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Discussion Starter · #1 ·
Yeah i hate this. I just got flamed on a local car site for saying that im underpowering my sub isnt going to damage it.

basically here is my original post:
Jl amps are notorious for being complicated and i am just not impressed at all with my sound system right now. (500/1 and 13w7)

the spl drops off like crazy below 60hz (where this sub is known for playing well).

the amp is a 500/1 btw.

anyone in the area bored and wanna lend me a hand?
someone went on to tell me im "severely underpowering my sub" and its going to ruin it.

i said are you serious? underpowering a sub is only dangerous when you clip the amp which will cause the vc to overheat and damage the sub. my gains are set carefully on my amp so this is not the case. also from what im reading the 500/1 is underrated in power and puts out closer to 750wrms.


NOW a professional car audio company comes in my thread:

INCORRECT SIR

Underpowering a sub can damage the woofer just as easily as over powering it. The voice coil(s) are built/designed to handle a specific power window and you need to achieve that for optimum output. You could also get a "two fer" and damage both

they have power ratings on woofers for a reason, regardless what the google machine will tell you

Now your "closer to" rating of 770 is a PEAK output, which means that amp will not be putting out that power all the time, and that power would be with the gains cranked heavily causing the amp to work harder and possible overheat or damage the internal circuits of the amp

NEVER plan on the "closer to" rating of an amp ... if that amp would blow pushing that woofer your warranty would be void.

The reason the sub wont move is you are under powering it ...

If you want to stop into the store we could take a look at it and make sure everything is wired correctly and tuned accordingly.

BUT I STRONGLY SUGGEST
either going back to the other woofers or upgrading the amp

are you kidding me?

then the guy in the first post rights

^ thank you sir. i tried to help, but i guess itl take fin up that monster with that amp before a change is made.

all that aside, i deff agree with ian, upgrade ur amp or go back to the cheapies. good luck on whatever u decide
and the car audio company responds

i deal with stuff like this all day ... sometimes people just need to experiment with stuff to learn, i just hope he doesn't cost himself some coin learning

also the box size for the w7 has some control in this

but like i said, stop by the shop if you want and we will figure it out

someone else chimes in:
he has a 13 w7,i belive there supposed to be ran with 1000wrms 2000 max.your amp is too small for the 13w7.you need a bigger amp to push that beast.ive had all jlaudio stuff for years.its some of the greatest on the market.by only runn 500 watts through the sub your seriously depriving it for power.even if its a jl amp.this is the sole reason i belive that jl made the 1000/1 amp.for this sub,ive seen 2,1000 watt jl amps hooked up to a 13w7 and not blow it.ian is exactly right about the underpowering of the sub could cause it to be worn down more quickly.i would say go to the jl website and check it out for yourself as in the power charts.the jl amp is very strong.for some reason i managed to blow 2 brand new jl 10w3v3s last year with my 500/1 jl amp.the store that i got them from was hesitant to give me my money back even tho it wasnt even a week and i made it very clear to the salesman/owner that i wanted a set of subs that could hold the power of the amp.sp i went to speed of sound and got hooked up and paid a little over a 100 bucks and i went from 10s to 12s.needless to say i hit about 143db in my old golf with a 500/1 and 2 12w3v3s.for those who dont know thats about the equivelent to a 13inchw7. i really think there are a few options here.1 keep the 500/1 sell the 13w7 and get a 12 or 15 w6 or get 2 12 w3v3s.2,sell the amp and get a bigger amp but thats gonna cost more money. if you do some smart shopping you should be able to get rid of the 13w7 and get 2 12'sw3v3s for no extra money spent.you would get about the same power but you will get better sound b/c there rms falls right inline with the amp rating.i know its alot of jibberjabber but this should make some sence.
also i may not be a mecep certified installer but i did just stay at a holiday inn!

BLAH BLAH BLAH

they keep telling me im gonna ruin my sub by underpowering it. tey all think im stupid because the car audio "professional" on the forum told me i was.

am i wrong???? can someone please give me some respectable references too to bakck my side u?

im more worried about protecting my pride right now than my system:blush:

thanks for your help
 

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As long as you are not clipping the amplifier you cannot damage a sub by "under-powering it." Because if that were the case then it would just die sitting there with no input.

Power does not dictate frequency response

Speaker drivers CAN be ruined by "underpowering them" when you are severely clipping the amplifier, one way is by raising the AVERAGE power level to the subwoofer, basically heavy compression, but you will know it if you are doing this. Another way is because when a signal is clipped you will get spectral content up above the original material, this tears tweets up, but the sib driver has an inductance such that this upper spectral content is not allowed to be transformed into heat.
 

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If your not clipping the amp, there is no problem, if you play at low volume levels, even a 2000W amp will only deliver a few watts, and I really mean a few, 5 or something like that...

If a sub isn't going low and it should, try another box (lower tuning if ported, bigger if sealed).

greetz,
Isabelle
 

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Hey, no bad-mouthing F&F. 2 more days!!
I can't wait, because even though I'm not gonna watch it. I'm still gonna rev on every vette with my civic and totally drive like an ******* under semi's and ****. I may even take my back-seat out to shave off some weight.
 

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here is one for the ages from before there was dirt :eek:

Quoted


Manville on average power over time:

The only thing that thermally damages speakers is power... more specifically: average power over time.

I'll explain...

If you take a given amplifier, let's say 100 watts and operate it just below clipping with music material, the "Crest Factor" of the amplifier's output is equivalent to the "Crest Factor" of the program material.

