Why RMS?

Oh wow. My budget is very limited. I am selling sculptures and getting some help from my parents. I am just looking for what I like (within reason) and seeing what I can scrounge together. I only have a head unit now. I MAY only need 1 sub because I am trying to put it stealthy in a 300ZX (subcompact hatch with a hemi-topped racing engine). Pleus if I get an extra sub, i need an extra amp to feed it.
Uhh, why would you put a hemi in a 300zx? That's retarded. And contrary to popular belief, adding another sub only slightly increases output... it's not really that night and day.

 
Technically, there's no such thing as "RMS power"...it's RMS voltage //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 
Clipping is when the regular sine wave becomes a tangent wave (IIRC). Basically, instead of sending your sub AC (Alternating Current... to view this, turn on any song, and use the 'scope' visualization. That's what the signal wave looks like. When a signal clips, it flattens out at one point in the wave.) current, it sends it DC (Direct current) which lowers sound quality and over time damages the coil due to thermal repercussions. Clipping has nothing to do with your sub, it has to do with your amp / processor (Head unit, or otherwise noted.)
//content.invisioncic.com/y282845/emoticons/nono.gif.eca61d170185779e0921b0faa9704973.gif
Clipping is NOT DC. An audio amplifier cannot emit DC unless it's broken.

 
Technically, there's no such thing as "RMS power"...it's RMS voltage //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
I hate you for your d@mn technicalities....//content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

 
there's some serious mis-info going on in here that I'm sure the "technicians" that frequent this place would have a heyday with, but I'll point out a couple things.
First thing - a clipped wave doesn't contain DC, it's high frequency AC.

Max power isn't the thermal or mechanical limit of a speaker. It's nothing. Really. Nothing. That's why everyone says it's meaningless -- it is.

The reason it's meaningless is because there is no set defenition for the term - every company defines it differently. Some take the time to define it in their own terms, but comparison wise it is of no value because chances are the next company defines it differently if they define it at all.

RMS power IS a thermal power rating, and you don't, by any means, NEED to drive a speaker with an amp equal to its rms rating for optimal performance.

The fact of the matter is if you drive a 1000w sub with a 500w amp it's going to be REAL hard to cause damage because even fully clipped it's not likely a 500w amp can produce enough power to threaten either the mechanical or thermal limits of the sub. And if it approached that degree of clipping even the most newb ears could recognize it sounds like shit.

If you were to do the same thing with a 1000w amp the likelyhood of damage would increase drastically because an amp that size would produce well over 1000w when clipping at high volume.

And while it's become accepted that running a sub with an amp HIGHER than the sub's rms rating somehow reduces the chance of damage, the theory is bogus.


Well, technically you're right about the clipped signal. I was mistaken. It's not a high frequency signal, though. It's simply a distortion of the signal, although the bi-product of clipping is high frequency, it's not what it actually is.

As for maximum power, it is a real rating. It's the maximum power that the driver can take before damage is done to it's parts. Period. The damage is done by the soft parts becoming over-heated. The RMS rating given by manufacturers is the safe level in which you won't damage the driver. Some are a bit liberal, some are a bit conservative with the rating. But that's how it's meant to be.

As for the clipping VIA a low powered amp, it really depends on the sub. Now, a fully clipping 250 watt amp wouldn't be able to damage a 1K rated sub, but I'm sure a 500watt amp (there are certain things that determine this, such as quality of the build of both amp and sub) could damage a 1K watt driver. A clipped wave kind of forms a parallelogram, rather than a sine wave (Which is nice and tender), thus exposing the driver to mower power in a set time than the sine (unclipped signal) wave. Either way, a clipped signal will put a lot more wear on your voice coil(s) than a regular clean signal.

Either way, clipping an amp is damaging to the amp, and easily puts way more wear on your driver.

 
i think projectpechkuin (or somtin lik dat) bought 8 of them.
Yes I did

8-12"s... but he never finished the build 'cause he got a ticket, or arrested, or something dumb.
Well I had $18,000 ish in bills to pay for a lot of aggressive driving. Mostly lawyer costs. which I ended up selling a car of mine to pay off //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

I bought one just to have. ProjectPechkin bought a bunch and was supposed to do a build log for them, but I just saw yesterday he was doing another build. I guess he gave up.
My current car does not have enough funk to handle the pups

Once I buy another, the build log will be revived. I'm trying to find a good condition older jetta turbo diesel hatch. That would be a fun Pup Car.

Technically, there's no such thing as "RMS power"...it's RMS voltage //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
voltage is a term used to describe power, no?

 
As for maximum power, it is a real rating. It's the maximum power that the driver can take before damage is done to it's parts. Period. The damage is done by the soft parts becoming over-heated. The RMS rating given by manufacturers is the safe level in which you won't damage the driver. Some are a bit liberal, some are a bit conservative with the rating. But that's how it's meant to be.
I would only agree with you in that there ARE companies that have a fairly well defined meaning of MAX, but there is NOT a universal definition.

PEAK has a clear definition if you're talking about voltage of a sine wave (as in home electricity), but in terms of car audio Peak, MAX, Dynamic etc. all mean different things for different products. At the end of the day it's a meaningless random number chosen by the marketing department. It's not any more complicated than that.

As for the clipping VIA a low powered amp, it really depends on the sub. Now, a fully clipping 250 watt amp wouldn't be able to damage a 1K rated sub, but I'm sure a 500watt amp (there are certain things that determine this, such as quality of the build of both amp and sub) could damage a 1K watt driver. A clipped wave kind of forms a parallelogram, rather than a sine wave (Which is nice and tender), thus exposing the driver to mower power in a set time than the sine (unclipped signal) wave. Either way, a clipped signal will put a lot more wear on your voice coil(s) than a regular clean signal.
A clipped signal (square wave, or becoming square) at the same voltage contains more RMS POWER than an unclipped wave. A perfect square wave produces 2x the power of an unclipped sine wave of the same voltage/freq. So IF a 500w rms amp were fully clipped (close to a square wave, but not perfect) a sub that can truely dissipate 1000w should not be damaged. Plus, the sound of the sub at that point would be VERY difficult to listen to. So if someone's damaging speakers because they're listening to a fully clipped amp they shouldn't be involved in this hobby anyway.

The shape of the wave (the fact that it's going from a smooth sine wave to square) has no bearing on speaker damage, only the fact that the speaker has to dissipate more power, i.e. heat.

Clipping ejumukayshen.

http://www.audiogroupforum.com/csforum/showthread.php?t=4332&highlight=clipping

 
Technically, there's no such thing as "RMS power"...it's RMS voltage //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
in car audio what we call RMS power would be better described as "Average Continuous Power".

voltage is a term used to describe power, no?
Voltage CAN be used to CALCULATE power, but so can current and resistance. Voltage quantifies potential. I don't think you can say it "describes" power.

 
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