over powering subwoofers

ok bare with me. i hope this makes sence. So is there truth to the idea that you should overpower your subwoofers? Example: yours sub is 400watts rms you should be using a 500watt rms amp or is that wrong. My local stereo shop told me this, but did nt specify how much is too much to over power? or is this complete hogwash. any help on this is greatly appreciated.Boatz and Hoez

over power is ok, under power makes you want to turn the amp up past where it needs to be. you still need to be careful either way because overpowering a sub will make it heat up faster than just using the rated power. im running double my sub's rated RMS and it is just fine for normal driving and the type of music i listen to, but if i would listen to more music with really heavy bass im sure i would have probably had to buy a new sub by now. if i burp it at a competition, it gets really hot really fast. so it really all depends whether or not it is worth it to someone to over power their sub, you have to know what you are doing and know what to look out for so you dont blow your sub. running double the rms to a sub is also pretty extreme for a normal setup, if you want to overpower your sub by 10-15% it should be ok, most decent subs will take that, now your really cheap subs i would be surprised if they even take their rated rms. under powering a sub can be just as dangerous if you are reckless with your settings. when people under power a sub they also tend to want to turn their amp up to try to get more volume out of their system. the problem with this is that it usually starts clipping the amp as you start to turn up the volume. clipping is a huge cause of amp and sub failure. so once again, if you aren't careful both under and over power can damage your equipment.

The 400 watts / 500 watts scenario  you mentioned would be considered about an even match of equipment.  It doesn't make any difference which is which.  It would be just as well-matched if the woofer was rated to handle 500 watts continuous and the amp provided 400 watts.  It's all the same when the ratings are that close.

The real mismatches occur when you try to use a fleamarket sub with a good amp. Power ratings might be real close to each other only because the cheap sub is over-rated by the manufacturer.  Pick your gear by what has been proven to work well with each other, for example, what the installer / shop has installed with great success.

And, uh, excuse us if we don't "bare" with you! 

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

The bare is propper... I do all my internetz naked...;) Thanks, ya i picked up a cheap sub for my winter truck, a lanzar max10dvc and its bottoming out at with my alpine m500. It sounds fine till i turn it up. So i have a clarion wq2510d coming to replace it. So that was overpowering with rms... What about peak power? Is it bad to over power a subs peakpower rating? again ill use my m500 amp / lanzar max10 combo for the example: Sub 800 watts peak Amp 1000 watts peak Now normally i dont pay too much attention to peak numbers, but im trying get a build plan inplace for my cars show truck. And i dont wanna waste any more money then i have to. Im really more of a sq guy... But i really like hearing bass guitars and the big upright basses distinguisably in my music. Ive got a decent clarion front stage and 4 channel. But im considering a 18" or 2 15" to really play the lows And either some 6.5" or 8" midbass woofers on a bandpass Xover.Boatz and Hoez

Oh my carshow blazer is a completely different build then the truck with the lanzarBoatz and Hoez

This example is the same scenario, again with a rated 20% difference, as the former illustration, so my answer would be the same.  But pay less attention to max or peak ratings than you would with tested continuous handling and RMS ratings.  

That cheap Lanzar might just be housed in the wrong sized or wrong alignment box, too.

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

the box is .75 cuft i emailed lanzar and got the recomended enclosure size. but its more then 20% rms, and right at 20% peak. the amp come with a little paper from alpine that says rated 2 718 rms at 2 ohms. either way when i turned the stereo up to say 85% the 10"started to smoke. But wouldn't have a subs peak higher then the amps be better for risk of thermal damage?Boatz and Hoez