sub bottoming out

what causes a sub to bottom out? to describe, its at high volume and the sub either distorts or breaks up at certain levels. i've had this happen on a few systems and am wondering if its not enough airspace or just if its the sub itself.owner of

Motion Marine & Car Audio

the florida keys

In a ported box, the wrong port size or box volume too large.  Another reason is amp clipping.  Were these in systems you built?Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

The gain on an amp set too high (90% of the time). Too much power causing the coil to leave the magnetic gap. Straight DC mind you that will fry the voice coils. Wrong size box and or port as the good advice above mentioned.Top Secret, I can tell you but then my wife will kill me.

its a single infinity perfect 12" in a sealed .88cu box with polyfill down fire. the air space is close to specs. im thinking the gain might be to high. its only on high volume and deep bass notes.owner of

Motion Marine & Car Audio

the florida keys

Gain is too high or bass boost is too high. Turn both or either down and see what happens.Top Secret, I can tell you but then my wife will kill me.

Plus that sub is not designed for down firing installation.  That could be part of the problem... although I agree with Rob's diagnosis as the most likely.Support the12volt.com

What are some good firing down subs.Will the polk mm104 work in this application?

dyohn, how did you come across the info on the perfect not being designed for down fire? why would that affect the sub? im interestedowner of

Motion Marine & Car Audio

the florida keys

Here's a post from before with down firing info.  https://www.the12volt.com/installbay/forum_posts.asp?tid=30658&KW=down+firing.  It actually depends on which Perfect you have.  The SVC 12.1 calcuilates to about 3.5% sag, so it could theoretically be used down-firing, although it has more sag than I'd like to use.  I say max is actually around 3%.  The more sag a woofer has, the less power it can handle if mounted down (or up) firing, since gravity reduces Xmax.Support the12volt.com

For down firing subs...I would go with Audiobahn.  I see them down fired all the time at shows and in magazines.