To answer your question it was a sound component in an actor (Helicopter). Just wanted the engine sound to change pitch with more or less load on the rotor.
In my spatialization test for 4.17 I added and empty actor to the map and added a sound component to that. Spatialization worked just fine with headphones on. However the the pitch doesn’t change anymore.
I have never got the modulation to change using a sound cue on gearvr. Only by using “Set Pitch Modulation” function for the sound component in the actor itself.