# Underpowering...



## ItalynStylion

.....will never blow a speaker. No speaker, in the history of the universe, has ever failed because it didn't have enough power.

[/thread]


----------



## Gas Is Expensive

ItalynStylion said:


> .....will never blow a speaker. No speaker, in the history of the universe, has ever failed because it didn't have enough power.
> 
> [/thread]


Sure. But insufficient power can often lead to user error.


----------



## darkfrog

ItalynStylion said:


> .....will never blow a speaker. No speaker, in the history of the universe, has ever failed because it didn't have enough power.
> 
> [/thread]


Is that really a myth or a misunderstanding of what is being said? 
IOW, an underpowered amplifier will clip at much lower volumes than a more powerful amp, causing the lower powered amps to be responsible for speaker damage.


----------



## pikers

Lack of power results in user error from excessive gain boosting, bass boosting, and other compensatory actions. These things can result in speaker damage.

If you took a 100w speaker and simply played music through it flat with proper gain settings, then no, it shouldn't blow. Sound might blow though.:worried:


----------



## Gas Is Expensive

pikers said:


> Lack of power results in user error from excessive gain boosting, bass boosting, and other compensatory actions. These things can result in speaker damage.
> 
> If you took a 100w speaker and simply played music through it flat with proper gain settings, then no, it shouldn't blow. Sound might blow though.:worried:


Exactly. And to post "[/thread]" as the OP did is somewhat irresponsible (as if it would make any difference). There are plenty of noobs here who might get the wrong idea from the OP and end up with damaged equipment.


----------



## damage

Underpowering a speaker can, and often is, the cause of blown tweeters. Not to mention the risk to midranges and sometimes even woofers.

Only takes one link to clear this up:
Why Do Tweeters Blow When Amplifiers Distort?


----------



## normalicy

True, it is in fact due to ignorance. But you gotta admit that there is much ignorance in this field by end users.


----------



## illcrx

You can put as much power as you want to a speaker as long as the signal out of the amplifier does not distort and the driver doesn't reach its mechanical limits.


----------



## kyheng

Well, I like to see when the amp starts to discharge DC power on speaker outputs...


----------



## bradsk88

The problem is that underpowering is usually poorly defined. People think "If I put this small amp on my big speaker, it will blow the speaker" Where in reality what it means is "if you buy this small amp, it probably won't be powerful enough to get the volume you expect out of this big speaker, so you'll probably push it past it's limit and into distortion"


----------



## illcrx

kyheng said:


> Well, I like to see when the amp starts to discharge DC power on speaker outputs...


Hmm sounds like a broken amp, or a very bad song.


----------



## kyheng

Nope, not really.... Tried on a 22W amp to power a 50W midbass and hitting the midbass's FS value...


----------



## jibberjive

illcrx said:


> You can put as much power as you want to a speaker as long as the signal out of the amplifier does not distort and the driver doesn't reach its mechanical limits.


*and as long as the driver doesn't reach it's thermal limits. It's possible for a speaker to have clean power and be within it's mechanical limits, but outside of its thermal capacity.


----------



## n_olympios

damage said:


> Underpowering a speaker can, and often is, the cause of blown tweeters. Not to mention the risk to midranges and sometimes even woofers.
> 
> Only takes one link to clear this up:
> Why Do Tweeters Blow When Amplifiers Distort?


That's clipping though, not underpowering. The fact that the one is a result of the other is another matter.


----------



## 22689

Under-power your amp ( Starve it ) and You will have problems.

Under powering your subwoofer or any speaker: Seems pretty funny to me since most everyone is not going to turn their system on with the damned thing turned up so it just pops on. 

if Under powering your speaker blows them then they are being damaged every time you turn them on and listen at low volume for any length of time. ( Makes no sense see?) 

Check this out though. personal experience. 

An Installed daily runner at lower power : let's say an L710d4 wired to 8Ohms on a ZR360 rated @ 550 watts @ 4ohms Mono. This set up ( providing power is sufficient to the amp) Should provide 275 watts of super clean power to that sub. If That sub is Vented - this is plenty of power! That subs rated while in a sealed enclosure and with zero back pressure 275 is more than enough to push it past under powered status. 

Run that same Set up in a sealed enclosure and it will still beat and it will do it all day long for years on end without fail. BUT - The Point - if you run that sub like that for years like I said - 

if you ever decide to use it for something else you will need to really watch it. And extremely long "RE Break In" Period has to occur. I say RE Break in because it's already been playing for years.

the pole piece grooves for this subs coils are broken in super well in the lower end. but they aint even used in the upper! It's like Honing the bottom half of all the cylinders in your engine and expecting the rings to just glide right up the step you made by not doing the entire cylinder. 


Anyway. Might save some one a beloved subwoofer someday and that's why i wrote this. I lost one due to this very thing happening.


----------



## tornaido_3927

n_olympios said:


> That's clipping though, not underpowering. The fact that the one is a result of the other is another matter.


Exactly this.

It's akin to saying that running your speakers at really low volume all the time will kill them. People not smart enough to keep their amps from clipping is different from sending a small signal to a speaker that can handle a large signal.


----------



## Z80_Man

Yes, clipping is the problem here. People using insufficiently powerful amps will want to hear louder and saturate their amp input.

Another problem, when it comes to subwoofers (woofers too, BTW), is damping : pushing the amp to its extreme limits won't do much good either.

So always go for a more powerful amp than theorically necessary, and you won't use it where it clips or produces too much distorsion.

People seem to have hard times tuning their input gains, too. I even heard about someone who lowered them so he tuned his Alpine source's volume knob to 35 (max on Alpines) for normal listening !

Though I agree Alpines are a bit lazy under the 18-20 volume position, I think they would potentially produce harmonic distorsion at the 35 position, and anyway, their outpout will most probaly heavily clip in case of a sudden high level signal incoming from the CD. At the other end, the result could be catastrophic for the speakers... And for the listening quality anyway.

With a nominal 4 V output level, for instance, I generally just start putting the amps' gains settings to 4 V... And it's just fine to play between 1/2 to 2/3 of the max volume level at the source in all usual cases.

Then you can still fine tune if you can find a better setup... But It's generally just there, or very close.

Amplifiers input are actually just unity gain preamplifiers, so you actually just can damp them from the same power as the input signal (just going from a high impedance to a low one) down to 0.

The're absolutely not intended to be used as volume settings or bass boosters, as I frequently notice ! 

