# Sticky  Secrets of Amplifier and Speaker Power Requirements Revealed



## Oliver

> Secrets of Amplifier and Speaker Power Requirements Revealed
> 
> As audio/video hobbyists, most of us grew up thinking that if we have an amplifier with 50 watts of rated output power into 8-ohm speakers, and that combination produces reasonably clean and loud music, then by doubling the amplifier power to 100 watts per channel, the system would then play twice as loud. Many readers likely still believe that. Not so.
> 
> Although it's not the easiest thing to comprehend, doubling the amplifier power does not double the loudness. In the above example, the sound from the speakers would not be "twice as loud"; it would only be "a little louder," an increase of 3 decibels. How loud is that? Hearing tests with large groups of people have revealed that a one-decibel (1 dB) change in loudness is approximately the smallest audible step that the average listener can detect, so an increase of 3 dB most listeners term "slightly louder."
> 
> So why doesn't that 100-watt amplifier always sound twice as loud? Because the acoustic decibel--the decibel (dB) being the unit of measurement used worldwide to quantify the acoustic loudness of sound--has a peculiar relationship to amplifier power output measured in electrical watts. That relationship is called "logarithmic." If that word gives you an instant headache (nightmares of high-school math), then here's a simpler explanation:
> 
> If a sound gets louder by 3 decibels or "slightly louder," it takes twice as much electrical power from your receiver or amp to produce that modest increase. Therefore, a 100-watt amplifier will produce sound only slightly louder than a 50-watt amplifier.
> Incidentally, if you'd like a kind of immortality, be terribly clever and work out a system of measurement. It may be named after you. The "decibel," one tenth of a bel and named for BellAlexander Graham Bell, recognizes his contributions to the understanding of sound. Likewise, we have to thank James Watt, Georg Simon Ohm, and Heinrich Hertz for their contributions to the industry. And then there's the Lofft, a measurement of neighbors' tolerance to testing new speaker systems . . .
> 
> So far, so good. But what if it's party time, and you're listening to music "very loud," a level defined as about 90 dB Sound Pressure Level (SPL), and your speakers are gobbling up swings of 15 to 20 watts per channel on those musical peaks.
> 
> Drink in hand, you advance to the volume control on your receiver thinking, "I'll just crank this up to make the music twice as loud," and you turn up the volume control until there's a 10 dB increase in the sound level. Now your party-time goal of "twice as loud" will make huge electrical demands on your nice little multi-channel receiver or power amp. The receiver must deliver ten times as much power to double the subjective loudness. Between 6 dB and 10 dB is double the volume level, where 6 dB is four times the power and 10 dB is 10 times the power. In the aforementioned example, the amp must produce 150 to 200 watts per channel for those peaks in loudness. Therefore, every 10-dB increase in acoustic loudness--from 80 dB to 90 dB, or 90 dB to 100 dB--requires ten times as much electrical power in watts.
> 
> That's all very well if you have a monster amplifier or multi-channel A/V receiver with huge reserves of power output (most of us don't). If not, watch out. Your receiver or amp may "clip" or distort (or both), which will put a clamp on the output of the amp. When you push your amplifier into overload or "clipping," several things may happen. First, the top and bottom of the waveforms (representing the audio signals) are clipped off, generating distortion. Next, the amplifier's protection circuits are activated, removing those portions of the signal that are causing the overload, generating distortion. And finally, the amplifier's power supply may fluctuate according to the demands of the music signals.
> 
> Not everyone is affected by this scenario, of course. Some people (increasingly few, it seems) don't listen to loud music. They like background levels, and with average speakers, background levels demand 1 watt or less of amplifier power. Or they may have very efficient speakers (Klipsch, Cerwin-Vega, Tannoy, and the like) that will play extremely loud using modest amplifiers, the trade-off being a very large degradation in tonal accuracy, a definite harshness, and a complete loss of off-axis performance that accompanies horn-loaded designs. But in many situations, speakers will be damaged and distorted sound will offend many ears.
> 
> No discussion of decibels, acoustic loudness, and electrical watts is complete without an explanation of loudspeaker "sensitivity." (Another way to define a speaker's sensitivity is to look at how efficiently the speaker converts electrical power, in watts, to acoustic sound output in decibels.) Let it be said in a general way that speakers are not very efficient or sensitive devices. They need a lot of electrical power input to produce relatively little acoustic output. Nevertheless, speakers do vary quite a bit in sensitivity.
> 
> To determine a speaker's sensitivity, we feed the speaker with 1 watt of amplifier power, using a test signal of pink noise, and measure in decibels how loud the sound is at a distance of 1 meter (about 3 feet). A lot of domestic hi-fi speakers measure in at about 89 or 90 dB SPL at 1 meter. Larger speakers, with bigger woofers and more drivers, typically produce greater acoustic output; smaller bookshelf models have to work harder, and their output is typically less, often between 86 and 88 dB SPL at 1 meter.
> 
> Placing the speaker in a room helps (the walls, ceiling, and floor reflect and reinforce the speaker's sound), adding about 4 dB to its output. For example, a speaker like Axiom's M80ti has a measured sensitivity in an anechoic chamber of 91 dB SPL at 1 watt at 1 meter. But putting the M80ti in a room raises its sensitivity rating to 95 dB SPL at 1 watt, 1 meter. A 95-dB sound level happens to be "very loud," as most of us would subjectively describe it. And it is--from 3 feet (1 meter) in front of the speaker. But let's move our listening seat back twice as far, to 6 feet. Guess what happens? We instinctively know that sound gets weaker as the distance from the source is increased, but by how much? A formula called the "inverse square law" tells us that when the distance from the source is doubled, the sound pressure weakens by 6 dB. Among sound engineers, there's a common saying: "6 dB per distance double." So at a 6-ft. distance, the M80ti is now producing 89 dB. Now let's double that distance again to 12 feet, a fairly common listening distance. The speaker now produces 83 dB, which isn't all that loud at all. And if you sat 24 feet away, a not uncommon distance in big rooms, the speaker would produce 77 dB SPL.
> 
> But what about stereo, I hear you shout. Here's another oddity of loudness and the decibel. When one speaker is producing a level of 90 dB, adding a second speaker playing at the same level only increases the overall loudness by 3 dB! (The loudness does not double!). So the two speakers in stereo produce a loudness level of 93 dB.
> 
> So adding a second M80ti will raise the loudness at 12 feet from 83 dB to 86 dB. And don't forget we're still using 1 watt of amplifier power output into Axiom's most sensitive speaker. But how loud are real-life instruments, orchestras and rock bands? Now, while 86 dB SPL is "fairly loud," it's not nearly as loud as what you might hear from a good seat at an actual rock concert or from an orchestra or pianist in a concert hall. A solo grand piano can reach peak levels of 109 dB SPL, a full orchestra and chorus in a concert hall will measure 106 dB, and a rock group, 120 dB SPL. Now let's try and get our peak speaker sound levels to 96 dB, "twice as loud" as our 86-dB listening level. That isn't that difficult because right now we're only using 1 watt per channel to drive the M80ti's to 86 dB. So we'll need ten times as much power, or 10 watts, to reach 96 dB. Big deal. We've got lots more.
> 
> But things begin to change, and rather dramatically. Let's push the M80ti's to what we might experience from a solo grand piano, 109 dB. We're at 96 dB with 10 watts per channel. Let's go to 106 dB. So that requires 10 x 10, or 100 watts. Close, but not quite there yet. Just 3 dB more. Remember, we have to double the power for a 3-dB increase in sound level. So 100 watts becomes 200 watts. Yikes! Our receiver has only 110 watts maximum output! We've run out of amplifier power! And what about the rock concert? Let's lower our expectations and aim for 119 dB. Going from 109 dB SPL, which needs 200 watts per channel, to 119 dB SPL (get out your ear plugs) is another 10-dB jump and--you do the math--that requires 10 x 200, or 2,000 watts per channel!
> 
> From all this you can see the huge power requirements inherent in reproducing real-life acoustic sound levels in average or big rooms. The M80ti's are tested to levels of 1,200 watts of input power so they come very close. But the truth is that if we are seeking real-life acoustic sound levels in our listening rooms, there's a very persuasive argument for very large, powerful amplifiers. And if your speakers are less sensitive (and many are), then the power demands rise even more dramatically. Sizeable rooms and greater listening distances will also increase power demands tremendously.
> 
> And what many of us don't realize until we hear it, is that clean undistorted loud sound often does not sound that "loud." The key here is that in most or our home listening, there are small amounts of distortion caused by a lack of dynamic headroom (but more on that next month). It's the distortion that makes it sound "loud" in a domestic setting. To remove those distortions and increase dynamic headroom relates to even more power. We've become accustomed to accepting some distortion with our reproduced music, because all amplifier's distortion ratings gradually increase as they approach their output limits or slightly clip the audio signals. When that happens, we turn down the volume, because distortion starts to intrude on our listening pleasure, and it sounds "too loud."
> 
> The lesson in all this is that you can never have too much power, and that big amplifiers rarely damage speakers. Little amplifiers driven into clipping burn out speakers. In the scheme of high fidelity, that last barrier to realism is having enough power and being able to approximate real-life loudness levels. The lesson in all this is that *you can never have too much power*, and that big amplifiers rarely damage speakers. *Little amplifiers driven into clipping burn out speakers*. In the scheme of high fidelity, that last barrier to realism is having enough power and being able to approximate real-life loudness levels.


*Read and learn *^^^^ *from Alan Lofft*


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## I800C0LLECT

*Re: Secrets of Amplifier and Speaker Power*

http://www.axiomaudio.com/power.html


That's awkward. What's wrong with our links? Copy and paste I guess?


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## Niebur3

*Re: Secrets of Amplifier and Speaker Power*

Great reading!!! Thanks for posting!


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## OSN

*Re: Secrets of Amplifier and Speaker Power*

Also, having 2 speakers on each channel playing correlated music increases output by 6 dB. Also can't have too many speakers.


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## Oliver

*Re: Secrets of Amplifier and Speaker Power*

Likewise, we have to thank *James Watt*, *Georg Simon Ohm*, and *Heinrich Hertz* for their contributions to the industry.


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## Oliver

*Re: Secrets of Amplifier and Speaker Power*

^^^^^^


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## adrenalinejunkie

*Re: Secrets of Amplifier and Speaker Power*

Back up from the dead. Great read.


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## thomasluke

*Re: Secrets of Amplifier and Speaker Power*

That just screams sticky.


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## Bluenote

*Re: Secrets of Amplifier and Speaker Power*

This was great for an SQ noob like myself...I wanted to ask one question. Is there a method to adjusting gains on an amp to determine wattage going to a given speaker?


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## adrenalinejunkie

*Re: Secrets of Amplifier and Speaker Power*



thomasluke said:


> That just screams sticky.



I agree.


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## schmiddr2

*Re: Secrets of Amplifier and Speaker Power*

That was not just brilliant for the technical insight, but brilliant because of how he was able to explain and relate the information.

Stuck!


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## Riff Raff

*Re: Secrets of Amplifier and Speaker Power*



schmiddr2 said:


> That was not just brilliant for the technical insight, but brilliant because of how he was able to explain and relate the information.
> 
> Stuck!


Bravo ! ! ! ! Great Decision by our trusty MOD.


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## Thunderplains

Excellent info.. So now that I know my listening needs.. I need to get 5 of these amps..


















4 altenators, rip out the backseat and fill with batteries and I will achieve my listening levels desired.. :coolgleamA:


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## subwoofery

Thunderplains said:


> Excellent info.. So now that I know my listening needs.. I need to get 5 of these amps..
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> 4 altenators, rip out the backseat and fill with batteries and I will achieve my listening levels desired.. :coolgleamA:


Just use 16 ohm drivers and you'd only need to add 1 more battery  

Kelvin


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## Dillyyo

Good read on an easy explanation of physics 101, but I disagree with the following statement:

_ "Little amplifiers driven into clipping burn out speakers."_

Can anyone point to some verifiable empirical evidence of this happening? I've constantly driven my speakers with a clipped signal ever since I took up the hobby 24+ years ago and have NEVER had a speaker burned out. with many hours in the car and constantly pushing the system. I've had mechanical issues due to exceeding physical capabilities or application of unnatural forces to the speakers, but never one to just "burn out". 

Is the statement just to ambiguous? Maybe clarify possibly with extreme clipping, though I personally don't see the physics behind the failure mode. If someone more knowledgeable would care to clarify, that would be great.


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## subwoofery

Burned out speakers = too much power that produces enough heat to damage your driver
Burned out speakers = clipping so that it produces enough heat to damage your driver 

Lite clipping won't damage anything if your driver can withstand the heat. 

Kelvin


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## Cparker1989

Nice post.


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## Randyman...

Yep - Power is power - the speaker doesn't care if it sees 100 Watts RMS of a pretty sine wave or 100 Watts RMS of ugly clipped waveforms or even 100 WRMS of DC - thermally speaking they are the same (assuming you measure each correctly). I also blindly fell for the "under-powered amps and DC Clipping will blow speakers" mime, but learned that voice coils don't care what the waveform looks or sounds like - they care about the total work done (RMS Power, or heat)...

Of course, this is slightly skewed when talking about blowing tweeters via hard clipping - as clipping your waveform naturally INCREASES energy in the upper band - causing the Tweet that generally sees a comparatively light load to suddenly end up with a ****-ton of energy in that range thanks to all of the flat-lined waveforms and additional harmonic distortion. Took me a while to get that through my skull, too (it's not the clipped waveforms or DC themselves that kill the tweet - it's the abundance of additional energy in the tweet's pass-band that presents the tweeter with tons more RMS power/heat than it would see in an un-clipped system).

Amazing what we believe just because it is repeated enough. That's how the mainstream media works after all


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## CDT FAN

If you send your sub back for warranty because it burned out, the manufacurer can tell from the burn pattern on the voicecoil whether it had too much power or clipping.

Speaker Failure Analysis

1. Black discolouration in the middle or all over the voice coil
This is the most common damage seen and indicates that a well centred coil was driven with too much audio power for too long. The resistance of the burnt coil is often half or less the nominal value due to internal shorting. 

2. Black discolouration at one end of the voice coil.
This is also a common sight and indicates either the voice coil was not centred during manufacture OR that the damage was caused by DC current rather than audio frequency current. A large DC current will displace the voice coil to one or other extreme. A faulty amplifier is automatically suspected.


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## Dillyyo

subwoofery said:


> Burned out speakers = too much power that produces enough heat to damage your driver
> Burned out speakers = clipping so that it produces enough heat to damage your driver
> 
> Lite clipping won't damage anything if your driver can withstand the heat.
> 
> Kelvin


As I stated before, direct me to the empirical data. Been around this hobby for over 2 decades and have never seen photos or examples of this thermal degradation. This is something that would have been clearly replicated by the infinite amount of hobbyists who are always looking to push the envelope or push their equipment to the max. 

