The acoustic signal generator is an integral functional subsystem of the electronic variometer and is directly coupled to the real-time vertical speed and speed-command processing chain. Its primary purpose is to offload visual attention by providing continuous auditory feedback, enabling uninterrupted external lookout and traffic awareness. In the Pur version, the audio engine supports multi-spectrum tone generation with independent control of fundamental frequency, harmonic content, modulation envelope, and inter-tone timing. Climb, sink, and speed-command states are encoded through defined variations in pitch, repetition rate, duty cycle, and secondary tone components, allowing unambiguous state discrimination across the full operating range. Audio output is either from integrated rear-mounted transducer or to an external speaker, ensuring adequate sound levels and intelligibility under varying cockpit noise conditions.
V-Tone at Sink #
[Enable]
[Disable]
Decide if audio shall be mute or not when you are in a sink.
Default Volume #
25%
In this setting, the volume that is used after switching on the device is configured. The default is 25% volume.
Alarm Volume Raise #
40%
In this setting, the volume that is used for alarms e.g. FLARM traffic alarms, stall warning, etc. is configured. The default is 40% and can be raised to any value.
Stall Warning #
[Disable] [Enable]
Options to enable acoustic stall warning.
Split Volume #
[Disable] [Enable]
Options to maintain an individual volume level in Cruise or in Vario mode. By default this feature is enabled.
With this feature, which adjusts the volume separately in Vario mode and in speed-to-fly mode, the volume can be adjusted to the different acoustics in the cockpit when circling and in fast flight. In older gliders flying at high speed, a higher volume is often necessary so that the sound can still be heard. The feature takes some getting used to and is switched off by default. With [Enable] it is activated.
Cruise Audio #
[Speed2Fly] [Vario]
This setting is used to select which sound signal is generated in speed command mode. In the [Speed2Fly] mode, a tone is generated which signals the deviation from the speed command. If the airspeed is too high, a progressively higher, optionally interrupted tone is generated, if the airspeed is too low, a lower tone. In the [Vario] setting, the audio signal remains in the vario setting and can, for example, signal net climbing if the vario is set in “Net Mode” or “Cruise Net Mode”. For more information, see the “Vario Mode” setup.
Tone Style #
Preset scheme #
[XCVario]
[eXtended]
[Ilec]
[Westerboer]
[Zander]
[Borgelt}
[Custom]
The variometer provides a selectable set of predefined tone styles, each representing a distinct acoustic parameter set. These tone styles differ in fundamental frequency mapping, modulation depth (tone variation), pulse (chopping) characteristics, duty cycle, harmonic structure, and transition behavior between climb, sink, and neutral states. The purpose of these profiles is to replicate the characteristic sound signatures of variometers produced by various manufacturers over past decades, allowing pilots to retain familiar auditory cues and learned response patterns.
Available tone styles include XCVario, eXtended, Ilec, Westerboer, Zander, Borgelt, and Custom. While the underlying signal processing remains identical, each style applies a vendor-specific psychoacoustic tuning of frequency scaling, tone spacing, and temporal behavior. The Custom profile allows user-defined parameterization for precise adaptation to individual preferences or legacy device emulation.
CenterFreq #
500 Hz
The variometer center frequence at no climb or no S2F deviation, and can be modified in 10 Hz steps between 200 Hz and 2000 Hz. The default is 500 Hz.
Tone Variation #
2.00 fold
This parameter defines the total frequency span of the acoustic output in terms of octave range relative to the defined Center Frequency. It specifies how many octaves the tone modulation extends upward to the maximum frequency and downward to the minimum frequency. The parameter is adjustable in increments of 0.1 over a range corresponding to frequency ratios from 1.5× to 4.1×. The default setting using XCVario scheme is 2.0 fold, which, for a center frequency of 500 Hz, results in an upper frequency limit of 1000 Hz and a lower limit of 250 Hz. Excessively large values may shift parts of the acoustic signal outside the optimal response range of the loudspeaker and the most sensitive region of human hearing, potentially reducing audibility and tonal clarity.
Dual Tone #
[Disable]
[Enable]
This parameter selects the tonal generation mode of the variometer’s acoustic output. In [Disable] mode, a single fundamental frequency is emitted with periodic interruptions, resulting in a pulsed sound pattern (e.g. di di di di). In [Enable] mode, the acoustic output alternates between two distinct frequencies, producing a two-tone sequence (e.g. di da di da). The default configuration is [Disable] mode with interrupted output.
Chopping #
[Disabled]
[Vario Only]
[S2F Only]
[Vario and S2F]
When acoustic output is enabled in Vario or Speed-to-Fly (S2F) mode, positive values can be rendered with periodic short interruptions (“chopping”) of 100 ms duration. The repetition rate of these interruptions increases with the indicated vario or S2F deviation, providing an additional temporal cue proportional to the magnitude of the displayed value.
The chopping function can be configured as Disabled, applied to Vario only, to S2F only, or to Vario and S2F, with the latter being the default setting. At full-scale indication, the interruption repetition rate reaches exactly 10 Hz, while the minimum repetition rate is 1 Hz. Between these limits, the interruption frequency scales linearly with the corresponding display value.
Harmonics #
[None] – pure fundamental tone (classic XCVario sound)
[Some] – light overtones for better clarity
[More] – extended spectrum with stronger harmonics
[Sparky] – highly articulated, bright sound for maximum feedback
The Harmonics feature enhances the classic vario tone by adding controlled overtones to the base frequency. Instead of a single pure tone, the sound spectrum becomes richer and easier to interpret in noisy cockpit environments. By varying not only pitch and cadence but also timbre, small performance changes become audible faster, supporting precise flying with minimal visual attention.
Audio Response #
1.00
This parameter controls how the frequency of the audio generator responds to the climb rate. 1.00 means a linear connection. A value > 1.00 corresponds to an exponential behavior while < 1.00 is logarithmic.
Range & Deadbands #
Range #
[Fixed 5 m/s]
[Fixed 10 m/s]
[Variable (=N m/s)]
This setting controls whether the tone generator uses a fixed range ([Fix 5 m/s], [Fix 10 m/s]) or follows the current variometer range ([Variable = N m/s]). The range determines the frequencies and intervals the generator produces at minimum and maximum values, useful for weak climbs, where, for example, at 2 m/s with a scale set to 2 m/s in the variometer will sound like 5 m/s in fixed mode. Default: Fixed 5 m/s.
Range & Deadbands #
The vario deadband defines a symmetrical or asymmetrical vertical-speed interval around zero in which the acoustic output of the variometer is suppressed. Within this range, no climb or sink tones are generated. The deadband limits are configured via independent Lower (negative vertical speed) and Upper (positive vertical speed) threshold parameters. By default, the deadband is set to ±0.3 m/s. This function attenuates low-amplitude vertical-speed fluctuations caused by turbulence or sensor noise and ensures acoustic silence during ground operations, without requiring a reduction of the audio output level.
The Speed-to-Fly (S2F) function also implements a configurable deadband. By default, the deadband is set to ±10 km/h around the target speed. As long as the actual airspeed remains within this tolerance band, the S2F acoustic output is muted. The audio indication is enabled only when the deviation from the target speed exceeds the defined deadband, preventing unnecessary audio activity for minor speed variations and reducing pilot workload.
Lower Vario #
[Lower Vario] : – 0.30 m/s
Upper Vario #
[Upper Vario]: 0.30 m/s
Lower S2F #
[Lower S2F]: – 10km/h
Upper S2F #
[Upper S2F]: + 10km/h
