Question

A single "Pop" happens when powered on.

Answer 1

Turn them on before you start your computer,, as well , always turn on all devices prior to booting up,,,
IF they still pop when booting up, get a support ticket in,, Have tech's work with you,,

Answer 2

Mine all do the same and have for years. I wouldnt concern myself with it, unless it is so loud you fear damage. I assume it is the dsp coming online and has little to nothing to do with input signal, as mine do it with nothing connected. Again, I ignore it, as it is a very common thing for electronics to do this when they power up.