What the poster above states is the factual truth and what should be conveyed when someone brings up this discussion.


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## Dillyyo

CDT FAN said:


> If you send your sub back for warranty because it burned out, the manufacurer can tell from the burn pattern on the voicecoil whether it had too much power or clipping.
> 
> Speaker Failure Analysis
> 
> 1. Black discolouration in the middle or all over the voice coil
> This is the most common damage seen and indicates that a well centred coil was driven with too much audio power for too long. The resistance of the burnt coil is often half or less the nominal value due to internal shorting.
> 
> 2. Black discolouration at one end of the voice coil.
> This is also a common sight and indicates either the voice coil was not centred during manufacture OR that the damage was caused by DC current rather than audio frequency current. A large DC current will displace the voice coil to one or other extreme. A faulty amplifier is automatically suspected.


I'm going to call "[email protected]" on the clipping analysis. Power, Yes, but clipping?! I guess they have to make money too, right? SMH


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## Randyman...

subwoofery said:


> Burned out speakers = too much power that produces enough heat to damage your driver
> Burned out speakers = clipping so that it produces enough heat to damage your driver
> 
> Lite clipping won't damage anything if your driver can withstand the heat.
> 
> Kelvin





Dillyyo said:


> As I stated before, direct me to the empirical data. Been around this hobby for over 2 decades and have never seen photos or examples of this thermal degradation. This is something that would have been clearly replicated by the infinite amount of hobbyists who are always looking to push the envelope or push their equipment to the max.
> 
> What the poster above states is the factual truth and what should be conveyed when someone brings up this discussion.


I think you are both in agreement. I'm taking subwoofery's statement as you can smoke a coil one of two ways:

1) Too much clean power with an oversized amplifier rated well beyond your speaker's continuous RMS rating

2) With too much clipped power from an amp that is _matched _to your speaker's continuous RMS rating.


_Of course, the validity of the amp's and speaker's rated specs come into play_, but if you have a perfectly matched amp RMS power and speaker RMS power (continuous RMS specs on both counts), you can still smoke the coil with heavy-duty clipping as the amp is putting out a good deal more RMS power than it's rated for (equals more heat at the coil). All those flat clipped waveforms slamming into the +/- rails directly translate to a higher duty-cycle of the waveform - and that means more RMS power...



Dillyyo said:


> I'm going to call "[email protected]" on the clipping analysis. Power, Yes, but clipping?! I guess they have to make money too, right? SMH


Agreed 100% with that. All that article really tells you is that certain motor designs will exhibit characteristic burn patterns based off how much of the coil is in the gap, or how the coil might look if the speaker contained a manufacturing defect. There's just no way for the manufacturer (or anyone that is not intimately familiar with the system as a whole) to accurately determine "clean overpowered failure" vs "clipped overpowered failure". 

Regardless - Both scenarios will exceed the coil's/motor's RMS heat sinking abilities in a similar fashion - and both would qualify as "Overpowering the Speaker" IMNSHO.


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## subwoofery

Randyman... said:


> I think you are both in agreement.


Yup... Thanks 

It's my 7 decades in the hobby that made me learn about heating a voice coil 

Kelvin


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## Randyman...

subwoofery said:


> Yup... Thanks


6 of one; half a dozen of another 



subwoofery said:


> It's my *7 decades* in the hobby that made me learn about heating a voice coil
> 
> Kelvin


Wait - Exactly how old are you


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## subwoofery

Randyman... said:


> 6 of one; half a dozen of another
> 
> 
> 
> Wait - Exactly how old are you


lol Just turned 30 :surprised: 

I can say whatever I want... This is the internet afterall 

Kelvin


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## I800C0LLECT

Part of what I took from this is that a smaller amplifier delivers a lot more distortion when pushed into clipping as well. So there's two problems in the picture, 1) sine wave like input and 2) more work/less cooling due to the higher distortion and noise floor.

Both of those would seem to allow more power to the coil without much of a break. Doesn't that mean it's easier to burn up a coil when pushing an amp too far? A speaker coil was designed to play with music, which is dynamic and not constant.


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## quality_sound

Distortion doesn't increase power. The size of the amplifier has nothing to do with its clipping characteristics.


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## I800C0LLECT

Maybe a lot of assumptions are being thrown around? I thought of this article in a sense of somebody using gain incorrectly. Mostly because almost every person I've ever helped points out right away that their sub sounds best when they turn the gain all the way up.

Doesn't a coil need to shed heat? If it's busy playing distortion or getting stressed out due to clipping, when will it get a chance to breathe? But I failed to mention my assumption of a poorly set gain.

I agree that if gains are set correctly I don't understand why an amplifier would hurt any speaker that's setup appropriately. But I usually only see people turn the gain up too much when using smaller amps.


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## minbari

quality_sound said:


> Distortion doesn't increase power. The size of the amplifier has nothing to do with its clipping characteristics.


depends on how you qualify "distortion" clipping is still distortion and it certainly does add power.


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## MarkZ

CDT FAN said:


> If you send your sub back for warranty because it burned out, the manufacurer can tell from the burn pattern on the voicecoil whether it had too much power or clipping.
> 
> Speaker Failure Analysis
> 
> 1. Black discolouration in the middle or all over the voice coil
> This is the most common damage seen and indicates that a well centred coil was driven with too much audio power for too long. The resistance of the burnt coil is often half or less the nominal value due to internal shorting.
> 
> 2. Black discolouration at one end of the voice coil.
> This is also a common sight and indicates either the voice coil was not centred during manufacture OR that the damage was caused by DC current rather than audio frequency current. A large DC current will displace the voice coil to one or other extreme. A faulty amplifier is automatically suspected.



I'm not sure what you're implying here, but DC offset has absolutely nothing to do with clipping.


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## MarkZ

I800C0LLECT said:


> Doesn't a coil need to shed heat? If it's busy playing distortion or getting stressed out due to clipping, when will it get a chance to breathe?


Coils don't breathe!  They also don't sweat, piss, ****, or anything else.

Coils also don't know what distortion is. They don't have access to the original (undistorted) waveform, so it is impossible for a coil to be affected by distortion. Distortion only affects human beings, because as humans we have the unique ability to have expectations about what something should sound like. So we're pretty damned good at identifying distortion. [actually, we're pretty bad at it, but sssshhhhhhhh!]

The only thing that coils "know" is how much energy they're being driven with, how much energy they were driven with a few seconds/minutes ago, what the frequency content of that energy is, and how hot or cold the local environment is. Those are the things that will determine whether your speaker will live or die.


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## CDT FAN

MarkZ said:


> I'm not sure what you're implying here, but DC offset has absolutely nothing to do with clipping.


I didn't write those notes. I copied them from the link that I included to illustrate my statement that the manufactures can tell from the burn patterns on the VC what kind of abuse that it encountered. I am learning and appreciate anybody's input or clarification. 

I remember reading on multiple occasions over the years about the effects of clipping and the damage it causes, but the article I referenced actually refuted those claims.

Since you mentioned it, doesn't DC offset affect clipping? In a simple amplifier, don't you want to bias a transistor at the midpoint of its linear range so that it can handle the positve and negative halves of the signal equally? If the bias is offset too little or too much, the transistor will cut off on the low end or saturate on the top end.


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## minbari

CDT FAN said:


> I didn't write those notes. I copied them from the link that I included to illustrate my statement that the manufactures can tell from the burn patterns on the VC what kind of abuse that it encountered. I am learning and appreciate anybody's input or clarification.
> 
> I remember reading on multiple occasions over the years about the effects of clipping and the damage it causes, but the article I referenced actually refuted those claims.
> 
> Since you mentioned it, doesn't DC offset affect clipping? In a simple amplifier, don't you want to bias a transistor at the midpoint of its linear range so that it can handle the positve and negative halves of the signal equally? If the bias is offset too little or too much, the transistor will cut off on the low end or saturate on the top end.


that is why most amplifiers are push-pull. you have 1 device baised positive and 1 baised negative. only 1 device is ever "on" at a time.

no matter what class you use, there the DC bias is NEVER on the output of the amplifier. more than a few mV of bias voltage at the output is rare.


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## CDT FAN

minbari said:


> that is why most amplifiers are push-pull. you have 1 device baised positive and 1 baised negative. only 1 device is ever "on" at a time.
> 
> no matter what class you use, there the DC bias is NEVER on the output of the amplifier. more than a few mV of bias voltage at the output is rare.


Oh, I see what you are getting at. That is if the DC bias is actually presented to the speaker. No, it shouldn't be directly flowing through the speaker. Just between the base and emitter of the transistor. However, it will indirectly affect the speaker output if it isn't adjusted properly.


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## quality_sound

I800C0LLECT said:


> Maybe a lot of assumptions are being thrown around? I thought of this article in a sense of somebody using gain incorrectly. Mostly because almost every person I've ever helped points out right away that their sub sounds best when they turn the gain all the way up.
> 
> Doesn't a coil need to shed heat? If it's busy playing distortion or getting stressed out due to clipping, when will it get a chance to breathe? But I failed to mention my assumption of a poorly set gain.
> 
> I agree that if gains are set correctly I don't understand why an amplifier would hurt any speaker that's setup appropriately. But I usually only see people turn the gain up too much when using smaller amps.


How does a speaker, any speaker know the difference between a clean signal and a distorted one? If the speaker is still oscillating then it's shedding heat regardless of the signal it's getting.



minbari said:


> depends on how you qualify "distortion" clipping is still distortion and it certainly does add power.


I see what you're saying, but I think of distortion as just that. I don't lump clipping into that because one is signal and the other is power. Related but a distorted signal is not necessarily clipped. Agreed that clipping adds power.


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## MarkZ

CDT FAN said:


> I didn't write those notes. I copied them from the link that I included to illustrate my statement that the manufactures can tell from the burn patterns on the VC what kind of abuse that it encountered. I am learning and appreciate anybody's input or clarification.


That's fine. I'm just trying to point out that when the second note talks about DC offset, it means that there was coil offset that resulted from a defective amplifier with a nonzero DC bias. This doesn't have anything to do with clipping... your post looked like you were trying to attribute those notes to clipping, that's why I responded. 



> I remember reading on multiple occasions over the years about the effects of clipping and the damage it causes, but the article I referenced actually refuted those claims.
> 
> Since you mentioned it, doesn't DC offset affect clipping? In a simple amplifier, don't you want to bias a transistor at the midpoint of its linear range so that it can handle the positve and negative halves of the signal equally? If the bias is offset too little or too much, the transistor will cut off on the low end or saturate on the top end.


Yup! DC of any sort will produce asymmetric clipping. But that would be the least of your problems if you had that much offset.



> Oh, I see what you are getting at. That is if the DC bias is actually presented to the speaker. No, it shouldn't be directly flowing through the speaker. Just between the base and emitter of the transistor. However, it will indirectly affect the speaker output if it isn't adjusted properly.


Don't confuse offset with bias. Bias can be adjusted to accommodate a particular design, but offset should always be as close to zero as possible. Some designs are intentionally overbiased into class A/B (out of laziness IMO ), but they should still produce an offset on the order of a few millivolts.


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## MarkZ

quality_sound said:


> I see what you're saying, but I think of distortion as just that. I don't lump clipping into that because one is signal and the other is power. Related but a distorted signal is not necessarily clipped. Agreed that clipping adds power.


This is a good point. It all gets down to semantics.

If you're comparing a signal that maxes out at 35v but isn't clipping vs. one that maxes out at 35v but IS clipping, the clipped signal will have *more* energy.

If you're comparing a signal that maxes out at 50v without clipping, but shove that SAME signal at the same amplitude level into an amp with 35v rails, the clipped signal will have *less* energy.

Clipping is a form of compression. Literally. If you buy a compressor, and set it to a hard knee with really fast attack, you're compressing the signal by clipping it.  So, in the real world, if you clip your signal, you're going to be giving the speaker LESS energy overall than you would if you had an amp with no limitations. 

The old motto was "clipping blows speakers". Maybe the new motto should be that clipping saves speakers. 

[the caveat here is when tweeters are on passive crossovers... then it's a different story]


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## CDT FAN

MarkZ said:


> That's fine. I'm just trying to point out that when the second note talks about DC offset, it means that there was coil offset that resulted from a defective amplifier with a nonzero DC bias. This doesn't have anything to do with clipping... your post looked like you were trying to attribute those notes to clipping, that's why I responded.
> 
> 
> 
> Yup! DC of any sort will produce asymmetric clipping. But that would be the least of your problems if you had that much offset.
> 
> 
> 
> Don't confuse offset with bias. Bias can be adjusted to accommodate a particular design, but offset should always be as close to zero as possible. Some designs are intentionally overbiased into class A/B (out of laziness IMO ), but they should still produce an offset on the order of a few millivolts.


Thanks for clarifying. I need to refresh my knowledge. I think my memory isn't what it use to be.


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## minbari

quality_sound said:


> I see what you're saying, but I think of distortion as just that. I don't lump clipping into that because one is signal and the other is power. Related but a distorted signal is not necessarily clipped. Agreed that clipping adds power.


I call anything distortion that"distorts"the signal. If the output doesn't follow the input, then it is distorted


Sent from my motorola electrify using digital farts


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## Bayboy

First time reading this and damn near got a headache trying to keep up with it. Guess I'm destined to damage my drivers since I'm upgrading to more power for headroom.... I give up.


----------



## quality_sound

You'll be fine. I regularly overpower the piss out of mine. It's not a bad thing.


----------



## chad

I wish I had the money to overpower the piss out of everything....

If you ain't flickering the clip light, you are wasting money on too much power.


----------



## Bayboy

My current amps don't have clipping indicators, but I would notice distortion before I reached driver limits. Then again my normal listening levels varies greatly so I felt a bit more power was in order.


----------



## I800C0LLECT

quality_sound said:


> How does a speaker, any speaker know the difference between a clean signal and a distorted one? If the speaker is still oscillating then it's shedding heat regardless of the signal it's getting.
> 
> 
> 
> I see what you're saying, but I think of distortion as just that. I don't lump clipping into that because one is signal and the other is power. Related but a distorted signal is not necessarily clipped. Agreed that clipping adds power.


I'm definitely just chiming in for the sake of learning. I'm not the best at conveying the thoughts in my head so I'm really using words out of context in a big way 

I had read another paper sometime back, don't recall where, that stated it's crucial to keep a clean signal going to the coil. So when I refer to distortion I was trying to imply a clipped signal.

