I bought an pair of the rp600m one year ago and now i start to notice a peculiar noise from one of the speakers - from the woofer - at low frequencies (an example: listening porcelain from red hot chilli peppers - the kick of the drum causes an excessive vibration on the cone).
With vinyls when the stylus touchs the groove there are the issue again, its very present when a push the turntable start/stop button. When the disc are spinning is more audible in the interval of the tracks, in this case the vibration its kind of circular, there some kind of pattern.
I changed the cables, turn the position in the room, verified the bornes from the amp, changed de channels left and right and also verified the ground and energy font, the problem continues in that speaker...
I uploaded a record file of the issue so you can listen
Voz 020_sd.m4a
Voz 021_sd.m4a