[updated:LAST EDITED ON 08-Jan-03 AT 06:02 PM (EST)]dnewma04 your wrong. a speaker can be blown running too little of power. we already discussed this earlier and an audio technician stepped in. take a look at the bottom of this thread. https://www.ford-trucks.com/dcforum/DCForumID96/596.html
randawg you are right. you get a star

 

[updated:LAST EDITED ON 08-Jan-03 AT 06:21 PM (EST)]i dont see how a speaker can be blown by using to little power. if its a clean undistored signal then it should be fine. look at it like this. someone installs a high quality speakers in there truck with the stock radio, which pushes out lets say 5x4. the speakers are rated for 8-50rms, will he blow them? no unless he has the bass and/or treble settings high and sending a distorted signal to them. when u add more power to it, they'll get louder and more clean sounding. i used to run a 12" sub off a computer sub out put (15w) the sub was rated from 50-150rms and i ran it for at least 6 months without a problem. now i know people (not going to mention anynames) are going to get all technial with waves and terms and mumbo jumbo which i dont understand or really care to right now but they should dumb it down a little for us who dont understand it. bottom line is as long as its a clean, undistorted signal, underpowering it wont harm the sub/speaker.

PS: also when using a ported box, running a sub under the tuned Hz will blow a sub easily due to less control over the cone over a sealed. most people who dont (im saying most, not all) blow a sub do to over excursion, thats why most people use a subsonic filter to control the sub movement so it doesnt blow as easily or at all.


PPS: now im only 17 and i have been taught by some very good, knowledglable people over the past year and i know im still wet behind the ears i find myself better educated then most people.

 

1968F250LWB sure knows his silicon though, I was surprised to see he never heard of a class D amp. Anyway, not only clipping can kill a sub. I am all but positive my JL wasn't seeing a clipped signal when it died. I scoped it all from the head back. I don't let my equipment clip. There is more to this than is generally known. It seems the more I learn, the more I realise I have yet to learn. So it is with all of us I suppose. No grudges held by me, I respect a man that stands by his guns.

 

Oh no, not you too.

I thought you'd have my back on this

Go read all this carefully.

 

also id like to say, class D doesnt mean digital. at least i dont think. it means the effiecny of the amp. class a is least and class T is most. only even read about maybe 2 digital amps ever at termpro.

 

[updated:LAST EDITED ON 08-Jan-03 AT 06:41 PM (EST)]the d i class d doesnt mean digital i dont think. but most class d amps are digital. thats they way i understand it. i used to work at an audio shop as an installer during the summer. i am positive a sub can be blown from too little of power. i saw it with my own eyes. i talked on the phone to a kicker technician and he explained it to me just like that audio technician did in the thread i posted. i would think the engineers at kicker would know what they were talking about. the whole phone call was to see if they were to honor the warranty or not because we werent sure if it had been physical abuse or because of the amp power itself. sent it off and results said blown because of insufficient power.

 

The 400W amp will have better control over the sub than the 150W amp. Lets say the 400W amp is putting out 120V at 150W, and that the 150W amp is only putting out 65V at 150W. The sub will have to move more with 150W. Which will result in furhter excursion of the sub, thus maybe bottoming the sub out.

 

>i talked on the phone to a
>kicker technician and he explained it to me just like that
>audio technician did in the thread i posted. i would think
>the engineers at kicker would know what they were talking
>about. the whole phone call was to see if they were to honor
>the warranty or not because we werent sure if it had been
>physical abuse or because of the amp power itself. sent it
>off and results said blown because of insufficient power.

Yep, that's what I tried telling dude. He's up against everybody.

A class D amp can be called a digital amp I guess. But, really its a switching amp. When the transistors are on, or conducting, there is no voltage across the transistor. When the transistors on off, and there is a significant amount of voltage across them, there is virtually no current flowing across them. This makes the class D amps extremely efficient. But they sound like crap, or atleast until a few yrs ago when it became possible and economical to filter the square waves down to a decent sinewave. Maybe filter isn't the right word, but it'll have to do. Actually, the class D design is about 50 yrs old. Like I've said before, nothing is really new, we knew all we needed to about audio decades ago.

 

eco can u dumb it down a little, i dont really know the the technical jibberish yet.

 

>The 400W amp will have better control over the sub than the
>150W amp. Lets say the 400W amp is putting out 120V at 150W,
>and that the 150W amp is only putting out 65V at 150W. The
>sub will have to move more with 150W. Which will result in
>furhter excursion of the sub, thus maybe bottoming the sub
>out.


You may have hit on something there. What determines how many volts an amp will put out?

 

[updated:LAST EDITED ON 08-Jan-03 AT 07:13 PM (EST)]>eco can u dumb it down a little, i dont really know the the
>technical jibberish yet.


V=IR Ohm's law

Better yet V=I(Xc+Xl+R) where Xc is called reactance of a capacitor at a given frequency F. Xc=1/(2*PI*F*C) where C is in Farads.

Xl=2*PI*F*L where L is in Henrys. Xl is the reactance of an inductor at a given frequency.

R is of course resistence

Reactances are resistences also, only they change for every different frequency.

Got it? This is about all you really need to know, for now.

 

Randawg,

Speakers don't have a damping factor. Amplifiers do, and it is simply a ratio of the load impedance of the driver divided by the output impedance of the amp. You are correct that it will help determine how controlled the amplifier is but it has nothing to with power. The output impedance remains the same regardless of how much power is provided. On the driver itself, heat can effect the impedance of the driver, which will effect the DF when measured across the terminals of the driver. This is where the real world really destroys the merit of a high DF amp. Just run the numbers and include the series resistance of the typical speaker wire into the output impedance of the amp, and you will see that anything over 100 (high estimate) will have little to no effect.

So lets eliminate DF as an issue in 99.999% of car audio amps. Even a poor quality amp will have a DF close to 100. Even marginal quality amps will make it pretty much irrelevant.

Be back later....gotta go.

I will bring back up from Manville Smith, RC, DN, Dan Wiggins, David Hyre, Nick McKinney, Thilo and hopefully others when I return.

 

Class D is digital in name only. It was named that by switching circuitry that is switched to on and off positions similar to the 0 and 1 concept in digital. Class T is essentially a class D amped tweaked to allow it to work full range, which class D has trouble with. It has similar effeciency to a Class D amp. The Class A being the least effecient is just a coincidence.

 

>dnewma04 your wrong. a speaker can be blown running too
>little of power. we already discussed this earlier and an
>audio technician stepped in. take a look at the bottom of
>this thread.
>https://www.ford-trucks.com/dcforum/DCForumID96/596.html
>randawg you are right. you get a star

Well Damn, I guess I am wrong since rbrendel said so. I stand corrected...

seriously, that link almost backs up my point.

If you don't have anything to bring, don't bring it. Randawg and I were actually backing up what we were saying, try to do the same.

 

haha? first you say there is no way in hell a speaker can be blown when underpowered and the linked thread proves that it can. what is your argument now? im not trying to start any fights here im just showing the solution! the link i brought clearly describes why and proves it can happen. and i thought i had alot to bring, you seem like your a smart guy, dont get all bent out of shape because your wrong on something. ease up a bit! ;-)