So here's where I'm getting mixed up between the two sides...A clean signal can overwhelm a coil but so can a clipped signal....is all this coming down to the same thing as always; make sure you're only feeding the speaker what it can handle and use filters as needed? That's the art of this whole thing. Balancing install needs with what you have or will have vs. what you like. Holy crap...I get burned out reading this stuff sometimes.

So what everybody is getting into is whether it's the amp's fault or not? Hrmmm. Well this is probably where I just start watching again. I haven't burned one up yet. So I'm applying something right.


----------



## Bayboy

Applying something right, or limiting your setup's potential? Hmmm....


----------



## I800C0LLECT

Bayboy said:


> Applying something right, or limiting your setup's potential? Hmmm....


I used my DQS to set gains for quite a bit  But I totally see where you're going with that :>


----------



## Bayboy

Personally I've always matched power as close as possible, but this time I'm going for the extra headroom. Nothing worse than smelling your a/b amp on a long drive during the summer (I do push it to it's limits often). Haven't blown drivers or amps in a long time, but I don't like reaching power limits so soon. Will I reach driver limits now? Hmmm I don't know, but I'm hoping amp distortion won't be an issue. Two MRX-F30 on fronts (1 bridged on midbass), and a MRX-M100 on sub(s). Hoping this cures the headroom & heat issues, plus opens the door for more driver options. Perhaps I'm going in the wrong direction so I'm going to stay tuned to this thread.


----------



## ChrisB

chad said:


> I wish I had the money to overpower the piss out of everything....
> 
> If you ain't flickering the clip light, you are wasting money on too much power.


Ahh, the good old days of DJing with the Peavy CS amplifiers that felt like they weighed 100 pounds each. I used to run them with the VU meters bouncing into the DDT light.


----------



## chad

DDT is limiting, damn good limiting at that. Beats the **** out of Crown's ODEP... that's horrible ****.


----------



## quality_sound

I800C0LLECT said:


> I'm definitely just chiming in for the sake of learning. I'm not the best at conveying the thoughts in my head so I'm really using words out of context in a big way
> 
> I had read another paper sometime back, don't recall where, that stated it's crucial to keep a clean signal going to the coil. So when I refer to distortion I was trying to imply a clipped signal.
> 
> So here's where I'm getting mixed up between the two sides...A clean signal can overwhelm a coil but so can a clipped signal....*is all this coming down to the same thing as always; make sure you're only feeding the speaker what it can handle and use filters as needed?* That's the art of this whole thing. Balancing install needs with what you have or will have vs. what you like. Holy crap...I get burned out reading this stuff sometimes.
> 
> So what everybody is getting into is whether it's the amp's fault or not? Hrmmm. Well this is probably where I just start watching again. I haven't burned one up yet. So I'm applying something right.


Exactly. It's ALL about power and not exceeding your drivers' limits.


----------



## Randyman...

chad said:


> DDT is limiting, damn good limiting at that. Beats the **** out of Crown's ODEP... that's horrible ****.


Gotta love Jack Sondermeyer and his bullet proof designs! I attended two of the Peavey Advanced Sound Reinforcement 5-day seminars in Meridian Mississippi back in the 90's - got to meet and learn from all kinds of awesome engineers @ Peavey. They really do get a bad wrap IMO (sometimes they might deserve it, but only from a "cheap is good / poor musician" angle). I still despise their lack of any sub-40Hz response in most of their subs :mean: When I asked one of their PA Speaker designers why they simply cut holes in a baffle and call it a "Port", he stated the 3/4" thickness of the baffle WAS the port length!!!  This was for an SP2 "Main" speaker, but still - a 3/4" long port???!!!!??? I guess it works for their relatively high f3/fb response in exchange for extra efficiency...

I'm still rocking some older SP2XT's and Impulse200's, and have a few CS800x's in storage.


Back on topic: I like how MarkZ recapped this - that should clear up anyone's misunderstandings about clipping and RMS power IMO.

And his "[the caveat here is when tweeters are on passive crossovers... then it's a different story]" statement is spot on wrt my previous comments on how/why clipping can kill tweets more easily than a woofer (in a passive full-range system).


----------



## chad

While you were in Meridian did you do any partying with Max? He's a good time. I spent a bunch of time down there too. Did a LOT of peavey service and was one of the few that did mass repairs on the DPC stuff. Can still repair those damn things in my sleep.

It was not uncommon to use a "hole" for the vent. Hell, I designed an enclosure recently that never transpired that had just the same thing. Looked damn good on paper too.

Not many pro subs go much below 40, the Q-Wave stuff does now.... Not much below. Hell, the SP series subs did not get much below 50!

I worked a bit in the field development of the BWX series. Broke 4 at a time without the coil looking anything but brand new. Then they got the suspension issues worked out


----------



## Randyman...

OK - A little more OT!


chad said:


> While you were in Meridian did you do any partying with Max? He's a good time. I spent a bunch of time down there too. Did a LOT of peavey service and was one of the few that did mass repairs on the DPC stuff. Can still repair those damn things in my sleep.
> 
> It was not uncommon to use a "hole" for the vent. Hell, I designed an enclosure recently that never transpired that had just the same thing. Looked damn good on paper too.
> 
> Not many pro subs go much below 40, the Q-Wave stuff does now.... Not much below. Hell, the SP series subs did not get much below 50!
> 
> I worked a bit in the field development of the BWX series. Broke 4 at a time without the coil looking anything but brand new. Then they got the suspension issues worked out


"Max" rings a bell - it was in the mid 90's. Our regional Peavey Rep came down there with me - can't remember his name ATM. I remember Marty McCann (spelling) giving most of the lectures. Spent a lot of time in the fish bowl and auditorium jamming, too 

Agreed on the SP118 subs - useless below 50Hz  Their BW suspensions always seemed to be a limiting factor to me, too. The coils can take the power for sure, and they make a killer "Woofer" - but Peavey makes their compromises - they rob Peter (low bass) to pay Paul (efficiency and low cost). I much prefer my JBL 2241G's where Peter and Paul both end up rich (by robbing *my* wallet!)  Peavey's BWX and Low Riders seem to be a step in the right direction. It's cool that you were involved with their development IMNSHO...

Back to the "Power" talk :smash:


----------



## Dillyyo

Just a closing article on the subject matter for those looking for more clarity. Where I first learned about it, as I am sure many others. Sourced from A2000 tech briefs:

http://www.monsterproducts.com/mpc/stable/tech/A2420_Some_Facts.pdf


----------



## Randyman...

Dillyyo said:


> Just a closing article on the subject matter for those looking for more clarity. Where I first learned about it, as I am sure many others. Sourced from A2000 tech briefs:
> 
> http://www.monsterproducts.com/mpc/stable/tech/A2420_Some_Facts.pdf


Odd - I'm not sure if I agree with all of R.C.'s findings with regard to clipping and how the energy is dispersed through the octaves. He appears to be talking about clipping a single low-frequency sinewave, and is not taking into account clipping complex full-range waveforms. He seems to suggest that clipping a full-range system WILL NOT blow tweets - but we know that is not the case.

JBL certainly states otherwise:

http://www.jblpro.com/pub/technote/lowpower.pdf

I dig and respect R.C. and all, but I'll believe JBL/Harmon (and my own Live Sound experience) well before some car audio buff  

And even though the clipped harmonics are distributed throughout the frequency range, when you clip a sub amp that's actively crossed, ALL of this energy still goes to the Woofer's coil (the woofer has no passive x-over to filter this energy out). Plus the much higher "duty-cycle" of the clipped waveform further increases RMS Power...


----------



## chad

http://www.adx.co.nz/techinfo/audio/note128.pdf


----------



## Randyman...

That makes more sense IMO. So it's mainly that the full-range amp can keep increasing the HF content's power (since it is already relatively small compared to the bass) when the user is slamming the low-frequency spectrum into clipping. As long as the woofer can handle the total RMS heat of the clipped amp (generally a max of 2x clean rated RMS power), the woofer will keep on chugging just fine (but sound like ass). That combined with the small increase in harmonics due to clipping the woofer, and your tweets are toast just as JBL mentioned above...


----------



## chad

Yup, just wanted to toss it in there.

Peeps gotta understand that the examples of clipping that are shown are GROSS examples, not a flicker or a waveform hitting the rail real quick like but rather SLAMMING the rails.


----------



## Dillyyo

Randyman... said:


> Odd - I'm not sure if I agree with all of R.C.'s findings with regard to clipping and how the energy is dispersed through the octaves. He appears to be talking about clipping a single low-frequency sinewave, and is not taking into account clipping complex full-range waveforms. He seems to suggest that clipping a full-range system WILL NOT blow tweets - but we know that is not the case.
> 
> JBL certainly states otherwise:
> 
> http://www.jblpro.com/pub/technote/lowpower.pdf
> 
> I dig and respect R.C. and all, but I'll believe JBL/Harmon (and my own Live Sound experience) well before some car audio buff
> 
> And even though the clipped harmonics are distributed throughout the frequency range, when you clip a sub amp that's actively crossed, ALL of this energy still goes to the Woofer's coil (the woofer has no passive x-over to filter this energy out). Plus the much higher "duty-cycle" of the clipped waveform further increases RMS Power...


IMO you are misinterpreting what RC is saying. He said it is seldom the case, implying infrequent occurrence, not omission of occurrence. Likely due to his implied assumption of proper application. Nevertheless, The Rane article and JBL articles agree with exactly as what Richard's data indicated...that excessive power from an x level of clipped signal, _can_ damage tweeters. RC just seems to assume that the tweeter will be properly applied and set up in a system, so there is no reason to experience full amp saturation. 

Rane and JBL have an interest in expressing the information in the manner they did. I don't see the interest for RC. Everything in the tech brief if reproducible and verifiable. So are the other white papers, but they are generalized discussions where RC provided more specificity with his conclusion.

I've never had a problem with smoking tweets and I set my systems up with clipping every time.


----------



## Dillyyo

Randyman... said:


> That makes more sense IMO. So it's mainly that the full-range amp can keep increasing the HF content's power (since it is already relatively small compared to the bass) when the user is slamming the low-frequency spectrum into clipping. As long as the woofer can handle the total RMS heat of the clipped amp (generally a max of 2x clean rated RMS power), the woofer will keep on chugging just fine (but sound like ass). That combined with the *small increase in harmonics due to clipping the woofer, and your tweets are toast* just as JBL mentioned above...


I don't see how that's possible if your tweeters have proper filters in place. Again, if you are fully saturating the channels that feed your tweeters, creating an excessive clipped state, then this only seems to point to inadequate application. 

If you're not clippin' ur just trippin'. lol


----------



## Golden Ear

Found this thread looking up "headroom". The concept just doesn't make sense to me. Aren't your speakers going to distort at the same wattage whether its from a 100 wpc amp or a 200 wpc amp? For example, if the speakers are rated at 60 wpc and they distort at 80 wpc, wouldn't a 200 wpc amp be pointless? I'm probably oversimplifying it or I just have it all wrong, but can someone please explain? I'd really like to know if I should buy that 200 wpc amp


----------



## Bayboy

Buy the bigger amp because you can, because you won't be satisfied until you have seen the results for yourself, because you will trade speakers like underwear sooner or later and having more power means you can try a larger variety of speakers.


----------



## I800C0LLECT

I'd like to bring focus back to the article vs. the subtleties we're slowly introducing....



> *you can never have too much power*... ...*Little amplifiers driven into clipping burn out speakers.*


Obviously there's a lot of variables to mention, debate, or argue...but I don't see anything wrong with the conclusion?

Drive a small amp into clipping hoping for something amazing; well, you'll get something amazing  I don't think it means just a little flicker either...I think it's talking about grandma's boy messing with his 16th birthday present.


----------



## Bayboy

I thought the variables was plain to see, just that some went on a tangent which diverted the flow of things. Basically, you're better off with a bigger amp under control than a smaller amp driven beyond it's limits given that it's clipped power is still enough to overdrive the speaker. Correct?


----------



## quality_sound

If, and only if, the clipped signal has too much power for the driver in question. Otherwise clipping, other than sounding bad, won't make a difference.


----------



## Bayboy

quality_sound said:


> If, and only if, the clipped signal has too much power for the driver in question. Otherwise clipping, other than sounding bad, won't make a difference.


That's what I gathered. Then filtering (active/passive) became a part of the equation, but it still makes sense.


----------



## MarkZ

I800C0LLECT said:


> Obviously there's a lot of variables to mention, debate, or argue...but I don't see anything wrong with the conclusion?


You need to read the thread...


----------



## CDT FAN

Bayboy said:


> Buy the bigger amp because you can, because you won't be satisfied until you have seen the results for yourself, because you will trade speakers like underwear sooner or later and having more power means you can try a larger variety of speakers.


My thinking is inline with yours. A larger amp leaves room to grow and it isn't going to damage anything is you use restraint. I'd rather have clean sound than have an amp that is straining and starts to sound harsh when it is reaching its limit. Even though the average power being used isn't much, the peaks in music can be many times greater. As an example, the LED meters on my home reciever go to 200 watts. If I have it cranked up pretty good, the average power being used may only be a few watts, but the 200 watt lights flicker from time to time.


----------



## MarkZ

Everyone wants amps that are a bazillion watts, have small footprints, cost only a few bucks, and don't draw any current from the electrical system. But that doesn't really help anyone make decisions about what to buy. The power discussion is VERY relevant. Because the reality is that most people *DO* clip some of their channels some of the time, so it's important to know what it means and whether it's important to spend extra and dedicate more space to other/bigger amps.


----------



## Golden Ear

MarkZ said:


> Everyone wants amps that are a bazillion watts, have small footprints, cost only a few bucks, and don't draw any current from the electrical system. But that doesn't really help anyone make decisions about what to buy. The power discussion is VERY relevant. Because the reality is that most people *DO* clip some of their channels some of the time, so it's important to know what it means and whether it's important to spend extra and dedicate more space to other/bigger amps.


That's what I'm saying. If your speakers clip at 80 wpc then won't a 100 wpc amp suffice? Wouldn't a 200 wpc amp be wasted? Obviously there's the 'ability to change gear factor' to consider. But, what if you aren't going to change anything? Doesn't that make the "headroom" point mute?


----------



## MarkZ

Yup, I agree. I also don't understand the people who change gear all the time. Either people are incredibly bored, or they're not doing it right the first time.


----------



## minbari

its the "green is greener on the other side" syndrome. you have a nicely set up system but you just know that is you replace the tweeters with X brand it will sound 100x better.


----------



## Bayboy

Or you could be like me and want a simple upgrade that has more flexibility and more power over dinosaur amps that are bulky and limited on power. But I suppose that doesn't put that in the constantly trading category... 

However, I'm sure bad decisions as well as forum boners account for most. Heck it took me I don't know how many years to finally switch to an all class D setup while I've sat back and watch a lot of these guys go through them like soiled underwear.


