Welshsox
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Wattage ? Power ? what exactly is it ?
Jan Vigne
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1 - How does the 2000 watts actually increase the power, is there more current available ? are the voltage rails larger ? will it drive a lower impedance ?

You would hope more current is available when stepping from 100 watts to 2k watts but I suppose there could be a fairly puny 2k watt amplifier out there. If you maintain the same class of operation, then the rail voltages must increase to gain that much more available power unless the 100 watt amplifier is wasting large amounts of its power supply. With that much more power available, the larger amplifier should be more capable of driving a lower impedance load but that is not to say any amplifier larger than another will drive low impedance loads better than the other. You are asking about a condition that is not static and therefore not a simple case of delivering more peak current into a resistive load. You really should be concerned with what happens right after the amplifier drives a large amount of current into a low impedance load.


Quote:
2 - How does the power rating of a speaker get involved, i understand that you have say a 200 watt rating on the voice coils but how is this rating actually affecting things. What are the limiting factors ?

The power rating of the speaker is all but inconsequential. Speakers don't got no watts! Ignore the general specs on speakers other than height, width, depth and weight. You need to know whether the speakers will fit where you intend them to sit and if you need to borrow a truck to bring them home. There are a few numbers you would like to know about a speaker but, if you keep both sensitivity and impedance reasonably high, you'll generally do OK with not much more information than I mentioned earlier.


Quote:
3 - What im getting is if you connext a 200 watt speaker coil to a 2000 watt amplifier we know it will work and not burn out. What is causing this the speaker to only draw enough power that it can handle ? obvioulsy wattage is a function of impedance, voltage and current. So im trying to figure out how a more powerful amp on a smaller speaker can work effectively without damaging the voice coil

I'm not sure why you believe a high powered amplifier won't damage a speaker. Are you not powering up the amplifier? Are you asking why it is easier to blow up a speaker with too little power?

CECE
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Much easier to smoke a tweeter with underpowered than high capable watts, I've done it. More watts, more clean signal to teh drivers, it not only sounds better, but keeps drivers from being destroyed. i smoked to ribbon tweeters by actually clipping a 300W per channel amp years ago. When you want realistic listeing levels of a live event it takes more power than you might think. Have yet to do any damage when running with 4800+ W RMS capable with 4 mono Vanalstine P500 MOSFET amps with lotsa capacity to deliver what is needed for realism. Without a large power supply, which an amp is, simply a modulated power supply, it's modulated by teh auido signal from teh pre amp. Just like when the generating plant can't deliver teh power needed on a hot summer 100 degree day, the voltage drops, down from teh nominal 125VAC, to as low as 109 or even less, things start to get damaged, the power amp in an audio system, is teh power supply, it must be capable of delivering the voltage and current needed when called upon. No such thing as too many watts. Good clean un distorted watts. less than .01% FAST 800V uS slew rates, all teh attributes of top quality. Not 3% THD and calling THAT musical and warm, it distortion, and making it's own sound. Guitar amplifiers do that cus' that is creating teh sound, not reproducing it. On ANY speaker the higher powered amp will sound fuller, cleaner, better. Try it power a speaker with 10W, then move to 100W then 500 or more, the higher wattage power supply will be more in control, bass better defined, less wool, cleaner highs etc etc. There is no doubt about it. any one thinking some 8W amp is capable of life like reproduction is really mis guided, and doesn't understand basic electricla parameters. then there is the issue of single driver speakers, more nonsense. That is just not understanding basic physics. Never been to a live event where they had one driver filling a hall, it can't do it, impossible. VTL whom some think are so grand, also beleive in power powr power. I agree, too bad i don't agree that a mere 800W tube amp is worth $24K, and ya need another one for teh system for a mere 1600W, using 24 output tubes, yeah, that's a great design..nope. MOSFETS baby on teh output, more current more reliable, less wasted energy as heat. MOSFETS are teh key. Output tubes are wooly, ill defined bloated, hardly acurate reproduction. Lack of control over teh driver.