Their purpose is just to match the source's output level to the amplifier's inner amplifier stage's input level, so the signal won't clip nor be weaker than the surrounding electrical noise, period.


----------



## coyote-1

The REAL problem is that factory audio systems are virtually designed to get blown. When you can comfortably talk over Black Sabbath or Public Enemy at their loudest, the user is inevitably gonna seek to boost things - thus clipping the amp, thereby driving speakers past their thermal and/or mechanical limits.


Z80_Man said:


> Yes, clipping is the problem here. People using insufficiently powerful amps will want to hear louder and saturate their amp input.


So really, you need this combo:
a) amplifier(s) that can produce the desired volume without clipping
b) speakers that can handle that power level

Unfortunately, the audio industry hardly ever makes that clear. Such phrases as "max power" "continuous power" RMS power" "program power" "peak program power" "peak power" all float somewhat interchangeably in the manufacturer's specs. We have the same problem in the music equipment industry, with PA speakers & floor monitors constantly getting fried and power amps blowing up. All the end-user usually wants is to hear his music loudly and cleanly.... the marketing divisions make the process of getting to that point a bewildering experience.


----------



## Oliver

*Read it and see if you can figure anything out !*



> Manville on *average power over time*:
> 
> The only thing that thermally damages speakers is power... more specifically: average power over time.
> 
> I'll explain...
> 
> If you take a given amplifier, let's say 100 watts and operate it just below clipping with music material, the "Crest Factor" of the amplifier's output is equivalent to the "Crest Factor" of the program material.
> 
> "Crest Factor" is the difference between the average level of the signal and its peak level. For example, a pure sine wave has a "crest factor" of 3dB, meaning that it's peak level is 3dB higher than its average level. We all know that 3dB represents a power factor of 2, so another way to look at it is that the peak power of the signal is twice that of its average level. So, if we play a sine wave on our 100 watt amplifier, just below its clipping level, the average power (over time) the speaker is needing to dissipate is 50 watts.
> 
> A true square wave, by comparison, has a crest factor of 0db, so it has equal average and peak power. Our 100 watt amplifier, playing a square wave, unclipped, into our speaker requires that the speaker dissipates 100 watts of power (twice the heat as a sine wave).
> 
> Music has a significantly higher crest factor than sine waves or square waves. A highly dynamic recording (Sheffield Lab, Chesky, etc.) typically has a crest factor of 20dB or more, meaning that its average power is 100 times lower than its peak power. So, if we play our 100 watt amplifier just below clipping with the typical audiophile recording our speaker is only needing to dissipate 1 watt of average power over time.
> 
> Modern commercial recordings typically exhibit crest factors of around 10dB, meaning that the average power is 10 times lower than the peak power. So, our 100 watt amp just below clipping would deliver an average power over time of 10 watts that the speaker has to dissipate.
> 
> Okay, so what happens when we clip the amplifier (which we all do at times). When the amplifier enters into clipping, the peak power no longer increases, but here's the KEY... THE AVERAGE POWER CONTINUES TO INCREASE. We can often tolerate a fair amount of clipping... as much as 10 dB or more above clipping with a reasonably dynamic recording... a bit less with a compressed commercial recording.
> 
> So, if we turn the volume up 10dB higher than the clipping level with our Sheffield Lab recording, we have now reduced the crest factor of the signal reaching the speakers by 10dB... so instead of needing to dissipate 1 watt average, we are asking the speaker to dissipate 10 watts average, and we're probably ok.
> 
> If we turn up the volume 6dB past clipping on a compressed commercial recording (or bass music recording), we have taken the crest factor of the signal from a starting point of 10dB to only 4dB, asking the speaker to dissipate an average power of 40 watts instead of 10 watts... that's FOUR TIMES the average power, which generates four times the heat.
> 
> SO, in most cases, the reason clipping can damage a speaker really has nothing to do with anything other than an increase in average power over time. It's really not the shape of the wave or distortion... it's simply more power over time.
> 
> When someone plays Bass Mekanik clean (unclipped) on a 1000 watt amplifier the average power is 100 watts (10dB crest factor). You can also make 100 watts average with Bass Mekanik by heavily clipping a 200 watt amplifier.
> 
> If someone is blowing a woofer with 200 watts of power due to a lack of restraint with the volume control... they will blow it even faster with a 1000 watt amplifier because they will probably turn it up even more and now they have more power to play with... this is the recipe for aroma of voice coil.
> 
> When woofers are rated for power, an unclipped signal is assumed. We use test signal with a crest factor of 6dB for power testing and can run a speaker at its rated power for hours and hours on end without thermal or mechanical failure. For example, a W1v2 can dissipate 150 watts average power for eight hours or more with signal peaks of 600 watts. So, we rate the speaker for 150W continuous power. This way, when a customer needs to choose an amp for it, they will hopefully choose one that can make about 150 W clean power... Even if they clip the bejeezus out of that amplifier, it is unlikely that the speaker will fail thermally. This is a conservative method, but it needs to account for the high cabin temperatures in a car (think Arizona in the summer) which significantly impacts heat dissipation in the speaker. A top plate that starts at 150 degrees F is not as effective at removing heat as one that starts at 72 degrees F in the lab... and this affects the ramp up of heat in the coil.
> 
> DISCLAIMER: The frequency components of clipping can affect tweeters due to their low inductance and lack of low-pass filtering. Clipping essentially raises the average power of high frequencies to a point that can damage tweeters... Woofers and midranges couldn't care less about these high frequency components because their filtering and/or inherent inductance knocks that stuff out of the picture.
> 
> Best regards,
> 
> Manville Smith
> 
> Just an absolutely TO-The-POINT explanation!


