I like to have at least a little bit of airplane noise in the background. So I simply put a small mike into the earcoup of my BOSE A20. This way I get a clear recording of ATC/Intercom plus the airplane noise in the background.
Thanks for posting that, petakas. I merged it into a previous thread on the same topic.
The circuit diagram appears about 1/3 into the video:
and it is just an attenuator, but the use of the 150 ohm resistor in series with the 20k ohm one is plain nonsense! The 150 ohm one will do absolutely nothing.
This came up before a few times and here is the adaptor I used (although that is for producing a “line level” to feed a suitable recorder).
I suspect the above 1500 ohm resistor is there for a purpose and the Iphone uses that value to auto detect a specific accessory.
However: in the above-linked discussion (which is not Iphone specific) there is a comment
Most phones are not capable of accepting external audio onto a video, except from their internal mike (which is obviously useless for aircraft use)
and I wonder what has changed since then? I know I did solve this at one point with a 3rd party camera app, but I think that was on the Nokias, and it never worked on the Samsung S6 or S7 which appear to have the internal mike as the only possible sound source for the factory camera app. I never bothered to investigate this further because I don’t use the phone for video recording anyway, and have a dedicated sound recorder. Presumably the Iphone has other options, unless that circuit is just for sound recording, which is a different app altogether.