"Crest Factor" is the difference between the average level of the signal and its peak level. For example, a pure sine wave has a "crest factor" of 3dB, meaning that it's peak level is 3dB higher than its average level. We all know that 3dB represents a power factor of 2, so another way to look at it is that the peak power of the signal is twice that of its average level. So, if we play a sine wave on our 100 watt amplifier, just below its clipping level, the average power (over time) the speaker is needing to dissipate is 50 watts.

A true square wave, by comparison, has a crest factor of 0db, so it has equal average and peak power. Our 100 watt amplifier, playing a square wave, unclipped, into our speaker requires that the speaker dissipates 100 watts of power (twice the heat as a sine wave).

Music has a significantly higher crest factor than sine waves or square waves. A highly dynamic recording (Sheffield Lab, Chesky, etc.) typically has a crest factor of 20dB or more, meaning that its average power is 100 times lower than its peak power. So, if we play our 100 watt amplifier just below clipping with the typical audiophile recording our speaker is only needing to dissipate 1 watt of average power over time.

Modern commercial recordings typically exhibit crest factors of around 10dB, meaning that the average power is 10 times lower than the peak power. So, our 100 watt amp just below clipping would deliver an average power over time of 10 watts that the speaker has to dissipate.

Okay, so what happens when we clip the amplifier (which we all do at times). When the amplifier enters into clipping, the peak power no longer increases, but here's the KEY... THE AVERAGE POWER CONTINUES TO INCREASE. We can often tolerate a fair amount of clipping... as much as 10 dB or more above clipping with a reasonably dynamic recording... a bit less with a compressed commercial recording.

So, if we turn the volume up 10dB higher than the clipping level with our Sheffield Lab recording, we have now reduced the crest factor of the signal reaching the speakers by 10dB... so instead of needing to dissipate 1 watt average, we are asking the speaker to dissipate 10 watts average, and we're probably ok.

If we turn up the volume 6dB past clipping on a compressed commercial recording (or bass music recording), we have taken the crest factor of the signal from a starting point of 10dB to only 4dB, asking the speaker to dissipate an average power of 40 watts instead of 10 watts... that's FOUR TIMES the average power, which generates four times the heat.

SO, in most cases, the reason clipping can damage a speaker really has nothing to do with anything other than an increase in average power over time. It's really not the shape of the wave or distortion... it's simply more power over time.

When someone plays Bass Mekanik clean (unclipped) on a 1000 watt amplifier the average power is 100 watts (10dB crest factor). You can also make 100 watts average with Bass Mekanik by heavily clipping a 200 watt amplifier.

If someone is blowing a woofer with 200 watts of power due to a lack of restraint with the volume control... they will blow it even faster with a 1000 watt amplifier because they will probably turn it up even more and now they have more power to play with... this is the recipe for aroma of voice coil.

When woofers are rated for power, an unclipped signal is assumed. We use test signal with a crest factor of 6dB for power testing and can run a speaker at its rated power for hours and hours on end without thermal or mechanical failure. For example, a W1v2 can dissipate 150 watts average power for eight hours or more with signal peaks of 600 watts. So, we rate the speaker for 150W continuous power. This way, when a customer needs to choose an amp for it, they will hopefully choose one that can make about 150 W clean power... Even if they clip the bejeezus out of that amplifier, it is unlikely that the speaker will fail thermally. This is a conservative method, but it needs to account for the high cabin temperatures in a car (think Arizona in the summer) which significantly impacts heat dissipation in the speaker. A top plate that starts at 150 degrees F is not as effective at removing heat as one that starts at 72 degrees F in the lab... and this affects the ramp up of heat in the coil.

DISCLAIMER: The frequency components of clipping can affect tweeters due to their low inductance and lack of low-pass filtering. Clipping essentially raises the average power of high frequencies to a point that can damage tweeters... Woofers and midranges couldn't care less about these high frequency components because their filtering and/or inherent inductance knocks that stuff out of the picture.

Best regards,

Manville Smith
 

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Ghost, copy and paste THAT. If they ask who Manville Smith is, LAUGH AT THEM IN YOUR SUPERIOR KNOWLEDGE.
 

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HBG Tuned. Here Boneheads Gather?

They're wrong. Part of the motor in the speaker is just an electromagnet. If you don't give it enough power it's just not going to move as much away from the pole pieces.
 

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Discussion Starter · #16 ·
x10,000. Don't get audio advice on a tuner forum.

Stay here and you'll learn more than you EVER will there.
hah yeah so true. i was just looking for someone local but i gues no luck. def not taking it to that guy.

pisses me off he is a pro audio installer and still doesnt know this stuff. haha i guess all he really has to be good at is fiberglassing and installing tv screens:rolleyes:
 

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Discussion Starter · #17 ·
Well, my advice is to not ask idiots for help. That forum looks pretty friggin ghey.


purely because of this: "Fast and Furious" - HBGtuned Private Showing! - HBGtuned.com
actually its not a bad tuner site. but they obviously dont know much about CA.

and in that thread defense, the forum rented out the whole theatre so we can make fun of the movie without getting in troube:cool:


oh and we will see how this goes because the Pro audio guy also happens to be a mod on the forum...
 

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hah yeah so true. i was just looking for someone local but i gues no luck. def not taking it to that guy.
I'm SURE there's someone here that's local, positive. Lots of people here.

and renting out a movie theater for making fun of a movie FTMFW!
 

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As long as you are not clipping the amplifier you cannot damage a sub by "under-powering it." Because if that were the case then it would just die sitting there with no input.
That is a great observation. :laugh:
 

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Can someone post that in the thread where someone is arguing with me about whether or not clipping hurts speakers?

I'm REALLY tired of having that discussion.
 
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