Low watts to high watt sub?

[RandyJ 10+ year member]

I know a lil somethin somethin. I know enough not to make this guy worry about what hes doin because the underrated amp putting out an affective square wave will produce about twice as much power. If its 40w/channel real output, the clipped output would be around 80w, still only half the amount the sub is rated for. Maybe if he had full bass boost, full gain and his EQ jacked all the way up on the sub frequencies playing with his volume at MAX he would overheat the VC, but with normal listening or even some heavy listening with a clipped wave he would do no damage to his sub if it is truely rated at 150wrms.

 

[RandyJ 10+ year member]

I also determined it by observing the fact that you can't talk proper english. If english is not your primary language then I apologize. If you are though then you need to go back to grade school to learn how to spell/write/use some grammer.

 

[PowerNaudio 10+ year member]

I also determined it by observing the fact that you can't talk proper english. If english is not your primary language then I apologize. If you are though then you need to go back to grade school to learn how to spell/write/use some grammer.

i can see the type of person you are!, that cool with me, i don't have to live with it, and that statement is also irrelevant to the topic at hand.

yes I'm Latino, English is my second language and believe me i'm trying to bring perfection to my English. but just because my English is not as good as yours, does not make the information that i have provided him wrong.

here!, just some thing i look up about clipping.

why should i care about clipping?

 

[squeak9798 5,000+ posts]

if you have a sub that can take the current from a clipped signal "off course you re not going to kill it, but you could damage the amp. if its a weak sub like the RF P1 series im sure a low frequency clipped signal will do some damage to the sub, or the amp.maybe not but why risk it?.

Why not, life is all about risks //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

But seriously; fully clipping that amp to that sub, I would worry more about the amp than the sub. Which is why I told him to still set his gain and bass boost correctly.

if you feel confotable pasing clipped signals trugh your speakers by all means do it.

If the speaker can thermally handle the power, there is no reason not to. A clipped signal will not damage a speaker if it does not exceed the thermal power handling of the speaker or cause the speaker to exceed it's mechanical limits.

but dont missinform people in to thinking that its ok and it wont damage any thing because its dependent of many factors and there is no asurance that it wont damage the speakers or that it will.

See above. There is a guaranty that it will not damage the speaker if the two above conditions are not met. If the speaker has a true power handling of 150w, an 80w signal will not damage it.

so with that said, watch your gain

I said that in my first post //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

and if you hear clipping turn it down some.

Not everybody has the ear to notice distortion (clipping) at the very initial onset, especially in the subbass region where it is hard for humans to hear distortion. So, even with the "by the ear" method it is still highly likely that they will clip the amplifier //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif FYI for ya.......

 

[PowerNaudio 10+ year member]

@squeak9798

I'm curios as to how you came up with the calculation that the alleged 40Watt amp when clipping it only puts out a maximum of 80Watts to the sub!?.

 

[JimJ 5,000+ posts]

http://www.bcae1.com/2ltlpwr.htm

Read, learn, comprehend.

Anyone that thinks underpowered amps (and distortion) inherently poses a threat to speakers, I will invite you to have a listen to my 3.2 watts at 5% THD into 50-watt rated speakers, when my amplifier is finished //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Before that, I was running 1.8 watts at around 4-5% THD into 100-watt rated monitors. Guess I was doing something wrong //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

The bottom line? Properly set up your amplifier, and this isn't a worry at all.

 

[squeak9798 5,000+ posts]

@squeak9798I'm curios as to how you came up with the calculation that the alleged 40Watt amp when clipping it only puts out a maximum of 80Watts to the sub!?.

Well, chances are good that that's the highest power the amp is capable of. Given the quality level of the amp and it's "RMS" rating, I'd say it's pretty accurate as to a "worse case" scenario. Power output (even when clipping) will be limited to the peak rail voltage of the amplifier.

 

[RandyJ 10+ year member]

http://www.bcae1.com/2ltlpwr.htm
Read, learn, comprehend.

Thank you for bringing up the site. I was going to post it if he continued to argue but I left the computer and you got to it before me.

And to PowerNaudio, if you will read, I mentioned that if english is not your native language then I apologize and mean nothing by the comment I said. So you do need some work on comprehending what people say. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[RandyJ 10+ year member]

And also, that website you instructed me to is kind of mis-leading. It makes it seem as if the driver no longer moves, it just stays stationary with a signal flowing through it providing no type of movement at all and in turn, providing no cooling. The website is also focusing on high-range drivers such as tweeters.

