How noisy/quiet is it?

• Spectrum has quiet modes. For interviews, keeping the rig in quiet modes prevents lav mics and shotgun mics from picking up motor noise. - Here's a professional interview from one of our customers, Phil Keoghan with Laird Hamilton - the spectrum was used for the cut in movement shots - https://www.youtube.com/watch?v=6UMN0tTtMmI
• In other modes, we allow the motors to make noise.  Profiles like "Fastest" or "Timelapse" let the motors make noise and the motors are audible, but can move faster with heavier loads. Typically these modes do not require audio capture.

Why not just make everything quiet? 
Driving the motor and letting them make noise not only allows for faster speeds and higher torques, they are slightly more efficient.   If you are shooting VFX where noise isn't captured, let it make noise.  If you are shooting timelapse with portable power, push that battery pack to run longer!