has the advantage that in some software the content of the chat can be saved at the end of the lesson, so that students and parents/carers automatically have a record of what was covered.
So much of online teaching is the stuff of offline teaching, but in making the shift online it is worth reflecting on the medium and the delay experienced through latency, so that you can work around restrictions and use technology to enrich your teaching practice by making better use of the technology.