*Don't think this will help anyone as it is from years ago ... but here goes !*
___________________________________________________________


> Load impedance optimization is what everyone seems to be confused about, so let's discuss it more specifically.
> 
> If you ask an engineer to design a "500 Watt amplifier", you are likely to get a few questions back, but the first one will likely be "at what impedance load would you like the 500W to occur". The answer to this question will determine several design parameters of the amplifier and power supply circuits.
> 
> *If the answer is "1 ohm", then the amplifier must be designed as a "high-current" design, which means it will make its 500W at 1 ohm (meaning a rail voltage of 22.3 V and 22.3A of current capability).*
> 
> If the answer is “I want 500W at 4 ohms.”, then the design needs to have a higher rail voltage and less current capability (44.7V and 11.2 A). In either case, we’re designing a “500W amplifier”, but certain aspects of the power supply and other parts of the circuit need to be adjusted depending on the load and whether more voltage or more current is required to make 500W.
> 
> The high-current version might be a little more expensive to make, but the two amps (1 ohm or 4 ohm) are going to be close in cost and similar in design.
> 
> Now, inevitably, a ‘creative thinker’ comes along and wonders what happens when we take the amp designed to make 500W at 4 ohms and connect it to a 1 ohm load! Well, since it has 44.7V rails and is not a sentient being, this amp will try to deliver 2000W into a 1 ohm load, which requires 44.7A of current… and here we have a problem as the designer never intended it to be able to do this and the amplifier gets really pissed off and hot and either shuts down to protect itself, blows a fuse or catches on fire.
> 
> Now, most car amplifiers are designed to produce optimum (highest stable) design power at 2 ohms, so if we follow that approach for our “500W” amplifier, we would specify a rail voltage of 31.6V with 15.8 A of current capability. If we try to load the amplifier down to 1 ohm, it will run out of current, so we put in a protection circuit to shut it down or mute if someone tries to do that. If you put a 4 ohm load on the amp, the 31.6V rails translate to 250W and the current demand goes down to 7.9 Amps. At 4 ohms, the amp is cooler than the other side of the pillow and cruising well below its capabilities, and we only get half the power output that it is truly capable of.
> 
> Now, the marketing guy says… “Perfect! We will call this a 250W amplifier and then tell people they can DOUBLE THEIR POWER to 500W at 2 ohms… woohooo, it’s like a 2 for 1 sale!” The engineer might say… “Well, at 4 ohms, you’re really not getting the power the amp is designed to produce, but go ahead and rate the amp any way you want, you silly marketing twit.” << and this is how we’ve all become accustomed to understanding amplifiers and how they behave into different loads. We’re all told that power increases at lower impedances, but it’s actually more correct to say that power output decreases at higher impedances (taking the optimal design power as the baseline figure).
> 
> Okay, so hopefully that explains the basics of an amplifier with a singular rail voltage.
> 
> Now, somebody who thinks a little deeper comes along and says. “You know, it sure sucks that we have to load the amp down to get all the power that was designed into it. It would be great if we could tell the amp what the load is so that it can always make its full power.” A well-meaning engineer overhears this reasonable request, and says… “We can do that! We’ll simply put a switch marked “2 ohms or 4 ohms” and let the user select the appropriate position for his application. The switch will lower the rail voltage at the 2 ohm position so the amp is still 500W and doesn’t catch on fire. (Soundstream and Sony did this a while back).
> 
> Seems like a really smart, reasonable solution to give the customer the 500W he paid for every time, right? Only one problem: the amp gets louder when you put it in the 4 ohm switch position and connect it to a 2 ohm load, *and someone posts that on DIYMA and everybody starts to do it, and pretty soon everyone is complaining that the amp is a P.O.S. because it catches on fire.*
> 
> 
> Best regards,
> 
> Manville Smith
> JL Audio, Inc.


----------



## [email protected]

1 unclipped watt wont blow any speaker, doesnt matter if the speaker takes 10000 watts rms


----------



## CBRworm

Too much power kills them, too little power kills them; These things are more trouble than they are worth.

As an aside, I have blown many tweeters in passive systems by clipping amps of high and low power. Since going active many years ago I have not damaged a tweeter. I have never damaged a good midbass driver or woofer with too much or too little power, usually when I start to smell them I turn it down a hair. In my home I have melted my share of Infinity polydome midranges due to them not being able to take the heat well before clipping.


----------



## chad

kyheng said:


> Well, I like to see when the amp starts to discharge DC power on speaker outputs...





illcrx said:


> Hmm sounds like a broken amp, or a very bad song.


Exactly, CLIPPING IS NOT DC!!!!

CLIPPING IS NOT DC!!!!

CLIPPING IS NOT DC!!!!

CLIPPING IS NOT DC!!!!

CLIPPING IS NOT DC!!!!

CLIPPING IS NOT DC!!!!

If that waveform crosses the zero point and goes negative, no matter what shape the waveform is, it's NOT DC, it's alternating current.

Even then, pulsed DC does not mean instant death, it just means the driver only moves one direction. IF it's flat out filtered DC... well... that can be bad as long as the power input is more than that of which the motor structure can wick away from the coil at a standstill.


----------



## gijoe

It's important to understand that clipping is NOT underpowering. Clipping is overpowering. If you destroy a speaker with a clipped signal, you didn't underpower it. You gave it too much power over a specific length of time and it overheated.


----------



## sqshoestring

Holy cow its Chad

I always run caps on tweeters (even active), if your amp puts out DC for some reason it will smoke them and it can help with clipping too.

It also depends on your setup, I mean I had quad infinity 12s IB on my kicker 700.5 at 420rms. They were rated 150rms when IB, 300 in a box. So thats 600rms getting only 420. I could clip them hard and they didn't care, I did it to see how high I could get a clamp on to peak, it was 74A into the kicker. However, the amp didn't clip that hard on the subs anyway, I mean it didn't sound that distorted. Could be because I had two 50Hz low pass on it, still I didn't hear a lot of higher harmonics. I highly doubt they were at xmax, but it was louder than I played it in use. That was using a bass music CD, the highs I kept under clipping as I always did you could hear them clip instantly with that amp.

Most of what I read says you (your amp) can present around double the power to the speaker when clipping, if that were true you could not fry a speaker with an amp rated half or less. But that does not discount if the speaker is cooling properly, has enough cone movement, on the clipped signal...though most seem to say they will.


----------



## Z80_Man

Of course unclipped watts would blow a speaker, but you'll have to push it pretty far to the limits to achive this, and it's unlikely your ears can bear it anyway ! 

When I was talking about the necessity to overpower an amp (and Oliver's quote perfectly explained why you should not rely on the announced power on the box), I was thinking about normal listening use only (I can't think differently, sorry, I'm not a SQL contest competitor ! )

You really have to avoid any part of your audio setup to clip or to distort too much. And yes, of course, not to overdrive your speakers.

But too much watts will have a different behavior : they will just move the speaker too much until it may blow, but it will be a mechanical blow (the coil will be pushed out of it trail).

Clipping, on the other hand, will really produce DC by flattening the peaks, the more the overdrive, the longer the flattening.

