If the speaker is traveling away from you at the speed of sound, the frequency will be halved, that is, it will go down by one octave. So only the lowest bass will go out of hearing range. Also, it will be overwhelmed by the jet engine noise and will quickly fade into the distance.
Doctor t1_j1eqoqv wrote
Reply to Can the Doppler effect make sounds inaudible by shifting frequencies out of human hearing range? Or vice versa? by IonnoFry
If the speaker is traveling away from you at the speed of sound, the frequency will be halved, that is, it will go down by one octave. So only the lowest bass will go out of hearing range. Also, it will be overwhelmed by the jet engine noise and will quickly fade into the distance.