The absolutely largest mic foam muff I know off are from MicroAvionics and I do have them and I have helmet with neoprene chin guard and I use MGL V6 radios mostly in AR-1. What settings did you use? VOX, VOGAD, MIC LEVEL? I should try it. I think in front seat alone it may work but it is when the back seat near the engine gets introduced that it was trouble all the way.
Ok. Today I tried Bose A30 as well as Bose A20B headsets in our AR-1 trainer (914UL) with MGL V6 radio. I had to use 1/4" stereo to dual GA plug adapter because that is how we wire the radio in our gyroplanes.
I had to set MGL V6 settings: VOX to 9 or 10, set Mic Gain for pilot and passenger 1 to -6.0 dB, set Radio Receive (RX) volume to 22 and Intercom IC volume to 28 and used MicroAvionics helmets with visor and neoprene chin guard
<p>Tested and certified to European Airborne sports standard EN966 and carries the CE marking.</p>
It worked great. Last Bose I had tested in open cockpit were A10 and they absolutely did not work. The only problem is I need to cut a headband channel in the styrofoam inside MicroAvionics helmets somehow to make the helmet sit all the way down on my head and not kind of hang above the headset band.
Also had tried LightSpeed Zulu 2 and they had problems working. Wonder if I can try Zulu 3 now.