is a bigger amp rms going to kill subs

No, gain is set to match the deck at higher level than you would normally listen to music at....usually at about 3/4 of the way on the deck volume control.  Keep that max cutoff in mind thereafter when you are cranking the jams.

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 :)

Ravendarat wrote:

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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 :)

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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: https://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.

Steven wrote:

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I am constantly distorting speakers from clipping, but never damage them because the power levels are never high enough.

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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?

stevdart wrote:

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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?

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I don't think I'm being too picky at all.  The reason being is that when you you say "distortion kills subs" (or the more common "too little power kills subs") someone who doesn't know any better will think it an absolute instead of a generality.  I think it is much better to educate the person rather than mislead them.  Let them know that it is power that kills a sub and that distortion is your tell tale sign that you are clipping the amplifier.  Saying that distortion kills subs is incorrect as I proved in the video above.  The speaker does not care how much distortion is being sent to it.  All it cares about is how much power is sent to it.  Heck, to a speaker distortion looks no different than an audio signal and it will reproduce it as such (unless the power level is too high).  In fact, there is some clipping (and distortion) recorded on a lot of modern music. 

stevdart wrote:

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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.

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Ah, but who says that a bulb "lighted" out?  Everyone says it "burnt" out because they understand it was heat that caused it.

stevdart wrote:

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Steven wrote:

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I am constantly distorting speakers from clipping, but never damage them because the power levels are never high enough.

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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?

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Instead of tackling this one on my own, I'm going to have my boss step in and explain this one since he's the amplifier and speaker engineer.

Steven Kephart

Adire Audio

sorry to butt in but i just want to say that everything that steven is correct, if you were to try such a thing you would see what hes talking about. distorting at low power levels wont destroy a speaker. it will sound bad, yes. distortion only destroys when you have a truck load of power behind it.

i dont know if this statement is correct , its like when u set gain on an amp; you set the gain at a low volume so you can hear distortion/clipping with out harming the speaker.  Correct?

Hi all,  a few things...

- There is NO DC present in a clipped signal/square wave.  None.  A square wave is a summation of sine waves (cf. Fourier et al); there is no DC component present.  It is a summation of a base sign wave (of the frequency of the square wave) plus decreasing amounts of odd harmonics.

- The average power of a sine wave is 1/2 the peak power (RMS voltage of a sine wave is 0.707 times the peak, power is V^2/R, so you have 1/2 as the average-to-peak ratio of power in an amp).  The average power of a square wave is equal to the peak power (RMS voltage of a square wave is equal to the peak, so they are the same).

- Power is what thermally kills drivers.  Take a 1000W rated driver, and run it with a 50W amp that has 100% THD - purely clipped into a square wave.  The driver won't care.  Now take that same driver, and feed it a 5000W amp that has 0.001% THD - the driver will cook amazingly quickly!  Even though the THD is 5 orders of magnitude lower, it is the POWER delivered that kills the speaker.

_ The reason clipped signals "kill" speakers is because of the increased power delivered.  Clip a signal, you increase the average power delivered.  Run a 1000W rated driver on a 700W amp, and clip the amp - you can generate up to 1400W of power with heavy clipping.  This burns the speaker out.  But remember, use a 100W amp and the same amount of clipping (distortion) and it's not a problem (you can generate up to 200W of power with heavy clipping).

It's the power delivered, NOT the format of that power that kills the speaker, for any AC waveform.  And all audio signals you can get - short of a total amplifier meltdown - are AC.  The only way you get DC out of an amp is if the amp is damaged and malfunctioning.  You cannot change the gain settings, EQ, bass boost, etc. to cause an amp to generate DC outputs (at least no amp that I know of - they are all AC coupled on the inputs and for good reason).

Dan Wiggins
Adire Audio

theyre we go a much better explanation