My Focal Access 130a woofers make a hard vibrating click noise. Not necessarily at high volume but on big bass. The louder its turned up the louder the noise. It isnt distorting and one speaker does it much more than the other. I swapped them side to side and its the sepaker not the channel in question.
If anything Id say the speaker is possibly going full travel? Any ideas - better sepakers or could it be adjusted from the Amp gain or something?