Amplifier cells actually may only produce voltage between their minimum and maximum power supply. Any signal that will saturate their input will result into producing a continuous flat output signal at maximum voltage until the input signal drops back.

Now, if you woofer can resist or not to this treatment is just a matter of how long will its coil to resist before it just burns.

As long as the current (or voltage) is varying, the counter-electromotive force induced in the coil will oppose the current variation, creating enough impedance.

But clip for a too long time... And your coil will just behave accordingly to its true nature : a length of thin copper wire, with a resistance of only a few ohms... You can as well call it a lamp's filament, without the oxygen-free environment to prevent it from burning !

A tweeter will burn in a fraction of a second if exposed to just a too low unfiltered frequency... A sub is of course much tougher, but won't stand infinite lasting DC either.


----------



## chad

Z80_Man said:


> Clipping, on the other hand, will really produce DC by flattening the peaks, the more the overdrive, the longer the flattening.


No, it will produce DC after the amp blows up and dumps one full rail into the VC, until then it's not DC, unless it's at least half-wave rectified.

this is DC :









This is not DC: 









NO MATTER WHAT THE WAVEFORM SHAPE IS, IF IT IS NOT ALTERNATING... IT'S DIRECT.


----------



## Z80_Man

You didn't post the right pictures (except for the square waves), mate. 

This is the right one :










Any flat on the curve is actually direct current. Your square wave example is actually just polarity changing DC... The only transient state in such a signal is when inverting occurs.

BTW, a scope won't show you such a perfect steep slope, but will rather display some curved angles and a stiff but slightly bent slope :










Anyway, that's the reason why tweeters will blow when applied too low frequencies : at the top of a sinus curve, the current changes so slowly that the CEMF effect almost disappears for a short time. It becomes near enough to DC to blow the ultra thin coil.


----------



## chad

Z80_Man said:


> Any flat on the curve is actually direct current.


Nope

Any part of any waveform on one side of the X axis is DC, you posted an AC waveform, and did not read my rectification stipulation, hence the first pic 

As soon as it completes a cycle, or even crosses the X axis, square, sine, sawtooth, spaghetti monster.. it's AC.

Look it up

Please.


----------



## t3sn4f2

I think Chad's saying that it should not be called DC because it is not DC by definition. 

As for a tweeter blowing from too low a frequency? I don't know about that. Don't they blow for the same reason that all other speakers blow? Any combination of too much power over time or reaching it's mechanical limits severly or too often? You could put 500Hz through a tweeter all day long, so long as you don't exceed it's xmax. Thermal issues won't even come into that picture.


----------



## Z80_Man

I just said the direct part could last long enough to blow a coil.

The AC part only occurs when the voltage value is evolving.

If you filter a clipped signal with, say, a capacitor in serial, it will remove the continuous signal and keep the AC part intact.

In the clipped signal picture I posted, imagine the flat tops are removed, leaving a pit down to 0 V instead, with a slope stiffness depending on the filter used (for just a capacitor, it won't be so steep, and won't probably reach 0V if the clipper is short).

But the removed part was indeed real DC.


----------



## chad

The tweet is blown from the ringing of the clipped waveform. Harmonics, overshoot, you name it. Thus is why often times preamp clipping is worse than power amp clipping. power amps clip more gracefully than a ****load of op-amps.

See that flat spot fatten up (and overshoot on the bottom?) If you brought the time/div up (down/faster) you would see some nasty stuff in there.










It's still not DC, you cannot call it DC it's a COMPLETELY incorrect term... Let's settle on square wave or clipping 

BTW, That's not my pic,I nabbed it here and I can't remember from whom, I added the circles. Please forgive. I use leader analog scopes


----------



## IBcivic

sqshoestring said:


> Holy cow its Chad


probably just a cameo apperance:laugh:

EDIT; He really is back!


----------



## Z80_Man

t3sn4f2 said:


> I think Chad's saying that it should not be called DC because it is not DC by definition.


Taken separately, each constant voltage part of any signal is DC.

The effect on a speaker (or amp) is just a matter of how long it will last, and the device's thermal absorption ability.

After all, clipping is commonly used to color electrical instruments sounds (such as electric guitars). But it's never applied to the speakers. It's driven to the input of the next amplifier stage, an amp able to absorb the clipped signal without failing. When the result is sent to the speakers by the last amplifier stage, it's never overdriven past the amp's voltage ability.



t3sn4f2 said:


> As for a tweeter blowing from too low a frequency? I don't know about that. Don't they blow for the same reason that all other speakers blow? Any combination of too much power over time or reaching it's mechanical limits severly or too often? You could put 500Hz through a tweeter all day long, so long as you don't exceed it's xmax. Thermal issues won't even come into that picture.


Thermal issues are just a consequence of applying DC for too long in this case

Of course, you can blow any speaker with too much power (thermal issues too, plus electromechanical forces).

But you can blow a tweeter easily by sending it 40 Hz without even reaching half of its power handling. Just try !


----------



## chad

Z80_Man said:


> Taken separately, each constant voltage part of any signal is DC.


NO NO NO, 

ANYTHING ON ONE SIDE OF THE X-AXIS IS DC, NO MATTER WHAT THE WAVEFORM LOOKS LIKE. What you see as DC in said time base.. Guess what? That portion of a sinusoidal wave is DC too.

Rectified sine wave is DC, rectified square wave is DC, full wave square wave is AC, this is not rocket appliance and a tweeter WILL NOT blow feeding it a square wave given the signal is within it's thermal capabilities.


----------



## chad

Z80_Man said:


>


That's so ugly that I bet it sounds cool, what was it?


----------



## Z80_Man

chad said:


> The tweet is blown from the ringing of the clipped waveform.


OK !

I just wanted to warn on the danger of long lasting constant voltage parts when applied to a speaker coil.

Note that sometimes, a signal can contain another continuous part : it's an offset affecting all the signal (a real DC part adding to an AC part). That's why capacitors are present at the devices' inputs to eliminate it.


----------



## Z80_Man

OK, Chad, bad term, my apologize.

In french, we only the term "continuous current" for any constant voltage of any sign, opposed to "alternative current" of any shape.

That's where I misused the term "DC". I think our langague really lacks precision, as we don't have so many specific terms.

Sorry again !

So please, what term do you commonly use for "constant voltage" in English ?


----------



## chad

Z80_Man said:


> OK, so don't call it DC if you want !


Perfect  We agree to disagree, Love it.