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Speakers don't get no watts? Huh? When you apply a volatge across it, and it has current flowing through it's coil, guess what you caclulate? It's simply a matter of higher rated speakers have large coils more coild more drivers that can utilize higher power when needed to produce what volume you are asking for. Watts do matter on speakers. Not just if they fit in a room or not. Man o man. Ever fill a live event large space with speakers rated at 10W capacity, and expect to get 101dB all night long, nope, i ain't seen it done. Better drivers have better coils,larger, higher temperature insulation, better heat disapation as they warm up from being supplied power. Using multiple drivers also allows the system to utilize the larger capacity availabe from the amplifier. Just like wider larger tires on a car allow the larger HP engine to utilize the power, without slipping and wasting the HP, in just spinning teh tires with no grip, more surface area, better traction. Larger drivers with larger coils and magnets more surface area move more air...can't more air without watts and drivers to utilize it. no 5" woofer is gonna move 30Hz air in a room, and sound like teh original instrument, can't happen, no matter what voodo advertising claims

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Quote:
1 - How does the 2000 watts actually increase the power, is there more current available ? are the voltage rails larger ? will it drive a lower impedance ?


Yes to all, everything else being the same.


Quote:
2 - How does the power rating of a speaker get involved, i understand that you have say a 200 watt rating on the voice coils but how is this rating actually affecting things. What are the limiting factors ?


The power rating of a speaker is the manufacturer's determination of the RMS power the speaker "needs" to respond well and the maximum the speaker can be exposed to without being harmed. While one can use a smaller or bigger amplifier than specified, the speaker rating gives one an idea as to what should work best.


Quote:
3 - What I'm getting is if you connect a 200 watt speaker coil to a 2000 watt amplifier we know it will work and not burn out. What is causing this the speaker to only draw enough power that it can handle ? obviously wattage is a function of impedance, voltage and current. So I'm trying to figure out how a more powerful amp on a smaller speaker can work effectively without damaging the voice coil


Two reasons that come to mind. First, the amplifier has an impedance at each frequency that limits the amount of current draw. Second, the 2,000 amplifier is not being driven to its maximum potential; the preamp is limiting the input so that the output is proportionately limited. Thus, the larger amplifier has an output the same as the smaller amp. The only difference occurs when the instantaneous peaks of the music demand more peak power than the smaller amp can provide - then the bigger amp will output more.

One can destroy speakers either by subjecting them to too much current turning them into a big expensive fuse, or to expose them to highly distorted current from a trying to drive them with too small an amp which is being stressed. It's actually easier to do the second.

Welshsox
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Hi

To replay to Jan & Elk's points.

If the speaker rating is not that relevent how can the amplifier power by that critical in blowing up/ fusing a speaker coil ? what limits the energy in a speaker coil ? we know its not the impedance as this is consistantly in the 4-8 ohm range. We know by calculation that watts = (volts x volts) / impedance, therefore if the max watts are fixed and we know the nominal impedance is fixed ( albeit changing with freq ) then a 2000 watt amp must have significantly higher voltage rails than a 100 watt amp.

This then brings me back to the original point, what stops a 2000 watt amplifier from blowing up a 100 watt rayed speaker coil ? I still dont get what is limiting the energy.

Thanks

Alan

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Are you using teh full 420HP in an Audi S4 no, it's limited by what you call for with teh accelerator pedal. Same for a power amp, it's controlled by teh pre amp setting vol control. Do you use teh full flow of the water mains in your street, no, it's controlled by vavles in the system of your house. But when you need more flow, if the system can't supply it, you can't water the lawn, run the shower and run the washing machine at the same time, pressure is voltage analogy flow is the current analogy. The supply needs to have it available when called upon. Otherwise nothing works properly. You ony use it when you call for it right, your kitchen faucet ain't dumping 5 galls/minute everytime you use it, you control it with teh valving in teh faucet. Speakers have the same needs, you control it with teh pre amp controls. If you call for more bass, teh amplifiers better have teh power avaialbe to give teh bass drive, while maintaining teh mid range and highs in full clarity, otehrwise everytime a large bass note comes along teh mids and highs sound like crap, gritty un natural. WATTS, it's important, the speakers take what they need due to their coil impedance and at what freq. their impedance changes beisdes teh coil, the size of the magnet, it's coupling with the cone , so many things, and teh cabinet it's mounted in. Having more than teh required power will always work better, always, it'll handle anything, like having teh power in your car to pull into traffic when everyone is doing 75MPH, and you need to do a high speed merge....it's effortless, when ya got the power to do it, no stress no lag, no strain. Always get the biggest amplifier and the biggest speakers, that's why trucks are made, to carry them to your place.
A 60W incandescent lamp doesn't use teh full current available from the 15A outlet, due to it's resistance which limits what it'll take, speakers are more complex, sicne the lamp filament is just a simple resistance to the line, speakers offer much more to teh power supply. But the power supply (amplifier) needs to be able to handle whatever the load wants. Bigger is better. always always always. Leanred that years ago, using many different combos of amplifiers, most powerful always was better sounding always

