I Think I Need a Truck Already!!!

[06salterego 10+ year member]

refer to page 3

 

[IamDeMan 5,000+ posts]

OMG it is CLEARLY obvious you have absolutely no IDEA what you are talking about..

HOLY LOLLERDOUCHES BATMAN!

 

[IamDeMan 5,000+ posts]

that makes no sense... what the hell is more average power,

AND HIS SIDEKICK BRAINLESS WONDER TOO!

 

[IamDeMan 5,000+ posts]

if i am missing your point and you are unable to express it your presence on an informational subject is really a waste of energy.

Perhaps it his correct use of the english language that prohibits you from understanding. I'd say most people understand him like crystal. Unlike the drivel you are pecking out.

 

[IamDeMan 5,000+ posts]

A1 Engine Repair 05/10/2007 Pass A4 Suspension and Steering 11/09/2006 Pass

A5 Brakes 11/09/2006 Pass

A6 Electrical/Electronic Systems 05/08/2007 Pass

A7 Heating and Air Conditioning 11/14/2006 Pass

THER ARE MY CERTS TOOLS WHERE ARE YOURS...

LMMFAO!

Oh my god thanks for this laugh.

 

[bigbangtheory 5,000+ posts]

K, everyone from Hawaii, especially 06salterego can go **** Dog the bounty hunter's nutz!

Honestly Salt, you are giving Hawaii a horrible rep.

And really does your vag really get that much sand it it?

 

[SocMunky 10+ year member]

wow your that good of an edgineer you can see me thru a computer....WOW

FFS man, its ENGINEER!

 

[SocMunky 10+ year member]

whatever audioholic you can keep your theory's...ther are always several conflicting theories in life and you fail to notice how that applies here, as you can see from their write ups the to admit that many people who are respcted in the industry disagree with what they are saying. if it was so cut and simple it would be a law and not a theory, i aplaud you for sticking to what you say and i comepletely disagree with it althoug i do see how it could be misinterprited. learn and move on, you cannot even suggest that those 2 people are the absolute bottom line in any scenerio. Oh wait you are, im allowed to disagree and i have seen it with my own eyes, how things work with multiple scan tools data logs o-scopes, and other machines. So whatever you have to say will just be disregarded.

I thought the OP in the thread was the one who was supposed to be the *******? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[sqhertz 5,000+ posts]

FFS man, its ENGINEER!

for ****s sake? //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[SocMunky 10+ year member]

for ****s sake? //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

Indeed. I was too lazy to type it. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[DBfan187 5,000+ posts]

There's no DC component in a zero-centered square wave. A DC component is present when a wave isn't centered around zero anymore, not when parts of it are flat. Those flat parts indicate presence of high-frequency content, not DC.

Well, if it's changing polarity within your frame of reference then it's not DC anymore. Your square/sawtooth/triangle/sine wave, unless at a tremendously low frequency, will most certainly be changing within any size of reference frame you choose. I'll sum it up this way: if a capacitor will pass it, then it's not DC. A capacitor that will pass the fundamental will also pass a square wave unmolested (assuming the capacitor is non-polarized and has negligible ESL).

It doesn't look like DC on a scope, it's flat. DC on a scope is offset from 0, not just flat. And it doesn't work like DC in a coil--put a square wave through a coil with a high enough inductance and you end up with a sine wave. Durr...

Maybe I can add some clarification.

There's several interesting aspects of power. The most fundamental one is "instantaneous power". Power is itself a function of time, defined simply as :

Instantaneous power:

p(t) = v(t)*i(t)

For many applications of interest, including resistive heating, the useful "metric" is average power :

Average power :

Pav = Time integral (average) of p(t)

Average power is of interest anytime the waveform is changing much faster than the thermal time constants of the system ... in other words, the typical resistor has thermal mass & capacity that realize a thermal "low-pass" filter ... meaning the resistor itself is performing the "averaging" that makes average power the relevant metric for resistive heating. Obviously, the average power would be less meaningful for a power waveform that has a period of one hour, for example. Make sense?