----------



## quality_sound

Golden Ear said:


> That's what I'm saying. If your speakers clip at 80 wpc then won't a 100 wpc amp suffice? Wouldn't a 200 wpc amp be wasted? Obviously there's the 'ability to change gear factor' to consider. But, what if you aren't going to change anything? Doesn't that make the "headroom" point mute?


Speakers don't clip.


----------



## Golden Ear

quality_sound said:


> Speakers don't clip.


Distort?


----------



## I800C0LLECT

MarkZ said:


> You need to read the thread...


What did I misunderstand?

I thought the assumption is that clipping provides potential for higher average power vs a clean signal over a period of time?...

hrmmm. I miss something?


----------



## minbari

I800C0LLECT said:


> What did I misunderstand?
> 
> I thought the assumption is that clipping provides potential for higher average power vs a clean signal over a period of time?...
> 
> hrmmm. I miss something?


power is power. that is the beauty of power. I think what most people are saying that if you are not setting your amplifiers up for some clipping, then you are leaving alot of the amplifier's potential on the table.

if you are using a 300 watt amplifier channel and only driving it to 100watts, then the speakers are seeing 100 watts. if you have a 75watt channel and driving it to 100 watts with clipping, the speaker still sees 100 watts.

the difference is how much you paid for each amplifier.


----------



## Bayboy

Not enough to be anal about if it is used... 

But seriously, I'd rather experiment with different drivers periodically than to keep switching amps so getting one with enough power to be flexible only makes sense. Now if you keep switching amps to suit every driver you play with then that would be more wasteful than having extra power you don't use IMO.


----------



## subwoofery

I'm with Chad on this one... If you're not litely clipping the output of your amp, you're wasting money on a bigger amp... 
If the owner of "big meat" is satisfied with the dynamics of a single Arc Audio 4150XXK to power his whole system, others should also be satisfied if they set their gains right  
http://www.diymobileaudio.com/forum/build-logs-project-install-gallery/144203-uncle-audio-has-been-brewwin-up-some-tasties-his-own-sbn-debut.html

Kelvin


----------



## Bayboy

Who or what is Big Meat?? That link went to a thread about Win ISD.


----------



## quality_sound

Big Meat is Steve Head's car.


----------



## MarkZ

I800C0LLECT said:


> What did I misunderstand?
> 
> I thought the assumption is that clipping provides potential for higher average power vs a clean signal over a period of time?...
> 
> hrmmm. I miss something?


Yeah, post #37.


----------



## Bayboy

So Mark are you basically saying that reaching clipping should be used as a indicator that you have reached your system's limits as long as power and handling is matched and set not to burn up the drivers?


----------



## MarkZ

I don't believe in the concept of setting your amplifier to not burn up drivers. If you have a problem burning up drivers, you're using the wrong drivers for the job. A properly designed system should be designed to withstand the output level requirements that you need.

If your problem is blowing speakers, you have three options.
1) turn the volume down
2) use drivers that can handle more power
3) restrict the bandwidth that the driver is asked to play (e.g. ask your larger drivers to pick up the slack by shifting your crossover points).

All I'm saying is that yes, clipping will deliver more power to the speakers than if you turned the volume knob down to the point where it didn't clip... DUH.  Overdriving your amp will produce higher power than not overdriving the same amp. But everybody knows that.

The true comparison is whether your drivers would have lived if you had a bigger amp that didn't clip. The answer to that question is a resounding *no* (again, with the exception of passive tweeters and other delicate high freq drivers...).


----------



## MarkZ

BTW, I *hate* that DIYMA inserted web links in my post. They're indistinguishable from when I post real links embedded in the text. Please don't click the links in the post above ^^^.


----------



## Bayboy

MarkZ said:


> I don't believe in the concept of setting your amplifier to not burn up drivers. If you have a problem burning up drivers, you're using the wrong drivers for the job. A properly designed system should be designed to withstand the output level requirements that you need.
> 
> If your problem is blowing speakers, you have three options.
> 1) turn the volume down
> 2) use drivers that can handle more power
> 3) restrict the bandwidth that the driver is asked to play (e.g. ask your larger drivers to pick up the slack by shifting your crossover points).
> 
> All I'm saying is that yes, clipping will deliver more power to the speakers than if you turned the volume knob down to the point where it didn't clip... DUH.  Overdriving your amp will produce higher power than not overdriving the same amp. But everybody knows that.
> 
> The true comparison is whether your drivers would have lived if you had a bigger amp that didn't clip. The answer to that question is a resounding *no* (again, with the exception of passive tweeters and other delicate high freq drivers...).


Okay... now that puts things more in place.


----------



## Dillyyo

Bayboy said:


> Not enough to be anal about if it is used...
> 
> But seriously, I'd rather experiment with different drivers periodically than to keep switching amps so getting one with enough power to be flexible only makes sense. Now if you keep switching amps to suit every driver you play with then that would be more wasteful than having extra power you don't use IMO.


Why would one need to keep switching amps to suit different speakers?! How much extra power do you think that 200 watt amp is going to provide you over the 100 watt amp you currently own? Seems like we have gotten way off target with the main point in dispute:

"clipped" sound waves DO NOT cause damage to speakers themselves. Excessively "clipped" sound waves, which contain significantly more power output than their "non-clipped" or "lightly clipped" sound waves, is what can lead to thermal or mechanical failure in a speaker. This is obviously dependent upon the power of the amp in question, since fully saturating and "clipping" a 1 watt amp will do nothing to any speaker, tweeter or otherwise, that is playing that clipped signal.


----------



## Dillyyo

I800C0LLECT said:


> What did I misunderstand?
> 
> I thought the assumption is that clipping provides potential for higher average power vs a clean signal over a period of time?...
> 
> hrmmm. I miss something?


That assumption only holds true if we are talking about the same amp providing the clean and clipped signal. That might have been implied by you, but it wasn't clear so I clarified.


----------



## Dillyyo

Golden Ear said:


> Found this thread looking up "headroom". *The concept just doesn't make sense to me. Aren't your speakers going to distort at the same wattage whether its from a 100 wpc amp or a 200 wpc amp?* For example, if the speakers are rated at 60 wpc and they distort at 80 wpc, wouldn't a 200 wpc amp be pointless? I'm probably oversimplifying it or I just have it all wrong, but can someone please explain? I'd really like to know if I should buy that 200 wpc amp


This would have to assume that the speakers resistance stays constant, which we know is not the case. Put100 watts of power to a sub playing sine waves at the subs resonant frequency and then do the same with sine waves playing 2 octaves north of that and see which sounds like it distorts more. 

With that said, with amplifiers you should always buy the amp that gives you the most power for the dollar. Obviously quality build and things like that come into play, but in general you should always get the most bang for the buck when it comes to amps. Headroom is always a huge plus, not the fact that one doesn't want their amp to clip at all.


----------



## Dillyyo

I800C0LLECT said:


> I'd like to bring focus back to the article vs. the subtleties we're slowly introducing....
> 
> 
> 
> Obviously there's a lot of variables to mention, debate, or argue...but I don't see anything wrong with the conclusion?
> 
> Drive a small amp into clipping hoping for something amazing; well, you'll get something amazing  I don't think it means just a little flicker either...I think it's talking about grandma's boy messing with his 16th birthday present.


The first part of that highlighted statement is correct, but the second is flat out wrong and completely disingenuous.


----------



## I800C0LLECT

MarkZ said:


> Yeah, post #37.


Ah ok. I thought the article implied that more power was being sent to the speaker in his scenario of a clipped signal.

I never disagreed with post #37. I just thought you were throwing that out there as a caveat in case people didn't understand. Didn't realize that was the actual debate. My bad!!


----------



## Golden Ear

subwoofery said:


> I'm with Chad on this one... If you're not litely clipping the output of your amp, you're wasting money on a bigger amp...
> If the owner of "big meat" is satisfied with the dynamics of a single Arc Audio 4150XXK to power his whole system, others should also be satisfied if they set their gains right
> http://www.diymobileaudio.com/forum/build-logs-project-install-gallery/144203-uncle-audio-has-been-brewwin-up-some-tasties-his-own-sbn-debut.html
> 
> Kelvin


Is the "lite clipping" you are referring to audible as distortion or in any other way? 

I agree with your statement about wasting money on a bigger amp as a 75 wpc amp driving my components plays louder than I ever listen to it. Truthfully, I think a 50wpc amp is plenty of power but we all want the biggest and best money can buy. 

I'm just trying to justify not buying that Zapco z150.6 I really want, if you guys haven't noticed


----------



## subwoofery

Golden Ear said:


> Is the "lite clipping" you are referring to audible as distortion or in any other way?
> Shouldn't be audible since you'll be litely overdriving the output on dynamic peaks only - so it shouldn't sound like a really bad distortion sound that some driver can exhibit...
> 
> I agree with your statement about wasting money on a bigger amp as a 75 wpc amp driving my components plays louder than I ever listen to it. Truthfully, I think a 50wpc amp is plenty of power but we all want the biggest and best money can buy.
> I have a HU powered system right now and for now, it works quite well :blush: BUT...
> 
> I'm just trying to justify not buying that Zapco z150.6 I really want, if you guys haven't noticed
> I don't care about what *I* say, I love big and powerful amps and don't care what people tell me - I would buy that Z150.6
> I have a sweet thing for amps - more so than drivers even though amps are "less" important than good drivers for a great system.


The opinion I expressed in my first post still stands though... No lite clipping = wasting power

Kelvin


----------



## Golden Ear

Thanx Kelvin. I too have a sweet thing for amps over other parts of the system


----------



## shayne32*

good read, thanks for the insight


----------



## Oliver

MarkZ said:


> This is a good point. It all gets down to semantics.
> 
> If you're comparing a signal that maxes out at 35v but isn't clipping vs. one that maxes out at 35v but IS clipping, the clipped signal will have *more* energy.
> 
> If you're comparing a signal that maxes out at 50v without clipping, but shove that SAME signal at the same amplitude level into an amp with 35v rails, the clipped signal will have *less* energy.
> 
> *Clipping is a form of compression. * Literally. If you buy a compressor, and set it to a hard knee with really fast attack, you're compressing the signal by clipping it.  So, in the real world, if you clip your signal, you're going to be giving the speaker LESS energy overall than you would if you had an amp with no limitations.
> 
> The old motto was "clipping blows speakers". Maybe the new motto should be that clipping saves speakers.
> 
> [the caveat here is when tweeters are on passive crossovers... then it's a different story]


Why Modern CD's Sound So Bad - YouTube



> People want good dynamic music, *not over-compressed-ear-fatiguing-*****.*


----------



## Golden Ear

Very insightful video. Thanks for posting it, Oliver. Which of those two CDs in the video does music downloaded from iTunes compare to?


----------



## ryan roberts

clipping may not blow speakers, but it definately blows to listen 2..


----------



## minbari

ryan roberts said:


> clipping may not blow speakers, but it definately blows to listen 2..


Depends on how much and what freq.

Sent from my motorola electrify using digital farts


----------



## ryan roberts

true.. its true that if u want to get the Max output potential from your amp, u are inevitably going to have ur output signal surpass ur supply voltage, when that happens u will clip the signal,its almost inaudible on some amps as long as the hangover isn't to long, but during that period of hangover the amps notreproducing the source material and is adding harmonic content, too much clipping effects transparency, imaging and gives u ear fatigue...


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## ryan roberts

I apologize! ..I should have said that is my understanding..


----------



## Fricasseekid

It really bothers me that when I reach over to crank that volume knob one more click to the right again and again, I feel like I'm looking for a certain level of "loudness" when what I'm really after is distortion. 

How do we train our ears to be satisfied with clean, loud, distortion free music?

I may start a new thread to ask this.


----------



## therapture

Dillyyo said:


> Why would one need to keep switching amps to suit different speakers?! How much extra power do you think that 200 watt amp is going to provide you over the 100 watt amp you currently own? Seems like we have gotten way off target with the main point in dispute:
> 
> *"clipped" sound waves DO NOT cause damage to speakers themselves. *Excessively "clipped" sound waves, which contain significantly more power output than their "non-clipped" or "lightly clipped" sound waves, is what can lead to thermal or mechanical failure in a speaker.* This is obviously dependent upon the power of the amp in question, since fully saturating and "clipping" a 1 watt amp will do nothing to any speaker, tweeter or otherwise, that is playing that clipped signal*.



As in, all the peeps that run around with stock HU power on stock speakers, clipping the **** out of them and the speakers sounding like *******, because they are trying to keep up with the 1200w "max power" sub amplifier, also clipping the **** out of a pair of 12's.


----------



## therapture

Fricasseekid said:


> It really bothers me that when I reach over to crank that volume knob one more click to the right again and again, I feel like I'm looking for a certain level of "loudness" when what I'm really after is distortion.
> 
> How do we train our ears to be satisfied with clean, loud, distortion free music?
> 
> I may start a new thread to ask this.




I feel this pain. Coming from a basshead background...sometimes I KNOW I am overdriving my speakers, especially the mids, and I like it 

I am about 80% SQ now, with a side serving of bass (but loud, clean bass).


----------



## Oliver

As audio/video hobbyists, most of us grew up thinking that if we have an amplifier with 50 watts of rated output power into 8-ohm speakers, and that combination produces reasonably clean and loud music, then by doubling the amplifier power to 100 watts per channel, the system would then play twice as loud. Many readers likely still believe that.* Not so.*

Although it's not the easiest thing to comprehend, doubling the amplifier power does not double the loudness. In the above example, *the sound from the speakers would not be "twice as loud"*; it would only be "a little louder," an increase of 3 decibels. How loud is that? Hearing tests with large groups of people have revealed that a one-decibel (1 dB) change in loudness is approximately the smallest audible step that the average listener can detect, so an increase of 3 dB most listeners term "slightly louder."

NO ****E !


----------



## oldschoolbeats

Thunderplains said:


> Excellent info.. So now that I know my listening needs.. I need to get 5 of these amps..
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 4 altenators, rip out the backseat and fill with batteries and I will achieve my listening levels desired.. :coolgleamA:


.15 distortion and 69 signal to noise? wowza.... i remember even when crappy amps topped out at like .03


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## WinWiz

The VC gets cooled by air when its moving back and forth playing music.
A badly clipped signal makes the vc stand still, for a very short time, in outer and/or inner position. So with a lot of clipping the the vc gets lots power but less cooling, therefore driving small amps into clipping can hurt a speaker!

I once heard or read that small home audio amps with bass and treble adjustment knobs made the problem worse, but I think thats probably because bass boost makes the amp clip more..?

And yeah the specs of the Hertz amp looks to be all about SPL, I assume its not a full range amp maybee class d sub amp? 
I think my 20 year old (and small) rockford amps beat the Hertz on anything but total power and maybe effectiveness...


