One problem is that not all micro-leaks make a sound ...

so even an Andrea is not "infallible" -- I was inspired however, so I'm working on an electronic solution/aid -
It's basically just a small stereo headphone amplifier with an input jack for my very old Sony stereo Mic (From a long defunct "Walkman Pro"

) But I will try to add some sort of circuitry that adds a high frequency (ultrasonic) input as well .. it should be possible to do a "frequency divider" to be able to hear the higher freqs, and mix them with the ordinary audible ones.. The problem old gits have is a lack of sensitivity to high frequencies.. Andreas ears can detect up to 19 KHz .. my ears stop at 12 - 13 KHz (and that's very good for someone my age and hobbies!!)
The nose-cone looks Awesome!! Good job there!! I want to make one now for my Agusta --
"Sapere Aude"... Dare to KNOW!
The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...
103% of all people do not understand statistics...
Do not adjust our mind, theres a fault in reality :-)