Z80_Man said:


> I just wanted to warn on the danger of long lasting constant voltage parts when applied to a speaker coil.


Absolutely, I agree. I like to look at it as the lack of lower voltage parts 



Z80_Man said:


> Note that sometimes, a signal can contain another continuous part : it's an offset affecting all the signal (a real DC part adding to an AC part). That's why capacitors are present at the devices' inputs to eliminate it.


And sometimes thru the entire signal path at times. 

Then we have direct coupled amps... Gawd I love those. Put DC in, get DC out. Perfect for powering your vibrating bed, shaker table, you name it. Also notorious for setting speakers ON FIRE... Subsequently the amp catches on fire sometimes too.

I have more than a few of those here.

In fact the Technics amps I have here (lemme go look at the model) SE-9060, you can select full direct coupling or some cap coupling that limits you to (gasp) a 10 cycle LF limit :mean:


----------



## SoundChaser

chad said:


> That's so ugly that I bet it sounds cool, what was it?


Looks like a digital signal. I don’t think that’s an analog signal severely clipped. The rise and fall are too steep.


----------



## chad

digi would hopefully be more square.. depends on freq.

Many if not most amps will do a perfect square wave. That's why I asked, I'd like to see it driven just a BIT harder... Ala Reznor.


----------



## sqshoestring

chad said:


> That's so ugly that I bet it sounds cool, what was it?


That looks very much like one side of a PWM power supply signal. As in a TL494 IC running a bank of mosfets in a car amp. I've never listened to it, but seen in on my scope plenty of times. The timing is usually off just a little, so when you put the opposing waves together both are not on at the same time. If you look closely that wave is different size at top and bottom. I have a photo of both waves someplace. Here is one likely at the mosfets so its not as pretty looking in-circuit. You can see how they don't overlap or the power supply would instantly smoke. This is an old JBL car amp, a GTQ200.


----------



## chad

if you shift one side a half a cycle, that would be so sexy in a synth sample.

Rebuilding the 80's


----------



## SoundChaser

2 gigabit per second data stream
12.5Gb/s data stream
12.5Gb/s Pseudo-Random Pattern


----------



## ItalynStylion

This is why I was hoping we'd stop at the first post...lol! Sorry, went out of town for a week and forgot I'd posted.

So to summarize what we've learned.

Under powering the SPEAKER is harmless
Asking an under powered amp to make more power than it's able to is BAD NEWS BEARS!
Clipping = Speaker Poison
Keep your drivers within Xmax and their thermal limits and you'll be fine.


----------



## tornaido_3927

ItalynStylion said:


> This is why I was hoping we'd stop at the first post...lol! Sorry, went out of town for a week and forgot I'd posted.
> 
> So to summarize what we've learned.
> 
> Under powering the SPEAKER is harmless
> Asking an under powered amp to make more power than it's able to is BAD NEWS BEARS!
> Clipping = Speaker Poison
> Keep your drivers within Xmax and their thermal limits and you'll be fine.


and /thread


----------



## Spooln2

This is great info but my experience is: My wife was watching Purple Rain on TV and cranked it up. I was upstairs and it sounded like bad low end thumping. I ran downstairs and my speakers were clipping like crazy. But with albums or cds, I can play them plenty loud. So it was the source in this case. But the tv runs thru the amp. I had a Fleetwood Mac album that would also clip when turned up and really not that loud. It could be that she turned the tv(thru the amp) too quickly. The good news is the speakers survived. So did my wife.


----------



## ItalynStylion

^Different sources output different voltages. Sounds like your TV has a higher level output than whatever else you usually use.


----------



## cgarnes

Not sure why everybody has to be so damn scientific about it. Does lack of power blow the speaker? NO! But, it does lead directly to the speaker being blown! 
News Flash! People like to turn their stereos up LOUD! When you try to get a lot of signal out of a small amp it begins to distort a heck of a lot sooner than an amp rated with more power. (all things being equal). Why can't we all just agree that what blows speakers is generally DISTORTION. Easiest way to create distortion... Not enough power...


----------



## Oliver

cgarnes said:


> Not sure why everybody has to be so damn scientific about it. Does lack of power blow the speaker? NO! But, it does lead directly to the speaker being blown!
> News Flash! People like to turn their stereos up LOUD! When you try to get a lot of signal out of a small amp it begins to distort a heck of a lot sooner than an amp rated with more power. (all things being equal). Why can't we all just agree that what blows speakers is generally DISTORTION. Easiest way to create distortion... Not enough power...





> Why can't we all just agree that what blows speakers is generally *DISTORTION*.


Like when Jimi plays ? YouTube - Jimi Hendrix - Voodoo Child

I love his music , but ... I have to throw away my speakers after I listen to him


----------



## coyote-1

Which means that, in cars, the flaw lies with the factory system design (and system designers).

I've always wondered why audio upgrades were not part of the factory plan. I mean they DO 'upgrade' these things, but usually only by adding features such as USB input or something. Rarely do they give you serious sound from the factory.

I'm in the process of adding $600 or so to my car to make the audio sound good. I'm pretty sure that, had the dealer offered a truly powerful/loud/clear system that wouldn't blow up, I'd have been willing to spend another thousand to avoid doing what I'm doing now.


cgarnes said:


> Not sure why everybody has to be so damn scientific about it. Does lack of power blow the speaker? NO! But, it does lead directly to the speaker being blown!
> News Flash! People like to turn their stereos up LOUD! When you try to get a lot of signal out of a small amp it begins to distort a heck of a lot sooner than an amp rated with more power. (all things being equal). Why can't we all just agree that what blows speakers is generally DISTORTION. Easiest way to create distortion... Not enough power...


----------



## chad

coyote-1 said:


> I'm in the process of adding $600 or so to my car to make the audio sound good. I'm pretty sure that, had the dealer offered a truly powerful/loud/clear system that wouldn't blow up, I'd have been willing to spend another thousand to avoid doing what I'm doing now.


The auto maker has to draw the line somewhere between price and who will actually take advantage of what the arbitrary person will define as "loud." 

We ALL do this in this hobby, we have to. We generally build what suits our needs, whereas an auto maker has do define and build into their cars what the majority of their target market will be happy with.

That's why they don't shove corvette drivetrains in Buick grandmamobiles 



cgarnes said:


> Not sure why everybody has to be so damn scientific about it.


I can't believe someone actually posted that. Why NOT be specific?


----------



## chad

cajunner said:


> square waves are hard for amplifiers to drive, right?