Now, to aid in average power calculations, the concepts of "RMS" values of voltages and currents were developed. In the most general form, for power delivery into reactive loads, the Average Power is :

Average Power into reactive load

Pav = Vrms*Irms*(Power Factor)

where the power factor is simply the cosine of the phase angle between voltage and current.

From this relationship, it's easy to see, for example, that although instantaneous power can be delivered to a purely inductive load, the average power delivered to a purely inductive load is zero. This is equivalent to saying that the average power dissipated, as heat, by an inductor is zero.

A few other random comments :

- the voicecoil inductance of a sub will rarely influence the power delivery. Yes, if we consider the inductance to be in series with the coil resistance (an accurate model), it seems as though we are dealing with a reactive load, and therefore a power factor of less than unity. However, most subs are crossed-over well below the coil resistance/inductance corner frequency, so the coil inductance has little significance for power delivery.

- within the use-able subwoofer frequency band, however, there certainly is a reactive impedance near the driver's resonant frequency. And this reactive component certainly does make average power delivery calculations more complex than a simple resistive load. But an amplifier clipping will not change this reactive impedance component. The sub reaching an excursion limit will impact this "motional impedance" ... but the sub simply has no knowledge that the amp is clipping versus faithfully reproducing an input signal that appears "clipped".

- when is a signal DC? It's DC if it remains constant longer than any time constants of the system ... electrical, thermal or mechanical. A squarewave at 20Hz won't qualify ... there's at least one electrical high-pass filter with a lower corner frequency than the 20Hz fundamental, and the thermal time constants of the sub's motor & coil are most likely longer than 50msec as well.

Just lots of thoughts ... not sure any of it really helps //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

There's all the proof that is needed to prove there's no DC in clipping.

 

[02parkave 5,000+ posts]

when you learn to speak English, get back to me. untill then, your just not on my level.

until, you're. engineer your way our of that fail.

 

[duece212 5,000+ posts]

this is gonna ****...I have a feeling

that dood was right

 

[audioholic 5,000+ posts]

alright so I see what everyone is saying about there's no such thing as overpowering and underpowering as those terms are misleading. We use those terms for lack of a better term. Because we can run 1 watt with a clean signal to a 2000watt RMS sub all day and it will not heat up... ok we get it. The main idea here is sending a clipped signal through a sub will heat the voice coils up faster. We get that clipping is essentially harmonics playing simultaneously... but when you put those harmonics side by side on a graph... they create what looks like a plateau on the top of the graph which an oscilliscope sees as a square wave. Essentially when you apply this signal to a sub, that square wave or "more average power over time" generates more heat this is what most of us call Underpowering. What I call overpowering is feeding a sub ungodly amounts of power where the mechanical limits is reached and builds up heat enough to kill a sub. I believe someone got it right on the money. Power doesn’t kill subs. Heat does. Two types of signals play a factor. Some of you argued that playing a clipped INPUT signal is harmless… this is true. But play a clipped OUTPUT signal to your subs voice coil and it is potentially dangerous. o6salterego is saying that dc voltage is a flat line where amplitude remains constant. which is true. A tones harmonics will create this illusion of a flat plateau. But everyone is saying that a signal cannot be DC in that it still has a peaks a valleys like a sine wave. Essentially clipped signals is just PEAKING LONGER. In this plateau is where heat is generated. So we can safely say that ACDC is what kills subs.

I have nothing against Hawaiians, but why do you all keep coming here to tell us what DC is, yet obviously refuse to even read the quotes we give you from experts who say otherwise? Maybe DC is something totally different in Hawaii. *shrug*
Nobody is suggesting all Hawaiians are stupid (unless they are making a joke)... but you have to admit its pretty funny seeing so many Hawaiians in this thread sticking up for each other, and all coming to the same flawed conclusions.

Aloha.

 

[audioholic 5,000+ posts]

that dood was right

I knew you would be back to say that. Yet somehow, I still laughed.