[Wanntrepreneur]

I bought an aviation headset from China that works great until you plug in an aux source such as music from an iPhone / iPod / iPad.

The airplane has built in intercom, auto-squelch, audio panel, etc.. Normally, I just talk and the microphone picks up my voice and I hear myself in my headsets and my co-pilot hears me. (For the aviation people: This was tested in a Glass cockpit, TAA, almost new airplane, PC12NG with Honeywell avionics.)

This headset has an in-line volume control and on the side of the volume control box is a 3.5mm input jack. When I plug in a cord from my phone or iPad into this box to listen to music, the intercom volume immediately drops volume and the microphone quits picking my voice up unless I bring it to touching my lips and talk very loudly into it. I would think that a music input on the headset would not affect the microphone or intercom at all.

I have headsets that are a lot more expensive that don't have this problem, so I know it must be from poor design but I would love to make these headsets work because they are very comfortable and very affordable in relation to the Bose and Lightspeed brand headsets.

The chinese guy tells me to turn the music down. Well I turned the volume all the way down and didn't fix the intercom / microphone problem at all. Even pausing the music doesn't work. The only way to get back to normal is to unplug the music cable (from either end). As soon as the cable is plugged in at both ends the problem starts, regardless if music is playing or not.

The chinese guy told me to add resistors in the music cable and if that fixes the problem then he would redesign the circuit board with the resistors in them.

I just don't think that's the problem. Wouldn't adding resistors do the same thing as turning the music volume down? I know I don't know what I'm talking about lol, which is why I'm here to ask your help. So here's my questions:

1) Any chance resistors in the music line will help?
2) Any idea what the specific problem is?
3) If I decided to put my own electronics / circuit boards in these, would I have to hire an EE to design the circuit board or is there already designed circuit boards out there that I can just buy or copy?

Oh and the aux cable that was originally provided along with the headset has 3 rings (4 connections) so I'm assuming the headset is designed to be able to make phone calls with too. It seems to me that there's not proper isolation of circuits or something, again I don't know enough to know what I'm talking about but the word isolation keeps coming to mind. Shouldn't the aux input somehow be isolated from the intercom system?

Thanks a bunch

[ebaines]

Please clarify a few things. This "box" that you're referring two has an input from the plane's communication systems and an auxillary 3.5mm input jack, and the intent is that you should be able to listen to both sources at the same time? Is the music supposed to cut off when a transmission is received on the radio, and/or when you are talking? Have you tried this with other music sources other than Apple products? Finally, what kind of cord are you using to connect your iPhone to the box?

[Stratmando]

Google "3.5 mm jack microphone splitter" may? Be what you need?