Nope, not good ones.



cajunner said:


> speakers don't like square waves either, correct?



They can take it just fine, no reason they couldn't as long as the maximum power does not reach the point that the voice coil can shag heat.



cajunner said:


> so don't play 'em!


Why?



cajunner said:


> don't play 'em low, don't play 'em high, hide your kids, hide your wife...



We have for ages, and probably will still, the 80's was popular for the square wave.

YouTube - Roland D-50 Square Wave

Holy ****, my vintage AR speakers in my office just handled that, and to think that they are not even "digital ready!"


----------



## Dangerranger

cgarnes said:


> Why can't we all just agree that what blows speakers is generally DISTORTION. Easiest way to create distortion... Not enough power...


Because distortion doesn't kill speakers. Too much power kills speakers. Exceeding a speakers thermal or mechanical limits kills speakers. Speakers don't care how much distortion an amplifier is producing. Look at distortion pedals used in concert, or guitar amps in general. They introduce huge amounts of distortion into a signal and don't kill speakers. Distortion simply introduces a lot of harmonic content into the signal that shouldn't be present. That's not to say that a clipped amplifier doesn't produce a ton of distortion, or that distortion isn't present when an amplifier is overdriven or a speaker is blown, but the distortion isn't the cause of a speaker blowing.


----------



## kvndoom

coyote-1 said:


> Which means that, in cars, the flaw lies with the factory system design (and system designers).
> 
> I've always wondered why audio upgrades were not part of the factory plan. I mean they DO 'upgrade' these things, but usually only by adding features such as USB input or something. Rarely do they give you serious sound from the factory.
> 
> I'm in the process of adding $600 or so to my car to make the audio sound good. I'm pretty sure that, had the dealer offered a truly powerful/loud/clear system that wouldn't blow up, I'd have been willing to spend another thousand to avoid doing what I'm doing now.


Well for the typical car market, they throw in about 75 extra dollars worth of stuff that's arguably better than what you can buy at walmart, slap a few "bose" stickers on the speaker grilles, charge an extra 400 dollars over the car's current cost, and the buyers will think it's the best thing since sliced bread.

VW was using Dynaudio for its premium audio, but just announced that its upscale stereos will be branded "Fender" starting with 2012 models. "Fender" as in "Panasonic" 

In Japan, you can buy Subarus with McIntosh amps and speakers as an upgrade. In the US, their upscale stereos are Harmon Kardon, which might be good, might be not.


----------



## DBfan187

sorry bros but clipping isn't DC, the signal still oscillates in both directions so it's AC

remember that if it changes in time, it's not DC


----------



## sqshoestring

DBfan187 said:


> sorry bros but clipping isn't DC, the signal still oscillates in both directions so it's AC
> 
> remember that if it changes in time, it's not DC


Everyone likes to say that, if they never used a scope. So 1Hz AC is fine for a sub because its AC?

Whatever the case, musical signals are not naturally square waves. Some of you are arguing in circles on this stuff; if you buy a X rms amp to run a X rms sub* like many do *and then clip the amp to 2X rms output as many amps can do....then guess what the X rms rated amp might toast the X rms rated sub because the clipping increased the realized current flow through the VC. Its that simple, now you vary the equation by the type of sounds played, the enclosure, ambient temps even, what the amp actually produces clipping, etc, and the sub might take the power it might not.


----------



## chad

DBfan187 said:


> sorry bros but clipping isn't DC, the signal still oscillates in both directions so it's AC
> 
> remember that if it changes in time, it's not DC


We've been over this, and you are wrong too. Pulsed DC changes in time  Unfiltered DC changes in time. It only becomes AC when the POLARITY changes over time.


----------



## cubdenno

chad said:


> We've been over this, and you are wrong too. Pulsed DC changes in time  Unfiltered DC changes in time. It only becomes AC when the POLARITY changes over time.


Pffft!! like you would know....


----------



## DBfan187

chad said:


> We've been over this, and you are wrong too. Pulsed DC changes in time  Unfiltered DC changes in time. It only becomes AC when the POLARITY changes over time.


If it changes in time then it is no longer constant, so how is it still DC?


----------



## DBfan187

one of the best threads on this subject IMHO 

Clipping: damage from power or cone movement - CARSOUND.COM Forum


----------



## chad

DBfan187 said:


> If it changes in time then it is no longer constant, so how is it still DC?


it can change in time all it wants as long as the trace does not cross zero volts (polarity change) 

In your theory everything is AC, because ALL filtered power supplies have at least a bit of ripple at some point  You can find it if you try


----------



## chad

http://www.audiovisualdevices.com.au/downloads/rane/note128.pdf


----------



## 8675309

I agree I have never killed a speaker with low power. Even 18 years of dirty low power has never killed a speaker. 

Now on the other hand I have killed a speaker with lots of clean power! 

I think you have to have a median! You have to know when enough is enough!

You have to know your speakers limits. 




ItalynStylion said:


> .....will never blow a speaker. No speaker, in the history of the universe, has ever failed because it didn't have enough power.
> 
> [/thread]


----------



## Z80_Man

My speaker limits don't have to exceed my ears' anyway ! 

I clearly don't want to underpower my Utopias and get rubbish sound, and I overpower them on purpose.

Anyway nobody else than myself has to put his paws on my babies !


----------



## sqshoestring

cajunner said:


> Square waves aren't any better or worse, some say, but it's the type of waveform that keeps a coil stationary for longer periods that does the trick, and that's not just because of energy through the coil, that has to do with heat dissipation and other stuff, like glues and former thickness/material, etc.


The consensus I found was that in music the cone does not stand still with square waves/clipped waves and it cools just fine. But the increased energy under the square wave does increase heat, and if it is enough to damage it then you get toast....the wires get hot.


----------



## Z80_Man

Yep, and you can easily have your wires and speaker coils become hot if you're going to steam up the volume yet still get a clear and neat sound, so I certainly won't try to have them becoming hot even at low volume by clipping the signal ! 

I agree distorsion and clipping are commonly used in music, but your Hi-Fi setup is supposed to reproduce that without adding some of its own ! 

BTW, once, again, the output amps don't clip when musicians perform on stage. Distorsion is generally acheived by saturating a preamplifier before feeding another amp stage (the process can even be multiplied several times, as ZZ-Top are known to do).

When thinking about the signal sent to the speakers, you mustn't confuse near-square envelope (yet bounding higher frequencies waves) and flat squared (clipped) output overall signal.