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The ratings DO matter, like sizing an air conditoning system for a house, the rating matter, a 5,000 BTU unit ain't gonna work in a full size house. You need more capacity, BIGGER system how do you know the size, ya look at teh RATINGS, that's why they are on it. Jan is really really really .....hmmm the word doesn't come to me at this time....but bizzare? hmmm, we don't need no stinkin' lables or ratings, just get teh size you can carry? Well they also have ratings in dimensions, weight etc. BLOSE sells stuff with no ratings at all, just buy one of them, you can carry it home in one box, problem solved? Nope, cus' you'll miss out on a lot of the sound that's for sure, but you won't have any ratings to worry about boom boom boom no highs no lows, must be BLOSE

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If the speaker's rating is 90db sound pressure for 1 watt then it will depend upon how loud you listen and how much power you dial in (volume control). I thought I remembers that for an 3db increase in loudness you needed 10 times the power. If this is the case 93 db would be 10 watts, and 96 db would be 100 watts before clipping? Dynamic range also falls into this category, maybe, if you are not listening to overly compressed pop music. The issue of how fast your amp reacts to input voltage changes is slew rate, and often sweet sounding tube amps are not as fast, so that is not all the story as to what makes an amp sound great.

90 db and above is pretty loud and I would be more concerned for your hearing at constant levels much above this. I have found most of my serious listening is around 80-85db on average, and often much lower for background listening. More watts does not necessarily sound better. All watts are not equal. Remember watts are heat and it is usually sustained high-powered listening that will bring thermal dissipation issues to drivers over the long haul. Amp clipping can damage drivers as well. That has probably been mentioned already. ST and AD like flea powered SET amps because it is the first few watts that are important, where most of us listen any way. Good luck.

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Quote:
This then brings me back to the original point, what stops a 2000 watt amplifier from blowing up a 100 watt rayed speaker coil ? I still don't get what is limiting the energy.


The preamp. All of the big amp's energy is not available to the speaker because the preamp is limiting the input to the amp. That is, the amp is applying gain only to the input it is provided and the output is thus not the maximum it can provide.

The 2,000 watt RMS rating is simply the maximum RMS wattage the amp can produce. This doesn't mean that it is producing all of this power all of the time.

It is like a high horsepower engine which is limited by the throttle. A Corvette Z06 engine produces a maximum of ~500 HP and lb/ft of torque - but it does this only when told to by one's right foot. It otherwise putts around like any other car.

Welshsox
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Hi

The point im making is that how is the power limited ? then the question of power being limited brings up my next point of why do speakers sound more life like if they have higher input power ?

See the catch 22 in trying to understand, in isoloation its easy to state anything technical but when you combine these things im struggling to understand the whole package.

Bottoem line is what stops a 100 watt voice coil blowing up ona 2000 watt amp ? or is that statement wrong ? does it blow up at full amp output ?

Of course dependent upon the answer given to the question just asked you can then ask what is a high current amplifier doing ? because wattage is also a simple function of volts x amps so if the amps go up then so do the watts.

By the way 3dB increase in SPL is doubling of input voltage.