----------



## squeak9798

WinWiz said:


> The VC gets cooled by air when its moving back and forth playing music.
> A badly clipped signal makes the vc stand still, for a very short time, in outer and/or inner position. So with a lot of clipping the the vc gets lots power but less cooling, therefore driving small amps into clipping can hurt a speaker!
> .


Old wives tale. Average power over time is the only thing that matters.


----------



## cajunner

eh, here's an observation:

every time I've blown a speaker, I was clipping the crap out of it.

that sure doesn't seem like I'm saying anything at all, but realize that I have never blown a speaker with clean undistorted power.

I've never had enough clean undistorted power to be able to just pour on the heat and watch it fry, because I've always erred on the side of caution.

The more I thought about it, the more sense it made. I wouldn't put 350 watts of clean power into a speaker designed for 100 watts of RMS, or continuous because I was afraid of blowing it, but I'd put a 100 watt amp on it, and clip the thing until pop!

so let that be a lesson.

It's not power that kills speakers, but the will to power, hahaha...


----------



## WinWiz

squeak9798 said:


> Old wives tale. Average power over time is the only thing that matters.


So you do not believe the vc get cooled by moving air? Or you just dont believe that a speaker trying to reproduce a very clipped signal moves less compared to same volume from a clean signal?

I actually got this info from a dynaudio engineer. And I like the sound of his speakers so dont think hes a complete idiot...

And if you look at a very clipped signal on a scope its kind of like a ac/dc mix, to me thats obviously not healty for speakers!


----------



## squeak9798

WinWiz said:


> So you do not believe the vc get cooled by moving air? Or you just dont believe that a speaker trying to reproduce a very clipped signal moves less compared to same volume from a clean signal?
> 
> I actually got this info from a dynaudio engineer. And I like the sound of his speakers so dont think hes a complete idiot...
> 
> And if you look at a very clipped signal on a scope its kind of like a ac/dc mix, to me thats obviously not healty for speakers!


Of course speakers get cooled by motion. The myth is that the shape of the waveform is what causes the damage. It's not. It's average power over time. With a 60hz signal, for example, the coil is still moving back & forth 60 times per second. There is still a significant amount of cooling occurring. Then factor in the coil inductance and the fact that the inductance is going to limit the rise time and filters out a portion of the harmonics generated by the clipping, so those sharp edges you see on a scope aren't going to be sharp edges in the movement of the coil. There's no DC in a clipped signal, it's all AC.

I don't think he's a complete idiot either. But the information you have on what damages a loudspeaker is incorrect. It's the average power over time, not the shape of the waveform, that causes damage. The shape of the waveform may increase distortion so it won't sound wonderful, but it's not damaging unless the average power exceeds the thermal capabilities of the coil. And that's what clipping does. It increases the average power over time.


----------



## WinWiz

In my life I have only blown one speaker...
This was a Jamo Classic 4 (100rms) driven by a cheap kenwood 2x60 RMS amp, about 20 years ago...
The blown unit was replaced and I sold the speakers to a friend with a nice 2x90 RMS NAD. My friends is the kind of guy who can and will destroy almost anything but to this day the Classic 4 is still running strong despite many techno parties at loud volume!

I do know a clipped signal is not DC but the flat top and bottom you se on a clipped wave is alot like DC, the amp is asking the driver to temporarily stand still in outer or inner positions.
The argument that at 60hz the coil is still moving back & forth 60 times per second is true BUT when the signal is severely clipped the speaker moves like this: moving out, short pause (caused by the flat top of the clipped wave), moving in, short pause (caused by the flat bottom of the clipped wave) and so on. This cools lees than just moving in and out without the small delay at top and bottom, and this is why a clipped signal at 100watt is more dangerous for the speakers than the same (but unclipped) 100watt signal from a stronger amp...

If the vc inductance limit the rise time and filters out a significant part of the harmonics generated by clipping they can't be high sound quality drivers, cause quality drivers shall by definition not filter anything out, but reproduce the signal truthfully as it is!
If I on purpose wanted to replay a clipped signal just to hear what it sounds like I sure wouldn't like my speakers to filter out the sound! 

Im not saying a clipped 10watt signal will instantly fry a 50watt speaker but if you are at the edge of your drivers thermal limit, a severly clipped signal can potentially damage speakers. 

So I guess we will just have to disagree on that one!

PS: The 2x60 kenwood wasn't defective its still running fine but as a kitchen amp!


----------



## Treesx4

From what I've read in my insomnia laced night.... Everyone has brought some very good points... But it seems the clipped signal = blown speakers is a good one.... Winwiz and others are correct.... the speaker is designed to follow the signal... It has to... If the signal is clipped ( I'm talking hard clipped, high output ) it will go from moving just like the signal,,,smoothly...sign wave, to pausing at the clipping point,,, square wave... now speakers are moving very fast,duh, and we are talking about mili seonds at best.... BUT think this way.... EXAMPLE...I know we all have used batteries to "pop" while checking speakers or for polarity.... would you hold a AA battery to that speaker??? Probably with no problem... Now 18v drill battery, or 12v car battery??? I wouldn't hold it for long... that's the problem with clipping is the more clipped the more the wave is cut flat.... the longer its held at THAT point... Would you hold a AC or DC motor ( eg... fan or starter) still and then turn it on while still keeping it still.... Nope it will burn it up.... Speakers, fans, starters, or transducers... are all the same electricity wise they want to MOVE smoothly.... If your system is well thought out x'd over at the right points.... YOU will be better off with more power than not enough evey time.... How many engines in a auto have been blown up with the go pedals on the floor vs on cruise control just hwy speeds??? Ive been in this hobby for 3 decades and we used to argue this crap in the instal bays or at shows, Im getting older and learning the forum stuff...because of that I usually don't reply on forums... so its hard for me to get my points across and I'm not trying to be an ass... But its these debates that makes us all better.... I'm very happy I found DIY MOBLE audio.....


----------



## cajunner

check this out:

I have recently been inducted into the queue of induction plate cooking.

(hah!)

so, let's remember that power in, doesn't equal acoustic power out. 

and that a voice coil is an inductor that you put electricity into.

the efficiency of that coil to transfer the electrical energy to acoustic energy is somewhat less than 5% for even some of the best drivers.

that means that 95% of that energy is dissipated as heat.

now, let's enter the induction cooker theory.

that coil, is going to be releasing 95% of it's energy in some way, through heat.

I propose, that when a speaker is "stuck" in the clipped waveform, it's spending a lot more time in that one area at the top and the bottom of the waveform, and that's where the heat is being inductively coupled to the pole piece and top plate gap.

the coil is acting like an induction stove's coil, it's heating up the surrounding ferrous metal parts that are activated by the induction energy transfer.

so, when it's moving normally the coil distributes the inductive energy more or less, evenly.

when it's clipping, it's distributing the energy at the top and bottom of the coil's travel, over a longer time period, which leads to those places getting more energy than before, without clipping.


so, as the surrounding structures heat up, this also raises the temperature of the coil itself, causing the glues to soften, the former to warp, the copper itself to expand and delaminate from the former.

all signs of heat damage, that is the result of clipping energy being distributed unevenly by the induction process at the top and bottom of the waveform.

how's that for blow your mind?


haha.


that 95% of energy, in watts going someplace, means that it's no joke that a motor needs to dissipate heat, and motors that can't shed heat will fail.


maybe someone can disprove this hypothesis, but I think we're on a track now...


----------



## Treesx4

insomniac mind blown!!!  I'm just so glad thats my point just better !!! Very well put.... Trust me after all the years of being in the 12 volt industry I've seen more problems with speakers driven off the HU than any thing.... 

P.s. those cooking thingy is KICK,A...


----------



## squeak9798

WinWiz said:


> In my life I have only blown one speaker...
> This was a Jamo Classic 4 (100rms) driven by a cheap kenwood 2x60 RMS amp, about 20 years ago...
> The blown unit was replaced and I sold the speakers to a friend with a nice 2x90 RMS NAD. My friends is the kind of guy who can and will destroy almost anything but to this day the Classic 4 is still running strong despite many techno parties at loud volume!


Cute story. Glad your friend is still enjoying the speakers. But unfortunately doesn't prove anything.



> I do know a clipped signal is not DC but the flat top and bottom you se on a clipped wave is alot like DC, the amp is asking the driver to temporarily stand still in outer or inner positions.
> The argument that at 60hz the coil is still moving back & forth 60 times per second is true BUT when the signal is severely clipped the speaker moves like this: moving out, short pause (caused by the flat top of the clipped wave), moving in, short pause (caused by the flat bottom of the clipped wave) and so on. This cools lees than just moving in and out without the small delay at top and bottom, and this is why a clipped signal at 100watt is more dangerous for the speakers than the same (but unclipped) 100watt signal from a stronger amp...


Not really how it happens in a system that has a lowpass filter. And speakers do, inherently. The amount of cooling occurring is virtually identical. The difference is higher average power over time for the clipped signal.

95Honda did a test many years ago on SI.N that tested exactly this. There was no significant difference in the failure time of a driver when driven with a sine wave and a squarewave of the same average power. 

Also, this has already been beaten to death on this forum: http://www.diymobileaudio.com/forum/general-car-audio-discussion/87065-underpowering-sub-4.html

Power is what kills drivers, not waveform. 



> If the vc inductance limit the rise time and filters out a significant part of the harmonics generated by clipping they can't be high sound quality drivers, cause quality drivers shall by definition not filter anything out, but reproduce the signal truthfully as it is!
> If I on purpose wanted to replay a clipped signal just to hear what it sounds like I sure wouldn't like my speakers to filter out the sound!


LOL, are you being serious right now? A voice coil is an inductor, it has inductance. It has NOTHING to do with whether or not a speaker is "HiFi", it's a fact of physics. Go look up the Le for your favorite high priced speakers. That is inductance of the coil. And there will be a number there for it. Or go look through the Klippel tests posted on this site. In reality, which is what we are concerned about, drivers inherently have inductance and other lowpass mechanisms that are virtually unavoidable. 



> Im not saying a clipped 10watt signal will instantly fry a 50watt speaker but if you are at the edge of your drivers thermal limit, a severly clipped signal can potentially damage speakers.


You are right, it can. But because of the higher average power over time, and not the shape of the waveform.



> So I guess we will just have to disagree on that one!


You may disagree. That doesn't make you right, though


----------



## squeak9798

Treesx4 said:


> From what I've read in my insomnia laced night.... Everyone has brought some very good points... But it seems the clipped signal = blown speakers is a good one.... Winwiz and others are correct.... the speaker is designed to follow the signal... It has to... If the signal is clipped ( I'm talking hard clipped, high output ) it will go from moving just like the signal,,,smoothly...sign wave, to pausing at the clipping point,,, square wave... now speakers are moving very fast,duh, and we are talking about mili seonds at best.... BUT think this way.... EXAMPLE...I know we all have used batteries to "pop" while checking speakers or for polarity.... would you hold a AA battery to that speaker??? Probably with no problem... Now 18v drill battery, or 12v car battery??? I wouldn't hold it for long... that's the problem with clipping is the more clipped the more the wave is cut flat.... the longer its held at THAT point... Would you hold a AC or DC motor ( eg... fan or starter) still and then turn it on while still keeping it still.... Nope it will burn it up.... Speakers, fans, starters, or transducers... are all the same electricity wise they want to MOVE smoothly.... If your system is well thought out x'd over at the right points.... YOU will be better off with more power than not enough evey time.... How many engines in a auto have been blown up with the go pedals on the floor vs on cruise control just hwy speeds??? Ive been in this hobby for 3 decades and we used to argue this crap in the instal bays or at shows, Im getting older and learning the forum stuff...because of that I usually don't reply on forums... so its hard for me to get my points across and I'm not trying to be an ass... But its these debates that makes us all better.... I'm very happy I found DIY MOBLE audio.....


Not how it happens. Not going to argue every point again because it's all already here on the forum, read this thread: http://www.diymobileaudio.com/forum/general-car-audio-discussion/87065-underpowering-sub-4.html

Pay attention to posts by Lycan and MarkZ. It even has graphs of how the lowpass nature of the loudspeaker will affect the shape of the waveform and hence the motion of the coil. 

Power, not waveform, is the killer.


----------



## cajunner

I think waveform is a factor.

The reason I say this, is because square waves, or clipping, transmits power to a specific portion of the voice coil, that is at the ends of it's stroke, and the energy being inductively coupled to the ferrous plate/pole, is at the same places.

on an overhung coil, the coil's top and bottom are getting more heat from induction-related dissipation of energy, when driven by square waves because the coil is remaining in that static position for longer periods.

think of it like a pot on a stove, with 2 burners.

moving a pot back and forth rapidly between the burners, but keeping the pot on the burners for a longer periodic interval, means you will get more heat transfer into the pot, all things considered.

Now, I am aware that moving the pot back and forth causes dissipative heat loss from convection, and the movement aids in pumping air through the gap, but the inductive transfer of energy is that which is counter-intuitive, as it's not radiation, convection, normal conduction through contact, it's magnetic in principle and not as easily understood.


so, clipping serves to heat the coil unevenly is my premise, because of inductive energy transfer to the coil.

a sine wave distributes the inductive energy across the coil's winding in an even process, and the coil can withstand a greater amount of power over time in comparison.


that's the missing link in this debate, I think.

that induction is responsible, and clipping kills speakers more easily due to the uneven transfer of electrical power, even if power over time is the normally accepted conventional explanation.


----------



## squeak9798

Everything I have ever seen of any scientific merit other than simple "intuition" notions disagrees with that viewpoint. The coil is never really at a "static" position. Read the other thread. Think about how the inductance/etc is going to affect the shape of the wave. Think about the fact the coil is still moving X times per second....the amount of difference in cooling is minuscule at best.

Or, go test it yourself. As I said, 95Honda tested exactly your theory and the test showed no difference in failure times due to waveform under normalized power conditions. If the waveform was to blame, for the reason you mentioned, the squarewave would have lead to earlier failure times than the sine wave. But it didn't. Why is that? Think about it.


