is a bigger amp rms going to kill subs

lol - of course hifonics is going to say their amp ratings are "true."  What did you expect them to say, "uhh, you're right, they aren't true" ... ?

Hey guys, a couple points.  First of all, power ratings on subwoofers are usually thermal ratings.  However the actual mechanical power handling is determined by the enclosure used, and can be less that the thermal power handling of the sub.

Secondly, distortion does not damage subs ever, even when clipping.  It is too much power that damages speakers.  When you clip an amplifier it is the excess power produced that is the problem, not the distortion.

Steven Kephart

Adire Audio

OK Steven are you telling me that distortion and clipping never damages a speaker and never cause them to heat up more. If thats what you are trying to say than I need a big ass explanation because that goes against everything I have ever been taugh and honestly dont buy it. Make me a believer Steven, Make me see the Light :)

Nope.  I'm just saying that distortion isn't what kills the sub.  It's the excess power which is created when clipping an amplifier.  Think about it this way, would you say that too much light burnt out a light bulb, or too much heat?

I actually prove it most every day.  I am constantly distorting speakers from clipping, but never damage them because the power levels are never high enough.  In fact, here's a video of one of our subwoofers with a 1600 watt rms rating (using the pro sound standard to rate the sub) powered by an amp rated at 250 watts: http://www.woofervids.com/displayimage.php?album=7&pos=25  As you can hear, there is a lot of distortion being produced because that amp is clipping quite a bit.  But the speaker doesn't care.  I'm more worried about mechanical failure since it's running free air than burning the voice coil up.  If I dropped that sub into an enclosure (increasing the mechanical power handling of the sub) and ran that amp into full clipping, it will run all day long without a problem.  This proves that distortion doesn't kill a sub, but power does.

Steven Kephart

Adire Audio

Steven, you might be a little picky about word choice when the average guy is talking about the sounds he hears coming from a speaker that doesn't sound right.  You're more technically knowledgeable than the majority, so "distortion" to you is somewhat different than it is to the majority who use the word to describe the problem they hear when an amplifier is driven into clipping range.  While it may be clipping that destroys the speaker, it is distortion that is the tell-tale sign that something is wrong.  We can't hear clipping, can we?

With the lightbulb analogy, when  you see a light bulb burn out you will see a bright flash first before it dies, but you don't feel excessive heat at the same time.  Although it was heat that killed the light bulb, it was light that indicated the problem.  That's also descriptive of our senses when a speaker is being fed a clipped signal....we hear a difference, and that difference is distorted sound.

I don't get this part.  Doesn't a clipped signal mean that there are DC volts freezing the voice coil and stopping or limiting movement?  Which causes overheating?  Which could damage a speaker even if the power level wasn't too high?