Comparison of remote music performance software

Software created specifically to minimise or eliminate issues with Internet-related audio latency enables musicians to perform live music together over domestic broadband connections. The use of various compression and other techniques, together with affordable low-latency audio interface hardware (which most of the systems listed here are also optimised to work with), has reached a state in which it is practical for even large numbers of musicians to play or sing together without experiencing significant problems.^[1][2][3][4]

One of the problems with music playing over the Internet in real time is latency^[5] - the time lag that occurs while audio streams travel to and from each musician. Although the precedence effect means that small delays (up to around 40 ms) can be perceived as synchronous, longer delays make it practically impossible to play live together.^[6][7] A further problem is jitter, a type of packet delay due to changes in latency over time, which results in choppy or distorted sound. Long delays can even lead to packet loss (perceived as a 'blackouts'). These can be alleviated by delay buffers or jitter buffers, but these then add to the overall round-trip delay, so need to be balanced.^[8][9]

Total latency is composed of:

• Network latency due to delays within the network - every 300km is responsible for at least 1 ms extra latency since the speed of light limits the data transport on internet.
• Conversion latency - if analog-to-digital conversion or digital-to-analog conversion is not handled by special hardware, these conversions will add additional latency;
• Audio latency from sound traveling through air, if the microphone and/or loudspeakers are not in immediate proximity. Every meter of distance adds around 3ms delay due to the limitation of the speed of sound.

Popular video conferencing software such as Zoom or Teams is unsuited to this task as the latency is too high. Zoom recommends "a latency of 150ms or less" and jitter of "40ms or less",^[10] and in some 2020 tests was shown to have an average latency of 135 ms. The "Audio poor quality metrics" for Teams include having "Round-trip time >500 ms" and "Jitter >30 ms".^[11] In addition, most such software is optimized for speech rather than music, so sustained musical notes can be misidentified as background noise and filtered out (although this can be alleviated to an extent via settings such as "Enable Original Sound"). Conferencing software is also often designed for one person to be heard at a time (the speaker gets 'focus'), to stop people talking over each other, but this makes playing music together impossible. In addition, it does not normally allow detailed setting of individual audio streams' volume or panning on the user side.^[12]

The following table compares key features of software written for the expressed purpose of allowing musicians to perform music together over the Internet. It does not attempt to cover subjective features such as sound quality or ease of use. However, some software on the list may address different aspects of remote collaboration better than others, or may be more suited to certain musical genres.