----------



## cajunner

squeak9798 said:


> Everything I have ever seen of any scientific merit other than simple "intuition" notions disagrees with that viewpoint. The coil is never really at a "static" position. Read the other thread. Think about how the inductance/etc is going to affect the shape of the wave. Think about the fact the coil is still moving X times per second....the amount of difference in cooling is minuscule at best.
> 
> Or, go test it yourself. As I said, 95Honda tested exactly your theory and the test showed no difference in failure times due to waveform under normalized power conditions. If the waveform was to blame, for the reason you mentioned, the squarewave would have lead to earlier failure times than the sine wave. But it didn't. Why is that? Think about it.



normalized power conditions.

when an amp is clipping, it's not just making square waves.

when the toroid saturates, it pushes a lot of nasty high frequency energy through the transistors, along with your solid square wave content.

this high frequency energy is not accounted for, when you've "normalized" the circuit for non-clipping operation.

that's one thing.

the other thing, is that even if the coil "appears" to not be static, you don't have the quickness of eye, to determine if the coil is or isn't being static, or held over longer periods at that periodic interval of a square wave.

the straight across power delivery into the coil during the square wave, means over time there is uneven power distribution, that has to be perfectly clear...

you have to look past the acoustic time interval, and look at the electrical time interval.

overshoot and ringing THD should, actually help, if your position is that the coil is never in a static condition.

I believe that the coil may dwell longer in that static condition than what's intuitive, because you're getting a pseudo-sine wave output registering on a microphone, when the electrical input to the coil is actually a square wave.

Any little bit of dwell time, is sufficient to support my hypothesis.

That's all I need, proof that there's a change in power over time, to demonstrate that clipping will affect the coil in an adverse way. Add to that the dirty power from a saturated transformer, and you have a recipe that exceeds a basic square wave input using "normalized" power input.


----------



## BuickGN

If the coil is truly pausing at each end of stroke, to produce the same number of cycles per second it's going to have to move quicker to afford the time to pause at the ends. I have no idea if the coil really pauses and I'm not going to guess. But if it does, this might support those that say clipping can mechanically damage a sub. Then again I can't imagine this being any harder mechanically or maybe even thermally on a sealed sub than a ported sub that has higher stress and nearly stops moving near tuning frequency with a clean signal. 

I hope with my subs being in plain sight in the cabin I would hear some kind of distortion before it's too late. I don't know why but my amp has never shut down from long deep bass notes, it's the quick punch that has made them shut down for a few seconds. 

This is probably a dumb question and not related but does clipping affect class D amps with feedback differently, will they go into protect when or before clipping occurs?


----------



## cajunner

if I had to guess, I'd say that the dynamic pulse initiated by the quick punch, is going to put a condition on the circuit that if continued, would cause the amp to break.

so the person who engineered the protection circuit, programmed the response to that end, and the long bass notes do not engage the peak limiter, and so do not require the amp to shut down. In that case, the temperature protection circuit will have to suffice, because the amp isn't in a fail mode at any point until it reaches critical temps.

I know it seems like there's a mountain of evidence and people saying that clipping doesn't harm speakers, but I have personal observations and experience, backed up with the conjecture.

And if you go back to the old reviews in magazines, you see some magazines doing impulse testing of tweeters using over a thousand watts!

Clean, unsaturated, unclipped watts.

now, that's not "power over time" and something else, but it's also an indicator that if speakers fail when amps clip, it's not "power" itself that is the problem. It's something else.


----------



## Hanatsu

It's common knowledge that a speaker can handle very high power input during short bursts, talking milliseconds here. Dynaudio even rates this in their specs.

Power is all that matters, if a speaker handles 100Wrms it shall handle 100Wrms of power CONTINUOUS. This is nothing but a thermal power rating and nothing about the waveform it's fed with. Clipped signals contain MORE POWER than a sine wave, a pure square wave contain 1,414x the power of a pure sinewave, i.e twice the voltage. U²/R=Power, this means that 1,414 times the voltage is twice the power...

ALSO, a severely clipped signal WILL CAUSE less cooling of the VC which means any speaker is likely to fail quicker if OVERPOWERED with a clipped signal than a sine wave.

Why Too Little Power will NOT blow Your Speakers


----------



## cajunner

power ratings are variable, each manufacturer has a standard and then there's CEA 2006, I guess.

but speaker power ratings are still unreliable, Pioneer and JBL and JL all severely under-rate their speaker's ability to absorb short term, continuous power but then, they also add a dynamic rating that is closer to the signal that a musical input provides.

and I guess my inductor thing isn't going over too well, haha...

oh well.


----------



## Hanatsu

cajunner said:


> but speaker power ratings are still unreliable, Pioneer and JBL and JL all severely under-rate their speaker's ability to absorb short term, continuous power but then, they also add a dynamic rating that is closer to the signal that a musical input provides.


Yeah... Manufacturers specs are severely off sometimes. I remember measuring a TangBand w3-871 8ohm speaker which was specced at 15Wrms continuous. Had it playing a 1kHz tone to calibrate SPL, when I fed it about 2,9-3 volts the VC started to give off that nasty white smoke. 3*3/8 ~ 1,1W. This was like 30sec after I applied the signal. Just like T/S parameters, I treat those specs as BS most of the time. Some manufacturers like Scan Speak, Seas and a few others are pretty reliable though.


----------



## cajunner

Hanatsu said:


> Yeah... Manufacturers specs are severely off sometimes. I remember measuring a TangBand w3-871 8ohm speaker which was specced at 15Wrms continuous. Had it playing a 1kHz tone to calibrate SPL, when I fed it about 2,9-3 volts the VC started to give off that nasty white smoke. 3*3/8 ~ 1,1W. This was like 30sec after I applied the signal. Just like T/S parameters, I treat those specs as BS most of the time. Some manufacturers like Scan Speak, Seas and a few others are pretty reliable though.


HAHA..


so, those Scandinavian companies pass muster, heh..



but that poor Taiwanese buildhouse can't make weight, hahaha...


----------



## BuickGN

It seems like most of the higher end speakers end up pretty close to TS specs and xmax while many of the lesser speakers outright lie about most parameters, especially xmax. That's not always the case obviously but more often than not. 

I like the Dyn 10ms power rating. I think of this as the amount of power it takes to open a voice coil nearly instantly. I was going to say that I'm feeding my midbass a lot more power than they're rated for but with 300w available for each one I'm obviously below the short term power handling and I don't imagine I'm past the 180w long term by much if at all a d of course that's only at full tilt. I have had the bridged 600/4 shut off a few times on loud passages so assuming a good installation I dont know if that means I've tried to exceed the 600w continuous rating or if there's even more power getting to the midbass. Regardless I'll probably add more power in the future to the midbass and mids. Maybe a 750/1 on each midbass and bridge a 600/4 on the mids.


----------



## squeak9798

cajunner said:


> normalized power conditions.
> 
> when an amp is clipping, it's not just making square waves.
> 
> when the toroid saturates, it pushes a lot of nasty high frequency energy through the transistors, along with your solid square wave content.
> 
> this high frequency energy is not accounted for, when you've "normalized" the circuit for non-clipping operation.
> 
> that's one thing.


And that would apply additional POWER to the coil. That is not what you were discussing. You were talking about waveform. 



> the other thing, is that even if the coil "appears" to not be static, you don't have the quickness of eye, to determine if the coil is or isn't being static, or held over longer periods at that periodic interval of a square wave.
> 
> the straight across power delivery into the coil during the square wave, means over time there is uneven power distribution, that has to be perfectly clear...
> 
> you have to look past the acoustic time interval, and look at the electrical time interval.
> 
> overshoot and ringing THD should, actually help, if your position is that the coil is never in a static condition.
> 
> I believe that the coil may dwell longer in that static condition than what's intuitive, because you're getting a pseudo-sine wave output registering on a microphone, when the electrical input to the coil is actually a square wave.


And if this "dwell time" was enough to significantly affect cooling, then the squarewave would have caused the driver to fail sooner. It did not. Hypothesis disproven. Power, not waveform, is the culprit.


----------



## cajunner

squeak9798 said:


> And that would apply additional POWER to the coil. That is not what you were discussing. You were talking about waveform.
> 
> 
> 
> And if this "dwell time" was enough to significantly affect cooling, then the squarewave would have caused the driver to fail sooner. It did not. Hypothesis disproven. Power, not waveform, is the culprit.


actually I was talking about clipping, and waveform was a result of that.

the square wave may not be damaging by itself, (although I can remember a while back in a magazine article long ago and far away, one testing lab stating this exact point, square waves are damaging in and of themselves) but when it's in the context of clipping, the combination of out-of-band energy in concert with the square wave's deleterious effects, is enough to create dead speaker syndrome.

Hypothesis still alive, and kicking...!


----------



## WinWiz

cajunner said:


> check this out:
> 
> I have recently been inducted into the queue of induction plate cooking.
> 
> (hah!)
> 
> so, let's remember that power in, doesn't equal acoustic power out.
> 
> and that a voice coil is an inductor that you put electricity into.
> 
> the efficiency of that coil to transfer the electrical energy to acoustic energy is somewhat less than 5% for even some of the best drivers.
> 
> that means that 95% of that energy is dissipated as heat.
> 
> now, let's enter the induction cooker theory.
> 
> that coil, is going to be releasing 95% of it's energy in some way, through heat.
> 
> I propose, that when a speaker is "stuck" in the clipped waveform, it's spending a lot more time in that one area at the top and the bottom of the waveform, and that's where the heat is being inductively coupled to the pole piece and top plate gap.
> 
> the coil is acting like an induction stove's coil, it's heating up the surrounding ferrous metal parts that are activated by the induction energy transfer.
> 
> so, when it's moving normally the coil distributes the inductive energy more or less, evenly.
> 
> when it's clipping, it's distributing the energy at the top and bottom of the coil's travel, over a longer time period, which leads to those places getting more energy than before, without clipping.
> 
> 
> so, as the surrounding structures heat up, this also raises the temperature of the coil itself, causing the glues to soften, the former to warp, the copper itself to expand and delaminate from the former.
> 
> all signs of heat damage, that is the result of clipping energy being distributed unevenly by the induction process at the top and bottom of the waveform.
> 
> how's that for blow your mind?
> 
> 
> haha.
> 
> 
> that 95% of energy, in watts going someplace, means that it's no joke that a motor needs to dissipate heat, and motors that can't shed heat will fail.
> 
> 
> maybe someone can disprove this hypothesis, but I think we're on a track now...


Wise words!
I believe this is the best and most likely explanation of why clipping hurts. 
Cajunner I think your def. on the right track her!

Regarding manf. specs:
Some manf. simply dont public any specs, some lie and overrate their products and some underate. Personally I prefer to deal with the underrating manufacturers!


----------



## Treesx4

Bottom line... why would you want to send a clipped signal into a speaker??? I do agree that you should set a system and get every drop of power... I do agree that clipping won't lead to global warming... its not that big of deal, to most of us that really understand what we are doing.... BUT to the below average person in car audio that isn't educated that turns it up all the way, just cause he can.... Will torch more speaker due to lower power higher distortion..... So is it the distortion or clipped brain cells... I personaly have NEVER blown a speaker or even a fuse in one of my systems....


----------



## WinWiz

Well honestly I do not understand the "max it until it clips or overheat" mentality that seems to rule here on diymobile...
Personally I prefer a lot of headroom, what ever happened to the old "never above 12 a clock" (50%) volume on the amps mentality??
The power specs of amps makes it quite clear that amps have more distortion when they are loaded down to maximize power output, so for SQ I think its better to get a "overpowered" amp instead of "trying to utilize 100%" of a smaller amp.
Am I missing something here??


----------



## Golden Ear

WinWiz said:


> Well honestly I do not understand the "max it until it clips or overheat" mentality that seems to rule here on diymobile...
> Personally I prefer a lot of headroom, what ever happened to the old "never above 12 a clock" (50%) volume on the amps mentality??
> The power specs of amps makes it quite clear that amps have more distortion when they are loaded down to maximize power output, so for SQ I think its better to get a "overpowered" amp instead of "trying to utilize 100%" of a smaller amp.
> Am I missing something here??


To me it seems like more people agree with you than disagree. Just read some of the build logs and you'll see people putting 200+ watts to tweeters. I, on the other hand, would rather save some money and only spend on an amp that puts out the power that I'm going to use rather than power that will forever sit there untapped.


----------



## cajunner

WinWiz said:


> Well honestly I do not understand the "max it until it clips or overheat" mentality that seems to rule here on diymobile...
> Personally I prefer a lot of headroom, what ever happened to the old "never above 12 a clock" (50%) volume on the amps mentality??
> The power specs of amps makes it quite clear that amps have more distortion when they are loaded down to maximize power output, so for SQ I think its better to get a "overpowered" amp instead of "trying to utilize 100%" of a smaller amp.
> Am I missing something here??


it's because there is no old "never above 12 o'clock" analogous to gain, as each amplifier has a different ratio of min to max gain.

one amp could adjust from 250mV to 3V, and another amp could adjust from 100mV to 1V, and another amp could go from 2V to 16V.

in home audio, there are common standards that cap the line level voltages and input/output impedances, to ensure most consumer product is able to work with each other.

in car audio, the gain at 12 o'clock could be 500mV on one amp, and 2V on another. That's a huge swing.

and on source units, the same problem exists!


so it's important to remember that a system that is maximized for gain, will have the source unit push as much undistorted voltage to the next component in line to meet it's S/N ratio specs.

an issue of late, is overdriving the inputs to digital processing units. Another wrinkle the home audio industry has seemingly ironed out, because of their adoption of standards.


If a deck can put 3V undistorted into an amp designed to max out at 2V, (like most old school amps) then you will certainly be able to drive that amp into clipping on occasion. Drive a DSP with that 3V, one that only takes 2V, and you can cause some serious issues with your system.

Anyways, I remember my old Technics receiver from 1982 or so having the ability to only use 50% of it's volume knob's range, (tone controls set to flat) and when I connected an equalizer to it with the smiley face curves, it would go about 4 detents to listening level, and 6 detents to distorted output, on a 32 click knob?


----------



## WinWiz

Regarding S/N and amp gains...
I have been thinking about adjusting my gains.
Before I reconfigured the amps my system would play "very loud" when the 80prs was only at 30 so I never had any need or desire to turn it up more than about 35 or so...
After I reconfigured the amps I need to turn the volume a little higher to like max 40 to match the previous volume at 35.
But the 80-prs goes to like 62 (or is it only 52?) so I realise i'm not getting anywhere near 5v on the rca outputs does this hurt the SQ of my system?
I don't wanna turn the dial 4 turns just to reach normal volume if I don't have to. normal volume at 25 would suit me best.

Do you think I would improve the sound if I lower my gains to get higher voltage from the RCAs?


----------



## Hanatsu

Gains should be set correctly. There's no golden "only use half of the output" rule. You'll have headroom by having enough power output from the amplifier at the level you like listening at. Reducing gains to the point where's there no clipping at all will only reduce the output capability of the system, if you don't have enough power and don't wanna allow any clipping the system will most likely not be especially loud. No music is recorded at 0dBFS anyway so it's simply redundant to be so conservatory with the gain knob. Use a -10dB sine tone together with a scope or use your ears.


