User blog comment:Jkphantom9/RWBY clip on Lazer Team Livestream/@comment-10390252-20140622203241/@comment-4010415-20140623091146

Sometimes the low hum of Pyrrha's semblance is subtle, like in episode 8. She does it twice there. Once when her shield comes back after she cut the Death Stalker's stinger. It comes near her, and then you hear the hum as it attaches itself to her arm. The second time is when she's flying over the Death Stalker as the bridge falls apart. She calls her spear to her hand from its eye. The only reason we clearly heard it in Forever Fall Part 2 is because they were calling attention to it.

I would rewatch the video over and over to see if it does play that sound at some point, but odds are, someone else may detect it better than me. I'm not that good with low pitched noises.