F60Pro on the TrueX - Can someone identify that motor noise - Spring has come, lets get out and play

Could someone identify the source of that motor noise??? Second drone test of the day!! [FRESH video] [REC date : 2019 MAY 02] Welcome Spring! Most colorful season of the year Let's get out and play!!! Trying to get used to my old quad after a loooong relaxation time . . . Cannot get used to my older Rate Profiles! And i thought back then that they were ideal!!! A quickie testing my Betaflight quad on 4S. I love those old F60Pro 2500KV on my 5inch TrueX frame from AstroX using HQ Props 5048x3 *NO neighbors where being annoyed during this run . . . There was noone around during this time of year The KWAD: Frame: AstroX TrueX aero FC: FlightOne Revolt V2 FW: Betaflight 3.5.1 OSD: micro minimOSD ESCs: HAKRC 35A @ DSHOT1200 Motors: T-Motor F60 Pro 2500KV @ 4S VTX: TBS Unify HV@500mw Camera: RunCam RotorRiot RC Receiver: FrSky XSR Props: HQProp 5048x3 Please show some love, support like and subscribe if you like FB: https://www.facebook.com/FPViX/ YT: https://www.youtube.com/channel/UCkdXTejvoklj7PdCszJ2GjQ Airvūz: https://www.airvuz.com/user/pathos_fpvix/videos