I did very early testing with VOX on the XPR6550 and used it, very successfully, on a diesel fire engine (pumper), while sitting in a seat directly above the engine, with the engine revved up to about 2000 rpm's. The VOX worked perfectly - the noise didn't even come close to holding the PTT.
On the newest firmware versions, you can enable/disable the background audio noise suppression. Make sure that this setting is enabled.
I was using a single-earpiece headset with boom microphone. I don't remember the model number, but I can find out tomorrow. What are you using there?
I have a recording of one of the tests that I did with VOX and the fire engine. If you'd like to hear it, Private Message me and I'll give you a link.
John Rayfield, Jr. CETma
W0PM
We are using MotoTRBO in a VOX configuration in a relatively noisy environment. The problem is that when we key the VOX the background noise is sustaining it and not allowing anyone else to get through. We already have the VOX sensitivity at level 5 and other than putting it at 6, the highest setting which involves the person having to yell to loudly to talk, is there any other setting to change that could improve this? At first thought the changing the gain might be something that could help but am not clear on it. This is is a rather time critical problem which is why I am coming here first rather than spending a lot of time trying to work around it so any feedback would be awesome!