Considerable effort has gone into developing an audio vario tone and pattern to convey to the pilot the maximum information without being intrusive or annoying.

The climb tone consists of a series of beeps whose pitch, rate and volume increase with lift rate, the effect is somewhat musical.
The sink tone has two modes,
1. (fixed) threshold at -2.5 knots.
2. Sink tone on any negative climb rate.
Sink tone is distinct from the climb tone in that the pitch changes and the rate is constant.

The vario audio response is arranged to give the greatest resolution at the lower climb rates. At climb rates below about 2.5 knots, a change of 0.1 knot can readily be detected in the audio tone. This gives the maximum amount of Variometer information to the pilot at times when a Variometer is most important i.e when trying to recover in weak lift, or to extend a flight on winter days or during wave flights.

Audio information maximizes the pilots achieved climb rate without the need for visual reference to the Variometer for confirmation of the current climb rate.
A concise audio is essential to maximize the lookout time for the pilot.
See Utube video demo for more detail.