Why VOX is reliable when using Autocom.
VOX isn't unreliable at all on a bike with a noise cancelling microphone and BGNS (Background Noise Sensor) - this is a mic mounted SEPARATELY from the main mic., mounted within the helmet.
It 'listens' to the noise from the helmet and increases the VOX trigger level as the noise (in the helmet) increases. That said, the BGNS is not necessary to create the Noise Cancelling mic they provide. It's an add-on for the higher quality units they provide / I use for Bike Instruction. The same mic influences music volume, as the noise in the helmet / speed increases. As you slow down, the volume is decreased.
My trainees regularly tell me that they find the system amazing, as they can't hear anything, other than my voice. It's the same with the phone - bluetoothed via the Garmin SatNav. Those I choose to take a call from, state they don't believe I'm on my bike at the time - there's no other noise evident. The systems used by bike-to-bike and Instructors, where noise is an issue, is the more entry level end of the market / cheaper units. A system from the likes of Autocom provides Noise Cancelling Microphones.
Mike Bentley RIDEcraft (UK) Ltd.