----------



## Hanatsu

WinWiz said:


> Regarding S/N and amp gains...
> I have been thinking about adjusting my gains.
> Before I reconfigured the amps my system would play "very loud" when the 80prs was only at 30 so I never had any need or desire to turn it up more than about 35 or so...
> After I reconfigured the amps I need to turn the volume a little higher to like max 40 to match the previous volume at 35.
> But the 80-prs goes to like 62 (or is it only 52?) so I realise i'm not getting anywhere near 5v on the rca outputs does this hurt the SQ of my system?
> I don't wanna turn the dial 4 turns just to reach normal volume if I don't have to. normal volume at 25 would suit me best.
> 
> Do you think I would improve the sound if I lower my gains to get higher voltage from the RCAs?


I tend to lower the gains on my tweeter/midranges amp so my headunit outputs higher voltage to the DSP. I only do so because I have enough power AND because of the improved SNR (outside noise).

62 is max at my p99rs. Very loud usually lies around 50-55 in my setup, whilst normal listening volume usually lies around 40-45. I don't think the volume knob/preout voltage got "linear" increments either. It feels like it boosts the signal more around 58-62. Unless you running sine tones at 0dBFS and have the volume knob at maximum, most headunits outputs much less voltage than the specced one on a average/continuous basis.


----------



## WinWiz

Golden Ear said:


> To me it seems like more people agree with you than disagree. Just read some of the build logs and you'll see people putting 200+ watts to tweeters. I, on the other hand, would rather save some money and only spend on an amp that puts out the power that I'm going to use rather than power that will forever sit there untapped.


I guess thats the difference between SQ and SPL...
But your nick is golden ear? If you use all the power from you amp it will have lots of distortion, how can someone with a golden ear stand that?
I would rather listen at half the volume with near zero distortion and no power compression etc. than have my hearing damaged from the high spl and distortion from an amp at full power...
And these days you can get great amps dirt cheap, just find the old proven sq amps used!
I have just sold a Ground Zero titanium 1200w amp...
[email protected] 10% distortion!! It may be 1200w and 1 ohm stable but the distortion is 10%!! No thank you not for me!
@1000w the distortion is "only" 1%! Would you also try to max your amp if you knew for sure it behaved the same way?
And how different do your amp behave at full power??

Maybe I'm just old...


----------



## WinWiz

Hanatsu said:


> Gains should be set correctly. There's no golden "only use half of the output" rule. You'll have headroom by having enough power output from the amplifier at the level you like listening at. Reducing gains to the point where's there no clipping at all will only reduce the output capability of the system, if you don't have enough power and don't wanna allow any clipping the system will most likely not be especially loud. No music is recorded at 0dBFS anyway so it's simply redundant to be so conservatory with the gain knob. Use a -10dB sine tone together with a scope or use your ears.


The part about: "No music is recorded at 0dBFS anyway" is becoming outdated. Try google the loudness war 

I really don't care horseshit if my system clips above 45 because I nor anyone I know will never play it that loud. So if i'm not losing real world SQ (volume corrected blind test anyone?) I will keep my gains so that I do not have to turn the knob 2-3 turns just for normal volume.


----------



## WinWiz

Hanatsu said:


> I tend to lower the gains on my tweeter/midranges amp so my headunit outputs higher voltage to the DSP. I only do so because I have enough power AND because of the improved SNR (outside noise).
> 
> 62 is max at my p99rs. Very loud usually lies around 50-55 in my setup, whilst normal listening volume usually lies around 40-45. I don't think the volume knob/preout voltage got "linear" increments either. It feels like it boosts the signal more around 58-62. Unless you running sine tones at 0dBFS and have the volume knob at maximum, most headunits outputs much less voltage than the specced one on a average/continuous basis.


I think a linear volume knob would be awkward to operate...

But can you actually hear any difference in sq due to the higher SNR at the lower gain setting? Isnt SNR so high on modern hifi that its way below what a human can actually hear anyway??


----------



## Hanatsu

WinWiz said:


> I think a linear volume knob would be awkward to operate...
> 
> But can you actually hear any difference in sq due to the higher SNR at the lower gain setting? Isnt SNR so high on modern hifi that its way below what a human can actually hear anyway??


You misinterpreted my entire quote 

Not linear knob, I know most of them is log based. I meant the increments over a certain range worked logarithmically but the top end of scale somehow was boosted above the logarithmic steps. 

By SNR here, I was referring to RFI and EMI. The ratio between the "external" noise and the signal strength in the cable (voltage) would determine the SNR. A lower voltage in the cable would mean that the amp would amplify any noise present as well much louder since the ratio would be lower.

...and yes. It can be very audible.


----------



## Hanatsu

WinWiz said:


> The part about: "No music is recorded at 0dBFS anyway" is becoming outdated. Try google the loudness war
> 
> I really don't care horseshit if my system clips above 45 because I nor anyone I know will never play it that loud. So if i'm not losing real world SQ (volume corrected blind test anyone?) I will keep my gains so that I do not have to turn the knob 2-3 turns just for normal volume.


I'm very aware of the loudness wars. No "competently recorded" music reaches 0dBFS anyway, if it does someone has really screwed up in the recording process and it will sound like crap anyway.

We're not talking about "gaining SQ" here. We're talking about reducing the possibility of noise in our systems. If there's noise present (even low amounts) in the signal cables to the amp, the amplifier will amplify the noise in a GREATER AMOUNT. Regarding hearing differences, I'd take on that challenge any day (if there's even a small amount of noise, it will be audible as soon you increase the volume. Especially on quiet portions of some songs)


----------



## Hanatsu

WinWiz said:


> I will keep my gains so that I do not have to turn the knob 2-3 turns just for normal volume.


It's really not that bad...


----------



## WinWiz

With no dedicated pause or mute button on the 80prs (havent integrated the remote in my steering wheel yet)I already find it a little irritating when I have to turn it all the way down from about 30, so I think I would find about 50 very annoying.

Before I moved my tweeters to the onboard amp I could sometimes hear a faint noise when listening at night in total silence with my ear very near the tweeter on certain mp3 files... But after i'm using the internal amp I can't hear ANY noise at all except when my phone rings. Will lower gains/higher voltage on rca make the noise from my phone go away?


----------



## WinWiz

I think the gains on my old fosgate punch 150 is still at the factory setting, 32dBV !
According to the manual this is correct for most 500 millivolt sources, so I guess my 80-PRS is able to drive it into clipping even at a very low volume setting...
I think I will try the min. gain setting, if it is better I can live with having to turn the volume dial a little more


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## Golden Ear

WinWiz said:


> I guess thats the difference between SQ and SPL...
> But your nick is golden ear? If you use all the power from you amp it will have lots of distortion, how can someone with a golden ear stand that?
> I would rather listen at half the volume with near zero distortion and no power compression etc. than have my hearing damaged from the high spl and distortion from an amp at full power...
> And these days you can get great amps dirt cheap, just find the old proven sq amps used!
> I have just sold a Ground Zero titanium 1200w amp...
> [email protected] 10% distortion!! It may be 1200w and 1 ohm stable but the distortion is 10%!! No thank you not for me!
> @1000w the distortion is "only" 1%! Would you also try to max your amp if you knew for sure it behaved the same way?
> And how different do your amp behave at full power??
> 
> Maybe I'm just old...


I didn't say I want to use an amp to the point of distortion. I said that I want to use all of an amps usable power. That means power available before distortion. If that means 130 watts to my tweeters (which is what I currently have) then so be it. I just don't see how putting 400 watts to a tweeter is going to make it sound any better or play any louder if the tweeter is rated for 50 watts. I'm sure there is something I'm missing because I'm no electrical engineer. 

10% distortion would be terrible. My JL HD amps are rated at .03% distortion. From what I've learned the human ear cannot discern 1% distortion or less. Once again I could be wrong.


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## cajunner

actually, 10% distortion is not terrible, depending on the frequency and the duration of time when distortion occurs.

10% distortion is certainly audible, but if it's only at the very top of waveform peaks, or I should say signal peaks, then the duration is not very long at all and people will have a very hard time hearing it.

This is light clipping, when the majority of the sound is powered cleanly and an amp only momentarily clips. It's also when you are finally getting at the threshold of too much power, or not enough money.

I believe that speakers that can handle music program peaks of several hundred watts, can also absorb the occasional square wave signal's dirty power, which is why it's perfectly okay to run your amp into an occasionally clipping level as far as that goes.

the main issue is when you set a volume level that has 30% or more distortion, which is distortion over much longer duration and clipping becomes a negative.

the setting of the volume is what is killing the speakers, because if you can hear the distortion it's not "just barely clipping" anymore. That's where people tend to get in trouble, they listen for distortion, and if it's not too bad or disrupting their enjoyment of the song, they think it's okay for the speakers, but that's about 20% more distortion than what is acceptable.


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## Hanatsu

"Distortion" is such a wide concept to begin with. EVERYTHING that deviates from the source material would be 'distortion'.

Clipping creates a great deal of non-linear distortion. Depending on the symmetry of the clipped waveform, it consist of mainly even or odd order non-linear distortion. Odd order distortion is widely considered to be more offensive than even order. Unfortunately, most solid state amps will mainly create odd order HD/IMD when it clips. The audibility of this non-linear distortion is a complicated matter, steady state distortion is more audible than transient distortion for example. It's also frequency dependent (might even be level dependent according to Gedlee), generally the non-linear distortion might be audible from 1-10% (completely arbitrary numbers here) depending on condition.


----------



## WinWiz

Golden Ear said:


> I didn't say I want to use an amp to the point of distortion. I said that I want to use all of an amps usable power. That means power available before distortion. If that means 130 watts to my tweeters (which is what I currently have) then so be it. I just don't see how putting 400 watts to a tweeter is going to make it sound any better or play any louder if the tweeter is rated for 50 watts. I'm sure there is something I'm missing because I'm no electrical engineer.
> 
> 10% distortion would be terrible. My JL HD amps are rated at .03% distortion. From what I've learned the human ear cannot discern 1% distortion or less. Once again I could be wrong.


130w is a lot for tweeter, take care of your ears man 
Can the rest of your system keep up with the tweeters output at 130w ?

I drive with my dog in the car 99,5% of the time so I don't play very loud.
My ears are already a little damaged at high freq's because I worked for years selling ice cream, so I don't wanna damage it any more.


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## I800C0LLECT

WinWiz...

I think what needs to be remembered is that music is dynamic. There's dips and peaks that may require a burst of energy in order to play. Due to differences in recordings, sometimes those peaks can be clipped with your current gain setting.

https://documentation.apple.com/en/finalcutpro/usermanual/index.html#chapter=52%26section=5%26tasks=true


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## Hanatsu

WinWiz said:


> 130w is a lot for tweeter, take care of your ears man
> Can the rest of your system keep up with the tweeters output at 130w ?
> 
> I drive with my dog in the car 99,5% of the time so I don't play very loud.
> My ears are already a little damaged at high freq's because I worked for years selling ice cream, so I don't wanna damage it any more.


I wasn't aware that selling ice cream was bad for your hearing. Lots of screaming kids eh? xD

Sent from my Samsung Galaxy 3 via Tapatalk.


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## Golden Ear

WinWiz said:


> 130w is a lot for tweeter, take care of your ears man
> Can the rest of your system keep up with the tweeters output at 130w ?
> 
> I drive with my dog in the car 99,5% of the time so I don't play very loud.
> My ears are already a little damaged at high freq's because I worked for years selling ice cream, so I don't wanna damage it any more.


The rest of the system keeps up perfectly because I use a dsp to set the levels of all the speakers. On the Pioneer hu in that car I rarely turn it up past 15 and that's when I'm alone. It's the family car so usually it's closer to 10-12 on the volume.


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## WinWiz

But someone here on DIY told me that to maximize S/N I should adjust my gains so that my headunit is almost at max (about 60) when I play really loud. But you say your system plays loud with the volume at only 15? The Voltage on your rcas must be really low.

Selling ice cream is bad for the ears because you have to constantly ring a very noisy bell!


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## cajunner

WinWiz said:


> But someone here on DIY told me that to maximize S/N I should adjust my gains so that my headunit is almost at max (about 60) when I play really loud. But you say your system plays loud with the volume at only 15? The Voltage on your rcas must be really low.
> 
> Selling ice cream is bad for the ears because you have to constantly ring a very noisy bell!


maximizing S/N ratios, is really only important if you're getting equipment noise, or hiss from the install.

if you've got quiet equipment, you can have your amp maxed out at 250mV, which on a 5V deck, might be 30% of the way to the stops, and not hear noise.

that's the key, is if you encounter noise, you have enough available voltage to set the floor above it. You may never need more than 250mV of voltage, if your amp can max out at that level.

In the old days, 250mV was an actual max level on some equipment, Alpine wasn't much higher at 500mV. That means that their tape decks used to put out 500mV on their pre-amp outputs, that's it! Amps used to adjust from 100mV upwards to 1V, that was a common range on the gain controls.


and they didn't all have noise!


So when you feel like you need to drive your S/N into the ground by pushing 5V of line-level into the amps, it's possibly not necessary. But if you have it, some say go ahead and use it.

Myself, I choose convenience before noise floor concerns, but if I had hiss, I'd probably think differently about it.


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## WinWiz

Thanks for the info!
I was getting the feeling I was losing sq but not running my headunit rca near 5V, But I really like to have my max usable volume around 30 instead instead of near 60. I was also wondering if the high s/n was required in a somewhat noisy car environment...
So your info has convinced me that since I can't hear any noise at high volume when the music is silent, even with my ear against the tweeter, windows up and engine off I don't need the higher voltage from my headunit.


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## WinWiz

I800C0LLECT said:


> WinWiz...
> 
> I think what needs to be remembered is that music is dynamic. There's dips and peaks that may require a burst of energy in order to play. Due to differences in recordings, sometimes those peaks can be clipped with your current gain setting.
> 
> https://documentation.apple.com/en/finalcutpro/usermanual/index.html#chapter=52%26section=5%26tasks=true


I am aware that music is dynamic. I like pink floyd and some of their recordings are very dynamic.
I also like trente møller, the track chameleon from the last resort is a challenge to almost all amps and speakers. Seems to use a lot of power even at low volume. I once had a fan cooled class A technics amp and the chameleon track would make the fan spin like nothing else


----------



## WinWiz

Golden Ear said:


> The rest of the system keeps up perfectly because I use a dsp to set the levels of all the speakers. On the Pioneer hu in that car I rarely turn it up past 15 and that's when I'm alone. It's the family car so usually it's closer to 10-12 on the volume.