Alan

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there is dB power, dB voltage etc. acoustic dB...caculated differently, though all based on a non linear scale. double loudness is 3 dB ain't it, and I think it does take 10 times the power to do it. It's so easy to over drive a peanut 100W amplifier. It's real easy to see why more watts is ALWAYS better Unless you listen to background music, then why bother with hi fi anyway? Get a BLOSE and be happy. If you are just worried about teh first few watts, then stick with a clock radio. Hi fi high end is about reproducing the entire performance, which is a lot more than backgroud levels. The mfgs. that use that nonsense in their ads probably produced insufficiently low powered stuff. Pass..... on that first watt idea. Cus the next several hundred/thousand are what is gonna make it REAL.
Low powered amplifiers are like a brownout in teh summer, not enough energy to keep the stuff going properly, lights dim, motors run slow and burn up. When I had a lower power setup, i could pop the 5AMP speaker fuse....more than once, moving on up to more amps, higher powered, still 5 A fuses, NEVER popped, yt i am running higher powered amplifiers, and more of em (4 bi amped) cus' they are each doing less work, less strain, more power always available for the needs when called upon. You'll smoke the drivers faster by over driving an under powered system than you will with power to meet teh demands. When the amp is clipped, it's torture on teh speakers, pooof. Been there done it. these speakers where rated at 93/dB 1 watt input. Having not enough power is just like having a bank account with not enough money in it....you eventually do an overdraft, things go wrong and it's costs money. If you have a large enough bunch of amplifiers like a large enough bank balance things always work better. Always. No such thing as hi fi at 8 watts, you have some amorphous blurr, some muted bloated inarticulate pile of dung. The snap of a snare drum while also proucing the bass guitar line, and foot bass, while teh guitar wails in all it's Les Paul fullness needs lotsa watts, lots. Or it becomes a blur. Fast, un distroted watts, it matters.

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Quote:
The point im making is that how is the power limited ?


You were correct with the formula that "watts = (volts x volts) / impedance" where the voltage is the root mean square (RMS) value of the applied signal. While the impedance of the speaker can go through some wide swings over the audio band, the amplifier is a voltage source delivering a constant voltage (assuming high damping factor) to the speaker regardless of the speaker impedance. The voltage delivered by the amplifier to the speaker is simply the voltage of your source with some gain factor applied by the preamp. Using the hot car analogy (thanks DUP and Elk), the preamp volume control is equivalent to the throttle. You are also correct that the voltage rails of the amp determine the maximum power (assuming constant 8 ohm speaker impedance).

Quote:
then the question of power being limited brings up my next point of why do speakers sound more life like if they have higher input power ?


Live music is usually much louder that what is reproduced in the home. Turning it up sounds more like a live performance (but may annoy the neighbors).


Quote:
Bottoem line is what stops a 100 watt voice coil blowing up ona 2000 watt amp ?


A heavy hand on the volume knob of preamp connected to a 2kW amp could blow damn near any speaker. Of course, at lower levels, this combo could sound just wonderful.


Quote:
Of course dependent upon the answer given to the question just asked you can then ask what is a high current amplifier doing ? because wattage is also a simple function of volts x amps so if the amps go up then so do the watts.


That's right. As I described above, an audio amp is a voltage source and will attempt to drive a constant voltage to the speaker regardless of that speaker's impedance. If the speaker's impedance drops too low, the amplifier power supply may not be able to deliver the required current (remember amps=volts/impedance) causing distortion or clipping. Most amps include a minimum speaker impedance rating.

Quote:
By the way 3dB increase in SPL is doubling of input voltage.


dB=20 log vo/vi which works out to a 6dB gain for doubling the voltage.

Also pertinent to this thread, I found this definition for speaker power rating on the CEA site:

Quote:
the revised standard, CEA-426-B, recommends the maximum power
rating for an amplifier to be connected to the loudspeaker. This could be considered an
"optimum" power match, as this is the most power which can be delivered to the speaker while
permitting the speaker to operate within acceptable limits of performance as defined by CEA in
this standard under the categories of power compression, distortion, and accelerated life
testing.


So if you exceed the "optimum" power match for amplifier/speaker you can expect higher distortion, compression and lower life. The segment of the standard offered for free did not include the particular parameters.

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Hi Welsh,

There are different calaculations when dealing with voltage and power. Doubling the voltage yields 6db more voltage, while doubling the power yields a 3db increase in power. Doubling loudness perceived requires approx 10 times the power.

If one watt gives 90db, 10 watts will be perceived as double the loudness, 100 watts will be perceived as 4 times the loudness.

Power delived to a speaker is determined by the signal voltage applied to the speaker divided by the impedance of the speaker (let's pretend the speaker Z is constant). Cut the signal voltage to the speaker and the current to the speaker will also be cut, thus the power (voltage times current equals power).

