What causes weird cracking/popping sound when playing 3d sound

I've tried spawning it further ahead of the camera, and it still does it. It shouldn't be playing the sound twice because the audio source is on the missile, and there is only one missile being fired at a time (using Play(), not PlayOneShot())

I think it might be clipping too, e.g. unity's spatial audio system is boosting is volume for closeness. But there needs to be a way to set the max volume on it so it doesn't go over the clipping level.

Right now as a workaround I am fading in all of my spatial sounds for the first second of playing to avoid the clipping noise. It's ok for bullet engine noises and stuff but making the timing of the sound look delayed when used with explosions.

have you tried to instantiate the source first then add the clip to the source after its been created then making it play and not play on awake? maybe nute volume of source when no clip is active and restore it once a clip isPlaying. this could all be removed again, its to see if the clip or the source is the cause of the unwanted sound.