----------



## chad

Z80_Man said:


> BTW, once, again, the output amps don't clip when musicians perform on stage. Distorsion is generally acheived by saturating a preamplifier before feeding another amp stage (the process can even be multiplied several times, as ZZ-Top are known to do).


Actually one of the best sounds you can achieve out of a guitar amp is to drive the preamp clean and drive the piss out of the power section, but this is only a tube amp trick and you are not gonna see hard-edge clipping.

Marshall master volumes heads (AKA Hendrix) and these are fine examples:

Speedster Amplifiers


----------



## Oliver

chad said:


> Actually one of the best sounds you can achieve out of a guitar amp is to drive the preamp clean and drive the piss out of the power section, but this is only a tube amp trick and you are not gonna see hard-edge clipping.
> 
> Marshall master volumes heads (AKA Hendrix) and these are fine examples:
> 
> Speedster Amplifiers


Deluxe 25 watt amplifier head only
Hotrod purple paint

$2,049.00


----------



## sqshoestring

Tube amps clip differently to make their kind of sound, it can be done solid state but I've never seen a normal car amp with those capabilities. Tubes round the wave somewhat like compression does, it is not flat. Some car amps are in between.

In a nutshell you will get more power within a clipped or compressed signal, because the wave spends more time at high output. More power will go through the amp and speaker. I don't think you have to worry about speaker wire getting warm unless you use some tiny wire, voice coil wire is far smaller than typical speaker wire and nicely banded together for limited cooling....that is why speakers always fry first. Its all about power, as long as the signal makes the cone move to cool it the speaker does not care what the signal looks like.


----------



## kvndoom

Ricky Doherty said:


> Well for the typical car market, they throw in about 75 extra dollars worth of stuff that's arguably better than what you can buy at walmart, slap a few "bose" stickers on the speaker grilles, charge an extra 400 dollars over the car's current cost, and the buyers will think it's the best thing since sliced bread.


----------



## ItalynStylion

sqshoestring said:


> The consensus I found was that in music the cone does not stand still with square waves/clipped waves and it cools just fine. But the increased energy under the square wave does increase heat, and if it is enough to damage it then you get toast....the wires get hot.


I gotta come back to this for my own benefit.

I thought the length of the flat spot on a square wave actually was the duration of a motionless cone. If the top peak is OUT and the bottom peak is IN....(depending on the phase wiring).....the wave form is the change in motion correct? Meaning that ANY point where it's flat the cone is stopped right?


----------



## sqshoestring

ItalynStylion said:


> I gotta come back to this for my own benefit.
> 
> I thought the length of the flat spot on a square wave actually was the duration of a motionless cone. If the top peak is OUT and the bottom peak is IN....(depending on the phase wiring).....the wave form is the change in motion correct? Meaning that ANY point where it's flat the cone is stopped right?


The cone in a sub can't react that fast, it may change the motion but not that much. If you clip a sub in a BP box for example, you can hardly hear the difference as the box takes out the higher harmonics. I would guess since a sub will not play that high anyway, it does the same with high frequency clipping harmonics but not near as nice as a BP box does. That is the danger of blowing a sub in a BP you can't hear the clipping very well. 

Remember the power input to a sub changes its position, it does not dictate position. If you put a battery on a sub it pops then comes to rest at some place away from center (center=0volts), but even that is going to be slower than say 20Hz or more, depending on the mass of the cone and suspension compliance, etc. 

That might not be true for a mid with a light cone I don't know, but with a typical car sub the cone is not going to stop at musical frequencies.


----------



## ItalynStylion

Yeah, my question rather wasn't does the cone (just that part of the assembly) stops; but rather that the voice coil is being TOLD to stop. So you're agreeing that the motor, on a flat spot of a square wave, is trying to tell the moving assembly to stop. Regardless of whether it listens lol


----------



## sqshoestring

ItalynStylion said:


> Yeah, my question rather wasn't does the cone (just that part of the assembly) stops; but rather that the voice coil is being TOLD to stop. So you're agreeing that the motor, on a flat spot of a square wave, is trying to tell the moving assembly to stop. Regardless of whether it listens lol


No, I'm not making the point very well. If the amp puts out +25V to the sub the sub moves the cone out to wherever the suspension lets it....it does not move to X spot. If the suspension got a tear in it then the cone would move even more. Sure it ends up going to about the same place with the same power applied, but the power makes X force it does not move to X place. The cone stops because of the suspension, not because the VC saw X voltage and not X+1v. So if you drop power on it the cone starts to move and keeps on moving until the suspension overcomes the VC force. Really what tells it to stop is when the power reduces to zero and goes negative. The amp is the major player sure, but with a clipped signal you only have a change in the signal; it still tells the cone to move in/out just not in exactly the right way. I would say the signal inverting is far more powerful than the shape of the signal as it alternates. Technically it is impossible for the sub to move like a square wave; it can't move the cone instantly, and even it if it tried you would have a much higher cone speed and then the mass of the cone would make it more difficult to stop at a particular place. Its kind of like jumping on a trampoline, you can stick your legs out fast when you hit or slower, but you still bounce back up long as you push against the suspension of the trampoline one way or the other.


----------



## tornaido_3927

I originally thought that the cone stopped at the square part of the waveform until a while ago on this forum when someone said otherwise, but I never could figure out how square wave kills a speaker.

If you are looking at the waveform and the Y axis of that is the +/- AC voltage. Then when you have a square wave isn't it just the same voltage if the square bit is at the same level as the peak of the regular waveform?

I hope I'm making sense 

EDIT: Ok so I think I've found my answer..


> In power amplifiers, the signal from an amplifier operating in clipping has two characteristics that could damage a connected loudspeaker:
> *Difference between clipped and maximum unclipped waveforms; Because the clipped waveform has more area underneath it than the smaller maximum unclipped waveform, the amplifier produces more output power.* (See the waveform below for an example.) This extra power can cause damage to loudspeaker components, including the woofer, tweeter, or crossover, via overheating.
> 
> In the frequency domain, clipping produces harmonics at higher frequencies than the unclipped signal. This additional high frequency energy has the potential to damage a loudspeaker's tweeter via overheating.
> 
> Other effects of clipping include:
> Music which is clipped experiences amplitude compression, whereby all notes begin to sound equally loud because loud notes are being clipped to the same output level as softer notes.


