Hi all !
Can anyone help me to resolve an issue during a flying lesson : a passenger kindly recorded the pilot’s instructions, but unfortunately the engine noise covers his words.
How Audacity could reduce the engine noise and/or increase the volume of instructor’s words ? Is there any available solution ?
Hereafter is a very short extract (and the plane is not yet in the air !)
I got a passable Noise Reduction to work on your supplied clip, but I don’t speak French, so I can’t tell if I did a good enough job or not. That’s on another machine, so it will take a bit to post it. If it is barely usable, then it means nothing because I know what happens to small airplane noises when they lift off. Plus, due to a quirk in how Noise Reduction works, you need to re-sample and re-apply it every time the engine changes speed. It’s about as far from convenient as you can get.
Noise Reduction works in two passes. In the first pass, Profile, you drag-select a portion of the show that’s noise-only. That’s to give the tool a taste or smell of what you want it to do. The second pass is where you turn it loose to attack that exact noise in the rest of the show. If the noise changes between step one and step two, the tool is trying to attack the wrong noise.
Even worse, if you can’t tell when someone is speaking, you can’t tell what portion of the track to sniff. If you select any voice in the sample (Profile) by accident, the tool will happily delete the voice, too.
So I’m going with No Hope. Aviation Microphones are uncomfortable and jammed in your face for a reason.
I have TP7 and TP8 Olympus microphones designed to record telephone calls. They fit in my ear and use bone conduction to record my voice and the earpiece to record the far side.
http://kozco.com/tech/audacity/clips/TP7SoundTest1.wav
http://kozco.com/tech/audacity/clips/TP7SoundTest2.wav
You slide one of those between your ear and the aviation headset. Works with a laptop or stand-alone recorder. That would have worked (now that it’s too late).
Koz
Many thanks for your answer.
Finally, I applied a solution I found on the forum… and which by the way is of your own 
: “The only worx-every-time filter we have is Effect > Equalization and select the telephone preset (attached). That strips away the low pitch and high pitch tones and hopefully, what’s left is enough.” [https://forum.audacityteam.org/t/noise-reduction-in-poor-quality-audio-recording/42783/2 ]. The result is good enough for me, as I am not an expert-of-the-art !
Best regards.