HELP - How Hard is to Blow a Bass Driver


As I came home I see my little brother and his friend BLASTING a Prodigy song in my listening room. I don't know the song but it was about 1 MIN. of just full loud annoying bass only (the kind you hear in Honda Civics while the liscense plate is rattling). As I ran into the room to lower the volume I saw the Driver shaking like CRAZY. Not "in and out" motion but more like shaking erratically all over the place.
Amp is the Exposure 18(70 watts rms)
Speakers are the PMC Fb1
Volume at 12 o-clock

I'm concerned that there might be damage to the Drivers. I can't hear any damage but could there be internal damage (coils)that might show up later on? Any way to test for damage?

Thanks for your help as I am stil in a cringing state
dr_balance
Hey Barry;

I would like to offer another way to really--aw shucks I really want to use the F*-word--up your speakers, and that is with one of those 'test CDs' that push the speakers to the limit. I blew out my cute little horns sitting on top of my very expensive speakers when I used one of these CDs and paid no attention to the small print warnings about turning down the volumn when running this so-called "test".

Bummer.
Dr balance,

The fact that you heard distortion with deep bass only is what
you would expect if the amps were driven into clipping.

It takes a lot of power to do the deep bass notes - so they
are the most taxing for the amplifiers.

The distortion - which is often described as a "cracking"
sound is what you expect to hear from an amp that is clipping.

If that's what you heard - then the tweeters could have
been under some stress - but if they are still working -
then you probably corrected the problem in time.

The problem is basically too much power and hence energy
going to the tweeter which heats them up. The coils can
get so hot that they melt - and that ruins the tweeter.

However, if you correct the situation quickly, which is
what sounds like you did - then the coils just got hot
but didn't melt. So they'll be fine.

If they are damaged - you'll know it - the tweeters won't
work.

But if you don't notice a problem - then your speakers are
OK - and I wouldn't worry that there's some "hidden" damage.

Go back to enjoying your stereo system.

Dr. Gregory Greenman
Physicist
Dr. Greenman, thank you so much for your post. You made me feel tons better. That is what exactly i am going to do "go back and enjoy the music" thank you for your post.

-Dave
I had my monitors clip when I used one section of a bi-wired speaker cable (I left the other pair speaker wire on the floor with the leads up in the air) and turned the volume up fairly high.

My amp was a 180 watt at 8 ohms. My monitors were 4 ohms.

Can someone please explain to me how this could happen is my amp is POWERFUL enough to handle such loads from my monitor?........