 

[PowerNaudio 10+ year member]

And also, that website you instructed me to is kind of mis-leading. It makes it seem as if the driver no longer moves, it just stays stationary with a signal flowing through it providing no type of movement at all and in turn, providing no cooling. The website is also focusing on high-range drivers such as tweeters.

that's what DC does, depending on the signal, voltage and the amount of current available to the amplifier, limited by the switching power supply of the amp it self, a clipped signal will push that sub to a voltage level, like 35volts, holds it and pull it down to the negative side of the wave hold it and again. now! how long its stays up like that is dependent of the frequency that's being played. a good way to actually see it in action is applying a 2hz sine wave to the amp, crank the gain up and then the volume, if the voltage from your HU is higher then what the amp is capable of using, youll be able to see this effect in slow motion. and maybe even kill your sub or amp. the reason it can damage the sub, at lest say 40hz is because, the voice coils in the sub are not designed to make motion off of a dc signal so it turns the unusable power in to heat. a good sub with a heavy gauge voice coil may not suffer from it. but on a low quality sub, the amp will push that voice pass it thermal capabilities and seize it.

i know about http://www.bcae1.com/2ltlpwr.htm and understand what he stating.

im not saying that a low power amp kill subs, im saying clipping, even a low power amp can over heat a voice coil and kill that sub or self destroy.

im done believe what you want.

 

[squeak9798 5,000+ posts]

and maybe even kill your sub or amp. the reason it can damage the sub, at lest say 40hz is because, the voice coils in the sub are not designed to make motion off of a dc signal so it turns the unusable power in to heat. a good sub with a heavy gauge voice coil may not suffer from it. but on a low quality sub, the amp will push that voice pass it thermal capabilities and seize it.

1) The sub is still moving back and forth 40 times per second. There is still a substantial amount of cooling going on.

2) Most subwoofers are less than 1% efficient. So, if you are sending a pure sine wave of 200w to a sub, 198w is being dissipated as heat and 2w is being turned into acoustic output. Now, lets assume that the signal is a clipped signal with 200w of power....at the very ends (and only the very "ends") of each signal the full wattage is being dissipated. That creates a total of 2w, yes, a measely 2w, of additional heat.

 

[PowerNaudio 10+ year member]

squeak9798: on here http://www.bcae1.com/2ltlpwr.htm he explains pretty much what i have been trying to explain to you about clipping. if it applies to this particular case its all a matter of testing, like measuring the voltage at the sub, excursion parameter, how much heat can that sub despite, how much current is the sub actually drawing from that amp, since its not an actual sine wave the sub is not going to be able to dissipate the heat like it normally would, because it will lack the normal excursion required to expelled the hot air and pull in cooler air to flow through the motor and voice coil, so that heat will build up, till the thermal limits of the voice coil and glue are reached and failure of the sub occurs.

 

[squeak9798 5,000+ posts]

It's as simple as this:

Two ways to kill a loudspeaker: Exceed it's thermal limits, or exceed it's mechanical limits. Clipped, square, sine....it doesn't matter. If those two conditions are not met, the speaker will survive.

A true 150w sub should have no problem dissipating 80w worth of heat, considering receiving it's full power rating of 150w, it (at best) would be dissipating 148.5w of heat.

 

[supa_c 5,000+ posts]

Clipping a speaker just sounds nasty. Good reason not to clip stuff

My HT amp clips like no ones business, not even 1/2 volume and its clipping ( not loud)

P.S

As usual you " experts" go of on a rabbit trail and just go way way to in depth about things.

All the kid wanted was a simple answer...jeez !//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

 

[squeak9798 5,000+ posts]

BTW, here is an interesting test for you to look through (take note that there is a typo in the results section; the first "result" should say normalized voltage, not normalized power):

http://forums.caraudio.com/vb/showthread.php?t=104007&page=2

http://forum.soundillusions.net/attachment.php?attachmentid=1734

Notice what they say about a square wave and sine wave of the same power level; they could not conclude that there was any significant difference in the time to failure between a square wave and sine wave of equivalent wattage.