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"Having too little power blows woofers"
If this were true, every time we turned our system down, we would blow the woofers. This would be very expensive and fortunately, utter nonsense. Remember that the converse is true: too much average power over time blows woofers.
 

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Originally posted by JLTD@Dec 22 2004, 11:54 AM
"Having too little power blows woofers"
Do people actually say that? That's the most retarded thing I've ever heard. It doesn't even make sense.
 

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I have to disagree

Under powering a subwoofer, especially a high-end designed for large wattage, can definately harm if not blow a speaker.

"Having too little power blows woofers"

Lets say you have a subwoofer with a 500w peak / 250w rms handling, and have an amp that is 150w X 2 peak / 70w X 2 rms. The key is RMS! This amp can blow the sub given that the amp does not have sufficient power to push the woofer at nominal levels. Even if you increase the volume to its max, you are also increasing disstortion, which is the most common killer for woofers.

You need to find an amp whose RMS is almost the same if not more than the subwoofer. Never go by peak power.

My example is very general. Any audio junkie knows that variables such as voltage output, disstiortion, and enclosure can change the outcome. I have seen a customer with a brand new JENSEN amp rated at 1,000w; the disstortion and heat rating were soo poor that amp barely made 150w RMS per channel.
 

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underpowered speakers go bad because they overheat.

the speaker's diaphragm is attached to a metal coil "voice coil" that is suspended inside of a magnet. alternating current pushes the coil in and out, transducing the electrical signal into sound waves.

since we're talking about an electrically charged magnet, we're talking about heat. the heat is dissipated by actually powering the woofer. keeping it in motion disperses the heat rather well. underpower the woofer, and your voice coil isn't moving as much. over time, the coil can get hot enough to snap.

it's perfectly healthy to overpower a subwoofer, if done right. it's actually quite safer than underpowering it. i'm sure we all know peak wattage ratings are nothing but marketing, so anywhere between 5 to 10 percent over the RMS rating should be fine.

people who blow their speakers and blame it on overpowering either gave them too much power, or just turned them up too damned loud.

always be good to your ears. you'll be glad you preserved your hearing when you get old
 

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Actually the problem is the low power amp gets turned up to the point it is constantly clipping. Yes, heat is the enemy, but it's not because the voice coil isn't moving enough, it's because the amp is clipping hard and applying what amounts to DC (sound waves are AC) to the voice coil. They won't tolerate that for long without frying unless you put a DC blocking capacitor inline with the speaker. With modern amps, it's very possible to have a straight DC output with a sufficiently large input. Most high-end home audio has very low frequency blocking built-in to prevent this.

The other contributing factor is 12v automotive electrics. If you only have 12 v to work with, you've got to run a LOT of current to make even 120 watts. 10 amps at 12 v (120W) is a LOT of current to run through a voice coil. Car audio will be a lot better when the new 48v automotive standards take effect (should be 2007?). You won't need nearly as much current for high power, and the wiring harnesses in cars will get a lot smaller and lighter with the generally reduced current requirements that come with a higher system voltage.

Saying it's perfectly healthy to overpower any speaker isn't quite accurate. It's common to use a bigger amp than the speaker's rating, but if you drive it too hard, you'll damage the cone suspension (or if you're smart, blow a fuse). These days with woofers as large as some people are putting in mobile systems, you'd be hard pressed to over-power the speakers, but it can be done.
 

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Originally posted by cad455@Dec 23 2004, 06:55 AM
well, in the live sound world, it's okay to overpower a speaker. i'm not really a car audio person at all.

maybe PA system speakers can take a little more power than usual.
Ya I know for a fact...that PA systems are underrated and you can overpower them quite a bit before you will notice any distorttion etc....
 

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There is little in common between audio reproduction equipment and professional sound reinforcement (PA) equipment. The pro gear kicks ass on anything for "home" use by a huge margin.
 

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I would have to disagree.... kinda
Too much power is like saying you have too much money. It's not power that blows speakers... it's distortion... just a few seconds of distortion can blow the best subwoofer.
 

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QUOTE (lo bux racer @ Dec 23 2004, 12:52 AM) index.php?act=findpost&pid=29287
The other contributing factor is 12v automotive electrics. If you only have 12 v to work with, you've got to run a LOT of current to make even 120 watts. 10 amps at 12 v (120W) is a LOT of current to run through a voice coil. Car audio will be a lot better when the new 48v automotive standards take effect (should be 2007?). You won't need nearly as much current for high power, and the wiring harnesses in cars will get a lot smaller and lighter with the generally reduced current requirements that come with a higher system voltage.[/b]
Yeah, I know this is from the depths of yore, but I thought I would bring it up, since after all, its now 2007 and a 48-volt automotive system is news to me.
 

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heh heh... good digging! But I have been hearing of the 48V system for a while. My dad also has some motors books with articles on it. There are some inherent issues with it though... not huge ones, but issues nonetheless. They talked about 36V for a short bit, then decided 48V would be the "standard". One thing to consider is that a 12V power source applied across your hands (one hand grounded), assuming 1500 ohms or so for the body comes out to about 8 mA, which is considered non-lethal for the most part. A 48V system is getting upward of 40mA, especially if you are sweating... a much more powerful punch. This means that more care and training will need to be happening regarding electrical system work on a car.
 

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Silly rabbit.........car-audio is not for kids. Nice try though!

Myth number 2: You can run power and signal cables together when installing a system. That high pitched whine is supposed to be there. It's a good way to gauge how how fast your going. The louder the whine the faster your going, BAM! No more having to look at the speedometer.
 

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ive always read its always safer to over power speakers than it is to underpower them, both in live and in car audio.

live and car audio do share a few simliar characteristics, but application is diffrent (i write this while working at the Sounds of the Underground concert..lol)

+48V? wow thats really cool. thats like having a car run off phantom power! haha


all the installs that ive done, its always best practice to run the audio on the opposite sides of the car, but docI is right, as long as you have good quality cables it wont be as bad. esspecially with subs, it wont matter as much since you wont be able to hear the whine from it (at least in my experience when i ran them side by side)
 
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