The volume control acts like an accelator pedal, as mentioned previously. Lower the volume control and the output voltage delivered to the speaker will also be lower, the speaker current will also be lower, thus the power delivered to the speaker is also lower.

Quality of sound vs power is not standard. By this I mean a larger powered amp may easily sound worse than a smaller powered amplifier. Frequency response may be much worse, though not always, and distortion may also be worse at low power since the pushpull amplifier may have more notch distortion present. If the amplifier is run pure class A, notch distortion should be absent.

Another concern is if the speaker has too low of a minimum impedance for a given amplifier design. For solid state amplifiers, a condition called thermal runaway May be a concern. Tube amplifiers normally don't have this problem unless the total plate dissipation (power input minus output power) becomes too great for the tube (class AB1/AB2/B) in which case the plate may turn cherry, red hot, and arc over.

Hope this helps Welsh.
Steve

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A watt is a unit of HEAT. Amplifiers put out HEAT, not music! A speaker rated at 100 watts is saying it will melt if you heat it up with 150 watts for any period of time.

This speaker should have a transistor amp of about 250 watts running it. The reason you want LOTS of extra power is that it takes very little to jump from 100 to 250 watts when you are playing music.

And if you have a 100 watt amp and it simply can't play the extra power your speaker is asking for the amp will "clip" or distort---and instead of putting out fluctuating amounts of heat it will put out DC non flucuating heat.

This clipped heat doesn't even move the speaker around to cool it off by its own air movement as the speaker moves in and out. Nope---clipped heat just sticks the speaker in one position and turns on the old blowtorch. Goodbye speaker!!!

So don't clip amps---buy BIG ones. And don't crank up your speakers too much (especially if you hear they are straining) or you will MELT them.

That's probably too simple for the experts but it is basically how I would describe the whole deal to a non technical real world user...

And yes I know most tube users say a tube amp soft clips which is true...but you can still apply the same reasoning to tube rigs and their attendant speakers as the same problems still exist to a great extent with tubes too.

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Quote:
If the speaker rating is not that relevent how can the amplifier power by that critical in blowing up/ fusing a speaker coil ?

Amplifier power itself is not critical when you consider how a voice coil can become fused. Given proper program material and played within reasonable limits, a high power amplifier is unlikely to damage a driver. The same could be said for the low powered amplifier. You are looking for absolutes where there are none.

Heat is actually what becomes critical to the survivial of a voice coil. If the voice coil cannot disipate excessive heat, damage will likely occur.

Damaging heat can be the result of either too much clean power applied indiscriminantly or it can be the result of too much dirty power also applied without discretion. Either way heat does the damage.

Since too many people simply ignore the distortion product coming from their systems, too much heat is the most common reason for tweeter failure. However, as has been shown, buying very large amounts of power in order to avoid tweeter damage is an expensive, and often futile, attempt at problem solving. Having more power available than you will ever require is the most appropriate way to resolve the issue and that begins with correct speaker selection.

Either way you go about generating heat - a clipped amplifier or an overdriven voice coil, if the voice coil cannot cool itself quickly and sufficiently, heat builds up and damage is likely to occur. This is a reason for tweeters which employ ferrofluid as a voice coil heat sink to allow for faster heat disipation. Tweeters are the most likely victim of too much distortion which typically results from insufficient speaker sensitivity for the listener's needs.

Woofers are unlikely to be damaged by the distortion component of a clipped amplifier - if for no other reason than you will probably turn down the volume once the tweeters stop working. Also the clipped signal contains mostly upper frequency distortion components which normally would not be allowed in the low frequency driver due to the action of the low pass/high pass filters in the crossover(s). Since low frequency drivers typically have larger and heavier voice coils with larger magnetic gaps and longer throws, along with more heatsink material available to cool the voice coil, they are more likely to be damaged by the heat associated with either high "Q" (sharp attack) or sustained (low "Q") transient material in the signal than by the heat generating distortion of a clipped signal. A long sustained deep bass note will heat up the voice coil of a low frequency driver just as will a series of repeated sharp attacks in the lowest frequencies. Either way unless you change the sensitivity of the speaker you must consider the program material and the heat it generates in the driver's component parts (not the amplifier wattage) as the culprit when a driver fails.

