Memphis PR sub gets hot

sounds like your sending a clipped (distorted) signal to your sub, my suggestion is to get a larger amp that matches your subs's power ratings so you can send a clean signal to your sub.

Um, no not necessarily there Stang. Heat is a natural byproduct of producing power. Turn on a light bulb, you also get heat. Turn on your amp, you get heat. Turn on a engine, you get heat. Turn on a sub, you get heat. Heat is the killer of subs. If your sub cannot dissipate the heat generated by sustained use or by overpowering the the driver, the sub is going to fail. A properly designed sub is going to do it's best to pull heat out of the center of the speaker by means of vented pole pieces, perimeter venting, liquid cooling etc. Heat is there to stay for now. As long as you do not break the thermal barrier of the sub, heat will not be an issue.

As far as the amp goes, it may be shutting off due to it's thermal barrier being breached. This may be due to an incorrect gain setting or the amp is driving the wrong impedence for it's original design. An amp has multiple protection circuits, low voltage, low current, low impedence, excessive heat and other safety gates as well depending on the manufacturer. My bet with yours is the gain set too high and / or the wrong impedence.

i see your point of view, maybe i just mis took his info, i know a sub will get warm, mine always has,  but not hot.   i just assume'd that since he's had it running for a long time that the impedance and gain levels would have been done properly otherwise these problems would have shown up shortly after the install. 

just on a side note, here's what ya can do forbidden, move your shop across canada to the furthest point east of you, set up shop here, hire me and share your knowledge   lol

I have seen subs that were so hot that the magnets melted right off of the baskets. 11 hours of sustained top volume playtime and they finally failed.

That is about normal as well I hate to say....

forbidden is right...  Since decks produce power they naturally produce heat as a byproduct.  A lot of decks can get really hot, but still work fine.

Speaking of the headunit heating up, a few years I ago I had an old Sony CD Player (those old Sony's use to heat up ALOT) - I discovered that by removing or disabling power to the built-in amplifier output IC's GREATLY reduced the heating problem (This only works if you're using external amplifiers driven by the line outs). Not saying you should do or try this because most head units nowdays do not really heat up that much as those did.

Did it for some friends too back then and everyone was happy.