I dont think you understand my question about the rest of your system being able to keep up...
What I meant was that the sound pressure from a tweeter feed a 130w signal, I assume we are not talking 130 walmart peak watt but true sustained watts, would require insane mid and bass power. If your dsp lower your tweets to match the output of your mids you are actually wasting unused power by feeding your highs 130w !!
Personally my tweets gets about 2x14W, my mids gets about 2x80w and my sub about 2x150 but I still has to lower the tweets to match the rest of my system.
So basicly if you don't have like 600-800w on your mids, I don't think you can use 130w tweeting power to anything but brag.
But of course this gives your tweeters a very big overhead


----------



## Mapletech

First up - I'm firmly in the 'less power will blow speakers' camp, partly because of all the technical reasons here - the net RMS power to the speaker being basically full rail voltage in the case of extreme clipping, the start-stop motion being implied on the speaker cone (momentum notwithstanding).
But mostly it's because of simple human nature - we're going to want it 'xx' loud, and will turn it up until we perceive loudness - either in the form of some distortion as others have said (an underpowered system), or until there's sufficient real SPL that we call it loud enough (a well-powered system).

From my real-world experience: In pro audio we usually put the same amplifiers for the entire set of drivers, with possible exception of subs. Take your typical line-array that you'll see at any amphitheatre or arena. Each box I'm most familiar with has 2x 15" drivers (rated about 600 watts each), 4x 8" drivers (around 150 each), and 2x compression horns rated 75 watts each. Remember these values are real power per driver - most tweeters that we're all buying for car audio are rated something like 90W @ 2.5kHz 12db/oct. I'm not going to do the math, but given the power/spectrum above 2/5kHz, that tweeter is probably getting 10W or less of real power. Anyhow - back on track, for a box like this we would want an amp with minimum 1500W at 4 ohms, preferably 2000.
Why? Transients! As long as the mix is clean, and even with modern techno, etc., the bulk of the power is still around 15-30% of the peaks.
But here's the reason why we also want that much power AVAILABLE to the horns (tweets) - Slew Rate, and an 'easy' load. Slew rate is the rate at which an amp can get from 0V to full output power. So, a 10 watt amp, powering a 4 ohm load, needs only be able to ramp up 6.3 volts in .1ms to produce a 10kHz transient. But, a 1000 watt amp needs to be able to ramp up to 63 volts in the same time. The upward curve of that sine wave is steeper - ie. the higher powered amplifier is essentially capable of higher frequency response at lower output levels.
When properly tech'ed, systems will allow the occasional blink of a clip light, but nothing prolonged, and I have never seen a driver powered as such get blown. This includes sending near-clip levels to those horns (transients!). If nothing else, consider that a pro-touring company just can't have drivers getting blown on a regular basis - the system has to work every night, flawlessly, and this is how they do it.
The other reason for such power is something I haven't seen yet on the speaker-wire discussions here (and please don't berate me if so - I'm still getting around)...damping factor. This is the ability of the amplifier to induce and fight momentum. Basically, at a given voltage, given the impedance curves, you would expect there to be a given current as based on ohms law. But since the coil is moving, there is always 'back voltage' (there are those who can go into the engineering of this). Bottom line is that the output stage /transistors/mosfets/whatever in a better amp can push and/or absorb more of that current in order to better move the driver exactly the way it should be. Bigger amp = more capability to do that.
All that said, it does come down to how the rig is tech'ed, and whether the person driving the rig is using the power intelligently, or pushing it into ear-bleed. 
I have seen a few 18's lit on fire because of excessive clipping on rigs that I was not responsible for!
Last nut not least - several people have referred to Post #37, referring to compression being equal to clipping. Wrong, except for in the first few milliseconds or less, or with absolutely stupid settings. Compressors work like very fast monkeys with little volume controls in their hands. When they see a wave come through that exceeds the threshold (not clip, just a predetermined threshold), they turn down the volume. So yes - a tiny bit of 'over' signal may get through (remember I said we let rigs run with the occasional blink). The following bunch of waves will then have had their volume reduced below the threshold. When the monkey no longer sees full-scale waves for a certain amount of time (the release setting), he will start to turn the volume back up to nominal. Getting these settings right is one of the arts of audio. But - if someone sets stupid short attack and decay times, then said monkey will be working fast enough to trim each and every wave, thus making it into a squared off wave. Ok it's a cheesy analogy but factually correct.


----------



## deltasaurus

Mapletech, I have some pro audio experience, sound crew for a couole of popular 80's metal bands, and agree with how PA's should be setup and run. Doing that, I also have never cooked a cabinet. I wish that 12v audio would more easily allow these kinds of " over powered" setups. The main problem that I run into is the actual amperage requirements are tough to meet in the vehicle. I know the SPL crowd can get into some very complex charging systems, but they are just not practical in SQ cars. Jusy MHO though. This thread is a good one and I like the debate. For me this is year 30 around audio and I am still learning something new every day.


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## Mapletech

Fair point about the amperage, and as is almost always true, the real solution lies somewhere in the middle. I wouldn't expect that any sane person would set up their rig with all 1200 watt or whatever amps.

To literally put my money where my mouth is, I've just finished purchasing, and am about to start my own build, which is based on a JL 600/6, so 100W will be going to each of - Rear Coax, Front 6.5's, and yes - Front Tweets.


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## deltasaurus

I realize whatvI posted may have come off a bit dickish and don't want it to. I really agree with what you have said and try to put that to practice as closely as possible in my home and mobile audio systems. Have to to hear after all the heavy listening done in my younger years.


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## aerfgt79

Great posting,thanks for these infos !!!


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## rxonmymind

Ok dumb question. Now that I have my JL Audio amp installed, what happens to the power that is *IN* the head unit? Where does it _go_ once you hook up an aftermarket amp? You know the 22Wx4 that's built into the HU. Does it supplement the after market power amp? Get turned off/bypassed?


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## turbo5upra

rxonmymind said:


> Ok dumb question. Now that I have my JL Audio amp installed, what happens to the power that is *IN* the head unit? Where does it _go_ once you hook up an aftermarket amp? You know the 22Wx4 that's built into the HU. Does it supplement the after market power amp? Get turned off/bypassed?


If you've added an amp and no longer using the amp inside the source then it's just less the power supply in the source has to work. That power is turned into a cleaner signal for your jl amp.


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## rxonmymind

turbo5upra said:


> If you've added an amp and no longer using the amp inside the source then it's just less the power supply in the source has to work. That power is turned into a cleaner signal for your jl amp.


Ah thanks. So it becomes dead weight then.


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## turbo5upra

rxonmymind said:


> Ah thanks. So it becomes dead weight then.


I wouldn't call it dead weight- it's more like tossing a few hundred pounds of weight in your car- car being the power supply in the headunit- the weight being the internal amp- then removing the weight. The car or power supply is less taxed and has an easier time which should in theory equat to better cleaner output to the rca's


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## Mapletech

rxonmymind said:


> Ok dumb question. Now that I have my JL Audio amp installed, what happens to the power that is *IN* the head unit? Where does it _go_ once you hook up an aftermarket amp? You know the 22Wx4 that's built into the HU. Does it supplement the after market power amp? Get turned off/bypassed?


What the others have said is essentially true, but I'll take another stab at explaining it, and the answer depends slightly on whether or not you have RCA outputs on your HU.

Within your HU, you have the 'source' section, which is the radio/CD player/MP3 decoders, etc., that produce a Line Level signal. You could think of all of these as separate components in a stereo system, each with RCA outputs. Selecting any one of them is akin to using a selector switch with a bunch of inputs and a single set of RCA outputs (and a volume control on that output).
The next stage in your HU is the amplifier stage - where that switched/volume controlled signal gets a voltage and current boost in order to drive the speakers. Remember that's all an amplifier really is - a voltage and current booster.

If you have and are using RCA outputs to the new amplifier, you're just replacing the internal amplifier with bigger, better amplification. But as for what you asked, the internal amplifier will continue to produce that higher voltage output, but it has NO LOAD since the speakers are disconnected. A good analogy to this is a portable generator. If it has no load, it still produces pretty much the same voltage, but it is delivering no current (therefore no Power - Power equals voltage times current). And just as the generator will still suck back 'some' gas to keep running, your internal amplifier will still use a miniscule amount of electrical power to run, but it's simply working with no load.

If you are running speaker level to the inputs of your new amps, the same generator analogy holds true. The input impedance of the new amps will be much higher than a speaker. This means that the new amps 'draw' much less current from the HU amplifier. Thus as others have said, your HU now has it easy - the amplifiers are still working, and delivering much the same voltage, but much less current, and will likely sound a bit better.


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## ajsmcs

After the long, in-depth debate on this subject which took place here (* http://www.diymobileaudio.com/forum/general-car-audio-discussion/172544-help-me-understand-power.html*) over the past few days, I feel like this sticky really needs to be edited. Despite most of it being true, the following section is patently WRONG, and needs to stop being repeated. Need clarification? See the thread I posted.

_"The lesson in all this is that you can never have too much power, and that big amplifiers rarely damage speakers. Little amplifiers driven into clipping burn out speakers. In the scheme of high fidelity, that last barrier to realism is having enough power and being able to approximate real-life loudness levels. The lesson in all this is that you can never have too much power, and that big amplifiers rarely damage speakers. Little amplifiers driven into clipping burn out speakers."_

Perhaps a better statement is that "Your sound _system_ can never be too powerful. Despite not intending to listen to music cranked to 11, you really need more power than you might think to actually imitate the dynamics of a live performance."

I say "system" to imply both powerful amplifiers ALONG WITH speakers that can actually handle that power.

Because you can never have too powerful of a sound _*system*_, but you can _*certainly*_ have too powerful of an amplifier.


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## gijoe

ajsmcs said:


> After the long, in-depth debate on this subject which took place here (* http://www.diymobileaudio.com/forum/general-car-audio-discussion/172544-help-me-understand-power.html*) over the past few days, I feel like this sticky really needs to be edited. Despite most of it being true, the following section is patently WRONG, and needs to stop being repeated. Need clarification? See the thread I posted.
> 
> _"The lesson in all this is that you can never have too much power, and that big amplifiers rarely damage speakers. Little amplifiers driven into clipping burn out speakers. In the scheme of high fidelity, that last barrier to realism is having enough power and being able to approximate real-life loudness levels. The lesson in all this is that you can never have too much power, and that big amplifiers rarely damage speakers. Little amplifiers driven into clipping burn out speakers."_
> 
> Perhaps a better statement is that "Your sound _system_ can never be too powerful. Despite not intending to listen to music cranked to 11, you really need more power than you might think to actually imitate the dynamics of a live performance."
> 
> I say "system" to imply both powerful amplifiers ALONG WITH speakers that can actually handle that power.
> 
> Because you can never have too powerful of a sound _*system*_, but you can _*certainly*_ have too powerful of an amplifier.


Even this is a bit inaccurate. While it's true that you can ruin speakers by giving them too much power, it's also very easy to limit an amplifiers output. Just because you have 1k watt of power available to each midbass, doesn't mean that the speaker gets that power. I would argue that you really can't have too powerful of an amplifier, because of how the gain structure works you can easily make the 1k watt amplifier provide an appropriate amount of power. 

So yes, you can overpower speakers, but you can also have incredibly powerful amplifiers that will never harm a speaker. This is why people say buy as much power as you can. Running a robust amp at a minimal level can increase the longevity of the equipment vs. running an amp at it's limit.


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## ajsmcs

Oh yeah, I totally agree on that. But I was more refuting the bit about "big amps rarely damage speakers." 

I suppose I could have worded it better.


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## Dewey

Just read this thru for the second time.
A ton of very good information.

the "turn up the gain until it clips" reminds me of a good 'ole engineer I used to work with, he was from Alabama:
"Tighten it down till it turns easy and then back off half a turn."

Are you out there Capt. Tibbits?????


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## Lushai

I agree that if gains are set correctly I don't understand why an amplifier would hurt any speaker that's setup appropriately. But I usually only see people turn the gain up too much when using smaller amps.
Doesn't a coil need to shed heat? If it's busy playing distortion or getting stressed out due to clipping, when will it get a chance to breathe? But I failed to mention my assumption of a poorly set gain.


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## oabeieo

This is all great accurate theory 
Too bad it’s hardly the case in a car with all the many effects the environment causes 

I would never dare count on some manufacturer to properly state the sensitivity of the exact drivers your getting either. Especially after 100hrs of play time 

That “only a little bit” going from “50w to 100w” is absolutely under rated. It adds a lot to the enjoyment of music up loud. We can bicker about it bit let’s face it hang. Above 150-200hz in a car, counting on all the drivers to behave perfectly minimum phase with themselves and each other is probably not something I would bank on. Plus the boundry effects below 400hz adds a lot of “sensitivity “ <AT LEAST AT THE NARROW COMB FILTER PEAKS> 


So no! This is very good accurate Way of understanding how things work but honestly I would never put my money into an amplifier that’s half the power thinking that my sensitivity numbers are going to actually work in a car unless you really like wasting money on large amplifiers in the low frequencies what do I mean, your tweeters need exactly the same amount of power as your mid base no questions asked


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## sprexumn

Great info in this thread. 

But I think I found a problem with the original post. Alan seems to use the sensitivity figures to determine actual audio output per watt, ignoring crest factor. Crest factor is the difference between peak and average power level. For music it can be 12-20 dB. So in the most dynamic music the 20 dB difference means an amp that can produce 200w peaks will only be producing 2 watts of music output. Or to put it another way the 2000w average the article says will be needed for 109 dBSPL music becomes 200,000w amp peak power capability.

Now I know y'all will say there's no such thing as too much power, but if you can destroy a speaker with a 100w clipping amp I guarantee I can destroy it quicker with a 200,000w amp unclipped.


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## oabeieo

sprexumn said:


> Great info in this thread.
> 
> But I think I found a problem with the original post. Alan seems to use the sensitivity figures to determine actual audio output per watt, ignoring crest factor. Crest factor is the difference between peak and average power level. For music it can be 12-20 dB. So in the most dynamic music the 20 dB difference means an amp that can produce 200w peaks will only be producing 2 watts of music output. Or to put it another way the 2000w average the article says will be needed for 109 dBSPL music becomes 200,000w amp peak power capability.
> 
> Now I know y'all will say there's no such thing as too much power, but if you can destroy a speaker with a 100w clipping amp I guarantee I can destroy it quicker with a 200,000w amp unclipped.



Ha! Clever .....  

It’s like , let’s say you have a Twitter with a sensitivity of 90 DB , but the manufacturer doesn’t tell you that sensitive your reading was done at let’s say 3500 Hz..... 

So you go to tune your car and lo and behold you have a 10 DB Peak at 3500hz, 
You EQ down that peak. And you’ve just equalized away all your efficiency...... 

I’m sure the room adds some of that peak but I’m also sure the speaker itself in the crossover also probably have some of that peak the only one way to tell is to measure.... regardless your EQ in down peaks or boosting where there’s not peaks either way is a cut in sensitivity for bandwidth.


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