Merlin TSM makes rattling noise at low and loud

I am a newbie in this area. I have a pair of Merlin Master TSM MXM. And I have been enjoying them. Today I bumped up power of the amp (iNova) to about 80% (max is 80watt), and one of the speaker sends rattling noise when playing very low frequency. Turning down the power to about 60% and it is gone. I switch cable (Morrow SP4 and a cheap-no-name-one)/speaker left-right combo. That particular speaker makes louder rattling noise. The other also makes some but less.

So, my guess is the front rubber layer of the woofer cannot hold itself in that kind of playing setting. Is it expected? I did try on SWAN 2.1P with the same setting. I heard similar noise, but far less.

Still, I'm enjoying the music. Among 100+ songs I played there is only one has extreme high and low which revealed the problem.
I'm gonna put forth a hypothesis. The low frequency notes require much more power. You can see that if you have a power meter, where the meter can be seen to move in time w the bass. So when you turn it up that much you may be clipping the low frequency notes. Or you may be bottoming out the woofer. Just guessin'.
Merlin TSM's are not really the best for playing "low and loud". Do mean rock music at full volume perhaps, where you have very deep bass? That's not their forte.

Also, have you called "Bobby P." at Merlin? Possible next step. Or, just stop playing the one song that's causing the problem :-).
tk the speaker is designed for finesse and nuance not powerful bass and slam. otherwize there would be a 12" woofer in the tsm and the would sound would not be as realistic. keep the level down to a normal one and you will be fine. they are designed to sound real. extreme bass and hf may not be fair to the speaker's design depending on how how high you have the volume set. enjoy the music, the speakers are designed for music.
if you had the 80 watt up 80% on the volume control you were probably clipping/distorting the amplifier... and that could cause a lack of control and cause the noise. on loud bass using 10 watts for eg the peak could be 10 times higher.
bobby at merlin
Also, are you certain it's not something in the room rattling in response to the low frequency energy? I've seen that happen. Just a guess.
Folks, thanks for sharing your opinions. And thanks, Bobby.

I'm pretty happy with the purchase. Loud bass is not what I want since I'm moving into apartment.