underpowering subs = damage?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=69552
Printed Date: April 25, 2024 at 7:25 AM
Topic: underpowering subs = damage?
Posted By: d43m05
Subject: underpowering subs = damage?
Date Posted: December 29, 2005 at 11:23 PM
I've just picked up a pair of CompVR CVR12, dual 2ohm subs, and i was wondering.
The rms of the drivers is 400 watts, but i've seen them listed with 50-400 as rms. Would the drivers be damaged if i run them with approximately 160 watts, or would sound quality just suffer a bit?
Replies:
Posted By: dwarren
Date Posted: December 29, 2005 at 11:33 PM
It won't hurt them a bit, but don't get over zealous with the gain in hopes to achieve more volume (clipped signal kills speakers). I can't say you lose "sq" but there be a loss of volume in comparison to 400 watts.
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Posted By: Blowntweeters
Date Posted: December 30, 2005 at 12:45 AM
i would have to agree with dwarren. also if you are running 160 per sub from a quality amp SQ should be fine.
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1974 ford pinto 4 15" punch Z power punch bd 1001 pioneer DEH-6700
Posted By: DYohn
Date Posted: December 30, 2005 at 1:23 PM
Underpower = damage = BULLSH*T. Overpower = damage = truth. ------------- Support the12volt.com
Posted By: d43m05
Date Posted: December 31, 2005 at 5:12 PM
I know this is a stupid question, but the glossary didnt help much, and neither did a search.
Could someone define more precisely what clipping is/does and how to define when it occurs?
My (moderately uneducated) guess is the driver will "belch"
Posted By: dwarren
Date Posted: December 31, 2005 at 5:29 PM
This will explain it -------------
Posted By: Steven Kephart
Date Posted: January 01, 2006 at 1:06 AM
DYohn] wrote:
nderpower = damage = BULLSH*T. Overpower = damage = truth.
It's amazing how people will argue this with me though. I even had a guy supposedly going to school for his EE degree argue this. Here's a link to anyone who wants a good laugh: https://www.g2ic.com/forums/showthread.php?t=130688&page=1&pp=20&highlight=kephart
Posted By: menace2sobriety
Date Posted: January 01, 2006 at 1:46 AM
I agree too both. But I believe under powering them with a "dirty" signal does more harm than over powering them with a "clean" signal. and visa-versa Steven Kephart "from you post in the other forum" im not dis' respecting you! but under rpm-ing a engine can result in losing main bearings. if you hear a knock when you take off in a higher gear rather in first or a gear higher than an engine can take. you will hear a rattle and that's the main bearings "talking" telling you to down shift, that's the sound of the crank beating against the bearings causing damage.
Posted By: d43m05
Date Posted: January 03, 2006 at 11:53 PM
so basically
Underpower = no death
Clipping = Death
Posted By: Steven Kephart
Date Posted: January 04, 2006 at 1:56 AM
menace2sobriety wrote:
I agree too both. But I believe under powering them with a "dirty" signal does more harm than over powering them with a "clean" signal.
How could it do more harm though? Can you explain how this dirty signal could hurt the sub? Because the only way you can damage a sub from an input signal is by applying too much power, period. When I worked at Adire Audio heading up the warranty department, I used a small 250 watt plate amp to test the subs. I would constantly clip the amplifier, sometimes having the gain all the way up and yet I never hurt the speakers. They could handle way more power than what the amplifier could produce. menace2sobriety wrote:
and visa-versa Steven Kephart "from you post in the other forum" im not dis' respecting you! but under rpm-ing a engine can result in losing main bearings. if you hear a knock when you take off in a higher gear rather in first or a gear higher than an engine can take. you will hear a rattle and that's the main bearings "talking" telling you to down shift, that's the sound of the crank beating against the bearings causing damage.
Ok, so the analogy wasn't the best. But a higher impedance is still easier load on an amplifier.
Posted By: Steven Kephart
Date Posted: January 04, 2006 at 2:37 AM
d43m05 wrote:
so basically
Underpower = no death
Clipping = Death
Not necessarily. Clipping = increased power which could cause death Too much power = death
Posted By: bagedmazda
Date Posted: January 06, 2006 at 1:24 PM
i think that underpowering my subs had alot to do with 1 of my 15's f-ing up. The rms is 600 and i had 250 going to it from a crunch powerzone amp. And the subs are dvc.
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Posted By: DYohn
Date Posted: January 06, 2006 at 1:44 PM
I can drive speakers with a 100% clipped square wave signal all day long with no problems as long as the thermal and mechanical limits of the speaker are not exceeded. I can feed a speaker 100% distortion all day long with no damage as long as the thermal and mechanical limits of the speaker are not exceeded. I can exceed the thermal and/or mechanical limits of a speaker and watch it fail in short order. These are electrical and physical truths and anything else is a myth. ------------- Support the12volt.com
Posted By: d43m05
Date Posted: January 07, 2006 at 1:01 AM
I've done a bit of reading bout this.
When you apply a signal to a driver, the signal is a smooth curve, positive and negative. If viewed with an oscilloscope, the line would look like a smooth horizontal S, centered over a neutral line (no signal).
If the same signal is "clipped" the smooth sine wave turns square. Meaning the signal being produced by the amplifier is too much for the amp to handle and it clips the peaks off the sine wave.
What it seems to me is that when the signal is clipped fromt he amplifier, the square wave will cause the speaker to extend its coil, hold, then forcibly return itself to neutral again. That slight hold in between the extend and return cycles would allow heat from the voice coil to build up and drastically shorten the lifespan of the driver.
To use another engine based example.
Normal piston (or speaker cone) motion is smooth, up and down, made so by the rotation of the crankshaft (voice coil) .
