How can I make the AI jet have 3D sound?

I’m working on a game which uses the AI jet from Unity’s Standard Assets, but I find that the sounds (jet engine & flight wind) are not being handled as 3d, so no Doppler effect, no volume roll-off, just a constant level all the time, regardless of player’s proximity to the jet.
The AeroplaneAudio.cs doesn’t provide an option for 3D sound, and I don’t know how to code one in.

I tried creating an empty game object, adding an audio source component, adding a simple script to play the jet sound, and made that game object a child of the AI jet… this gave me a Doppler effect, but it bore no relation to my proximity to the jet, and the volume level was still constant regardless of proximity.

I wonder if I’m just missing something simple that isn’t obvious to this relative noob…

If anyone could lend me a clue, that would be greatly appreciated, since at present, I am entirely without clue.

OK, I found a solution.

I created an empty GameObject, attached it o the AI Jet, gave it an audio source, assigned the jet sound, set spatial blend to 3d, (leave Doppler level at 1) - but the key turns out to be changing the volume rolloff from Logorythmic Rolloff to Linear Rolloff.

Now I have a working 3d jet sound. hooray. On to the next challenge.

Find the jet’s AudioSource component and go to “doppler” and slide it all the way to the right (says 3d below the slider)