----------



## ItalynStylion

^Yeah, think of it like touching a hot stove. A brief moment touching a 200 degree stove and you're fine. But if you touch it and leave your hand there for a period of time you'll burn. The peak temperature (or power in the speakers case) isn't the problem, it's the duration at peak power.


----------



## tornaido_3927

What an excellent analogy, thanks 

Not knowing that has bugged me for a while!


----------



## Oh.humes

TOLD to stop. So you're agreeing that the motor, on a flat spot of a square wave, is trying to tell the moving assembly to stop. Regardless of whether it listens lol.


----------



## Oliver

Oh.humes said:


> TOLD to stop. So you're agreeing that the motor, on a flat spot of a square wave, is trying to tell the moving assembly to stop. Regardless of whether it listens lol.


Instead of a smoothly undulating wave , it is more like get up as fast as you can ... stay ... stay ... down as fast as you can go, rinse and repeat.

the duty cycle changes to 85 % on and 15% off.

Instead of 50% on and 50% off


----------



## Ianarian

I bet the enthusiasts with formal education that read this,.....just want to ring some people's necks. I bet the scientist(can't recall his name) who brought this to a head for us, is probably rolling over in his grave over this thread. Reading people's typed phrases like: "the voltage is pushed", or even making reference to potential from a reading at the speaker, might be taking it a little too far. I understand the voltage/sign wave relation but, the focus has to remain on- how much work can be done at the speaker. Furthermore, its not underpower, clipping, overpower, distortion, blah blah that kills the speaker, I got the reason right here--------> People! and that's all folks. Similar to the gun motto. In the occasion that equipment fails, wondering whether or not you did something wrong is prevented by knowing what you are doing.


----------



## Oliver

I do my subwoofer the same way I start my car.

For my car on 20 degree Fahrenheit mornings . . . I turn the key and floor it for 15 to 20 minutes until the oil flows and I have never had any problems.

So remember . . . just push the pedal to the metal and listen to your motor purr.

:laugh:


----------



## chad

Ianarian said:


> I got the reason right here--------> People!


Ha! And all this time I thought it was due to a nut loose behind the wheel.


----------



## Ianarian

chad said:


> Ha! And all this time I thought it was due to a nut loose behind the wheel.


Oh, hah, no you're right, loose nuts. I was just testing to see if you really knew.


----------



## 14642

OMG. I've never read so much BS in all my life.

Speakers fail in two ways--mechanical and thermal. I assume we're talking about thermal in this thread, because underpowering a speaker (if there is such a thing) certainly won't cause mechanical failure.

Speaker voice coils burn for only one reason--too much power for too long. Saying that distortion blows speakers is an oversimplified way of saying that if you're hearing distortion, it's an indication that your amp may be clipping and providing more continuous average power than it is rated to deliver playing a sine wave and if you've matched the power handling of you speaker to the amount of power the amplifier can provide BEFORE clipping, your speaker may be in danger. 

Distortion doesn't blow speakers and there's no waveform that will burn a coil so long as the continuous average power doesn't exceed what the speaker can handle. DC doesn't blow speakers either--it's just another waveform. 

A square wave is NOT DC, but its duty cycle is the same-- 100%.


----------



## sqshoestring

LOL! Yes "area under the curve". Clipping is more power to the speaker. Did they stop teaching about electricity in schools or what....


----------



## UNFORGIVEN

I vote user error


----------



## chad

UNFORGIVEN said:


> I vote user error


----------



## diynube

Hey guys, I'm new to the forums and I figured I'd chime in. One car audio shop dude told me he could blow any sub by sending it a very quiet distorted waveform... I disagree.
Assuming a constant peak to peak voltage:
A fully clipped waveform (square-wave) delivers 2pi (about 6.28) units of energy in one full cycle.
A perfect sine-wave delivers 4 units of energy in one full cycle.
Therefore, a fully clipped waveform delivers pi/2 times the amount of energy in a given cycle that a sine-wave.
There, an amplifier giving a fully clipped waveform will deliver about 57% more power to a driver than if were outputting a non-clipped sine-wave. 

Does anybody have experience in approximate figures regarding at what RMS power levels a given sub (500W RMS, for example) can withstand a square-wave? 
My theory is that it will be the same or close to the maximum rated power (500W RMS in this case.) 

Hypothetically, an amplifier rated to deliver a perfect sine-wave at 318.3W RMS (500W / (pi/2) ) and distorts to a fully clipped square-wave at 500W RMS, it should still not be able to overcome the thermal limit of the sub and therefore should not blow the sub. 

In short, do subs tend to blow at some point below their rated power when the signal is clipped? The thermal dissipation characteristics might change depending on how a waveform actually allows the sub to move. Therefore, I assume also that the Thiele/Small parameters of the subwoofer and the subwoofer enclosure used would affect what power levels a subwoofer rated at 500W RMS would blow if fed a square-wave.


----------



## mine4118

imeverlast said:


> Under-power your amp ( Starve it ) and You will have problems.
> 
> Under powering your subwoofer or any speaker: Seems pretty funny to me since most everyone is not going to turn their system on with the damned thing turned up so it just pops on.
> 
> if Under powering your speaker blows them then they are being damaged every time you turn them on and listen at low volume for any length of time. ( Makes no sense see?)
> 
> Check this out though. personal experience.
> 
> An Installed daily runner at lower power : let's say an L710d4 wired to 8Ohms on a ZR360 rated @ 550 watts @ 4ohms Mono. This set up ( providing power is sufficient to the amp) Should provide 275 watts of super clean power to that sub. If That sub is Vented - this is plenty of power! That subs rated while in a sealed enclosure and with zero back pressure 275 is more than enough to push it past under powered status.
> 
> Run that same Set up in a sealed enclosure and it will still beat and it will do it all day long for years on end without fail. BUT - The Point - if you run that sub like that for years like I said -
> 
> if you ever decide to use it for something else you will need to really watch it. And extremely long "RE Break In" Period has to occur. I say RE Break in because it's already been playing for years.
> 
> the pole piece grooves for this subs coils are broken in super well in the lower end. but they aint even used in the upper! It's like Honing the bottom half of all the cylinders in your engine and expecting the rings to just glide right up the step you made by not doing the entire cylinder.
> 
> 
> Anyway. Might save some one a beloved subwoofer someday and that's why i wrote this. I lost one due to this very thing happening.



seems to make sense tome...


----------



## deesz

I always thought this was a good article.
Answer


----------