Now if the piston were to get a "clipped" signal of some sort... say the crankshaft only moving 180 deg at a time, the piston will slam to the top of the cylinder, then slam back down to the bottom limit of the crank.
The possible failures that could occur would be, the connecting rod stretches or fails and the piston strikes the cylinder head. Or the crankshaft could fail and the whole assembly will stop functioning.
Posted By: Steven Kephart
Date Posted: January 07, 2006 at 2:56 AM
DYohn] wrote:
can drive speakers with a 100% clipped square wave signal all day long with no problems as long as the thermal and mechanical limits of the speaker are not exceeded. I can feed a speaker 100% distortion all day long with no damage as long as the thermal and mechanical limits of the speaker are not exceeded. I can exceed the thermal and/or mechanical limits of a speaker and watch it fail in short order. These are electrical and physical truths and anything else is a myth.
This is a good thing too because even if you did fine-tune your system to be sure the equipment wasn't causing any distortion or clipping; you would still have to worry about the source material. Especially in many of the newer, popular musical releases out now.
Posted By: DYohn
Date Posted: January 07, 2006 at 11:22 AM
Steven: Yea, whenever people tell me "distortion kills speakers" I tell them they'd better never listen to any recordings then, especially not of electric guitar.  d43m05: While a loudspeaker is simply a linear motor, the analogy of an engine is not very apt. Engines do not like to pause in their motion. An electric motor may be paused at any point along it's travel or asked to move instantaneously from any point to any other point without danger or problems, as long as the thermal capacity of the voice coil is not exceeded. ------------- Support the12volt.com
Posted By: kirktcashalini
Date Posted: January 07, 2006 at 10:01 PM
actually think about this? does this even make sence? a underpowered speaker will play like the volume is low, if the volume is low and you are playing a 2000RMS watt sub for example, obviously since volume is low it wont get anywhere near that 2000RMS watts. it will get little mini numbers, just like if you had a weak amp to that behemoth of a sub. it will just play lower. correct?  ------------- 99 Blazer LT. Yellow Top. Big 3. Infinity Kappa Speakers All Around. Jensen CD/DVD flip out. 2 Infinity Kappa Perfect 12DVQs powered by a Alpine PDX600.1 (in one custom box, building a FG box)
Posted By: d43m05
Date Posted: January 08, 2006 at 7:58 AM
kirk, you're right about the underpowering, but if you have the gain cranked so high on the amp that the signal is badly clipped, then the driver will eventually fail.
Posted By: d43m05
Date Posted: January 08, 2006 at 8:13 AM
gah, sorry bout the double post.
DYohn, you're right, the gas engine analogy wasnt the best. I was exhausted and thinking too quick for my own good XD Hopefully this explanation will suffice?
Correct me if i'm wrong.
A signal passed from the receiver to the amplifier, then amplified out to the speaker is (Ideally) a perfect sine wave, correct.
If clipping occurs, then that means the signal gain is beyond the amplifiers limits.
Say you look at an oscilloscope and compare the view on the screen of a normal, and a clipped signal. It would appear that the sine wave of a clipped signal passes outside the viewable area of the screen. Thats essentially whats happening to the signal inside the amplifier too.
Posted By: Steven Kephart
Date Posted: January 08, 2006 at 1:01 PM
Here's a great link that explains amplifier clipping thoroughly: https://www.bcae1.com/2ltlpwr.htm
Posted By: audiocableguy
Date Posted: March 21, 2006 at 3:37 PM
JBL offers this article:
https://www.jblpro.com/pub/technote/lowpower.pdf
Posted By: Steven Kephart
Date Posted: March 21, 2006 at 3:51 PM
Thanks for the link. I'm going to add it to the above sticky as it's a great source. Nevermind, the topic was closed. Maybe one of the moderators could add it?
Posted By: audiocableguy
Date Posted: March 21, 2006 at 4:17 PM
Eastern Acooustic Works:
https://www.eaw.com/support/pdf/AmplifierPower.pdf
Posted By: audiocableguy
Date Posted: March 21, 2006 at 5:09 PM
"Manufacturers will tell you that the majority of loudspeaker failures encountered by their service department are the result of improper power matching. It might seem logical to use a smaller amplifier as a safety measure; after all, it stands to reason that there won't be enough power to damage the loudspeaker.
Yet they see many more loudspeaker failures due to under powering than any other cause. When the amplifier exceeds its maximum voltage capability, it can "clip" the peaks off the electrical signal it is supplying." courtesy of EAW and Keith Clark of Pro Sound Web.
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Matching Amps To Speakers
One of the topics I’m asked about most concerns matching power amplifiers to loudspeakers. The majority of loudspeaker failures encountered by our service department are the result of improperly powered loudspeakers.
"Some may consider using a smaller amplifier as a safety measure, reasoning that they will not have enough power to damage the loudspeaker. Yet we see many more problems due to under-powering than any other cause. When the amplifier exceeds its maximum voltage capability, it "clips" the peaks off the electrical signal. Once the amplifier starts clipping, the RMS level rises and can approach peak level, meaning that your 200-watt amplifier is approaching delivery of 800 watts of nasty, distorted power." courtesy of Paul Carelli (EAW)
Also found manufactures who will not warrenty products that have been Over or Under Powered.
under
Posted By: DYohn
Date Posted: March 21, 2006 at 5:42 PM
It's semantics. People say "under powered" when they mean the amplifier rating is less than the speaker rating. But the truth is that the only thing that can damage a loudspeaker is supplying it with more power than it can handle. The amplifier rating means nothing when the amp is clipping. Operating an amplifier that is rated at less than the speaker handling capability is 100% safe AND preferable as long as the amplifier is not clipping. It is idiots who don't know what they are doing who cause amplifiers to clip. ------------- Support the12volt.com
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