Hi all,
Funke ATR833 radio installed in a PA-17.
When using an ANR headset (Lightspeed Zulu 2 in this case) there is a phenomenal amount of noise on the microphone when it lifts. This issue ‘follows the headset’, i.e. it doesn’t matter if P1 or P2 is using it, the noisy mic is always the Zulu 2. The other headset being used is a passive David Clark.
I don’t think it’s a squelch issue. I’m able to adjust the mic squelch so that it lifts at the appropriate point (i.e. you have to actually speak to lift it, it is not lifted by ambient engine noise depending on exact mic location or the user exhaling). But when it does lift, there is such a huge quantity of noise coming over the mic that the user has to basically shout to be heard. This is the same in their headset (i.e. the sidetone) as for the other person in the cockpit.
There is no such problem using these two headsets together in my other usual ride (a TB10 with a latest-gen Garmin audio panel and radio).
Any ideas?
Hi,
could be a mic sensitivity issue. On the TB 10 you probably have individual VOX levels (intercom squelch). the built in intercom in the atr has only one for all. So to get it to work one solution could be to adjust the mic sensitivities to be approximately the same for both headsets.
just my 5 cents.
/Patrik
I have had something similar, but perhaps not exactly the same. Light Speed Zulu in a Yak. I also had problems with the squelch levels (with PM3000 intercom). I moved on from my share in the aircraft before I fully resolved the problem. In then end I think I had both mic gain problems and an issue with a ‘whistle’ through a side window or vent causing the squelch to open.
You can try the microphone gain adjustment on the Zulu to see if it helps, see the quote from the Lightspeed website below.
What is mic gain and how do I adjust it?
You can think of microphone gain as a volume control for your microphone. Soft voices might benefit from an increase in gain in order to improve audibility and, in some cases, to break squelch; louder voices may need little to no gain increase. Equipping each headset with its own gain adjustment helps balance loud and soft voices in a multi-headset environment.
To adjust mic gain, remove the foam windscreen on your microphone and then remove the small cap next to the Lightspeed logo on our microphone to reveal the adjustment dial. Turning the adjustment dial clockwise will increase gain and turning it counterclockwise will decrease gain. A little adjustment goes a long way, so move the dial in small increments (think one-hour increments on a clock face) and test it in your aircraft. When you are satisfied with the adjustment, replace the cap and foam windscreen.
Thanks guys.
I flew a little yesterday evening and experimented with the gain control on the microphone and the mic sensitivity control on the radio/intercom.
I think there’s an improvement, but it’s hard to be sure – it sounds like my voice (in the sidetone) is quieter as well as the background noise being lower. The real test will be tomorrow when I fly with my other half because it is for the other person in the aircraft that the background noise is deafening when the Zulu 2 mic lifts.
My (cynical) suspicion is that by turning down gain and sensitivity I have just reduced the level at which that mic outputs into the radio/intercom, but that the signal to noise ratio of the output remains unchanged. Thus the noise the other person hears will be reduced, but the volume of my voice will have reduced correspondingly and therefore I’ll be just as hard to hear. Still, that will be an improvement because at least the noise is not unpleasantly loud for them.
Perhaps the noise-cancelling mic on the Zulu 2 just isn’t very good at noise cancelling in very loud environment? If one removes one’s headset then the PA-17 cockpit is noticeably louder than the TB10, as one might expect.
I had exactly this issue with my LS Zulu. Turned out to be the draft from the fresh air vent. I reduced the flow from the vent and the noise stopped.