Low frequencies typically require higher electrical power than would mid and upper frequencies to generate the same acoustic wattage within the listening room. With speaker sensitivity fixed, sharp transient attacks (from a drum or electronically synthesized signal for example) demand more amplifier power to accomplish cleanly than the signal of a violin or saxophone with a lower overall "Q" to its attack.

Amplifier power across the frequency bandwidth is not distributed evenly at all points. A single human voice at a 300Hz fundamental will require considerably less power to sustain for a given length of time - at a specific SPL - than would a low frequency (32Hz fundamental) organ pedal note for the same time period and at the same volume level. Therefore, a maximum input power rating which would be correct for a solo voice and guitar will not be adequate when symphonic music is played at an identical peak SPL. Even at similar frequencies a voice coil responding to the sharp, repeated attack of a drum solo will not have the same power handling capacity as a sustained note from a synthesized source. Different amounts of power input result in different amounts of heat for the same SPL. That is what happens when speaker sensitivity remains fixed. Change the speaker's electrical sensitivity and you change how much heat results from each example above when attached to any given amplifier of any wattage rating.

You must understand how the damaging heat is generated before you can begin to understand how the voice coil is actually damaged. The variance in the power required from the amplifier (which is first determined by the sensitivity of the driver/speaker system) and therefore the heat generated in the voice coil(s) is not similar under all conditions. Thus there is no such thing as a 100 watt voice coil. If you don't comprehend that, ask for a recap because that single fact is at the heart of your misunderstanding.


Quote:
This then brings me back to the original point, what stops a 2000 watt amplifier from blowing up a 100 watt rayed speaker coil ? I still dont get what is limiting the energy.

What stops any voice coil from being destroyed by excessive heat build up is common sense. You should now realize there are a few basic and similar factors which play into the act of fusing a voice coil through excessive heat/insufficient cooling. (There are other ways to damage a voice coil but we'll stick with heat damage for now.) When it comes to heat damage there is simply one thing that destroys a voice coil - letting it continue once you hear the situations being set up for damage to occur. There are no 100 watt, 2k watt or 10 watt voice coils. Amplifiers do not play at a constant power output no matter whether they are 100 or 2k watt units. There are situations which can destroy a voice coil when the user ignores the obvious signs of distress.

Heat is not an immediate villain in a voice coil - if there were no heat, there would be no sound (as I assume you've discovered once the voice coil fused and could no longer move). The villain in this scenario is the excessive heat the user allows to build up. If all things remain similar, there is no other excuse for voice coil damage.

Unless you are trying to ask something that I am not understanding, you can forget about impedance and rail voltage and all the other stuff. Speakers blow up when they are abused. You can avoid this situation by changing the level or changing the program material when the voice coil is in danger of excessive heating and insufficient cooling.

If we assume you still want to play the same program material at the same volume, you will have to change the speaker and not the amplifier. Buying a more powerful amplifier when the speaker is in distress from repeated bass drum thwacks at 100dB will not solve the problem. The speaker still maintains the same limits with the same program source. (The case can be made for an amplifier that has more dynamic power and better control at its and the speaker's limits but that is another discussion for another time. Suffice it to say not all amplifiers are created equal.) If the program material is the culprit when it comes to damaging a driver, that limit will apply with virtually any amplifier. Heat will build up in the voice coil due to the electrical resistance of the coil plus the mechanical components of the driver and the system's inability to drain that heat away from the voice coil. This will happen whether you are using a 100 watt or a 2k watt amplifier. You either have to change the program material, the overall volume level or the speaker to avoid this type of damage.

If the heat is generated by a clipped amplifier and tweeters are blowing out, then you will very likely be more sucessful at achieving higher playback levels by changing your speaker than by buying large amounts of power. The amount of volume you can achieve with any speaker is limited to where the speaker starts making sound. If one watt is sufficient to generate 110 dB SPL, at 95dB SPL you have reduced the amount of clipped amplifier heat by a substantial margin over a speaker that can only generate 85dB SPL with that same single watt. Your fist thought should be to the speakers and not to the amplifier.


Quote:
Bottoem line is what stops a 100 watt voice coil blowing up ona 2000 watt amp ? or is that statement wrong ? does it blow up at full amp output ?

The bottom line is you are less likely to damage a voice coil when that voice coil does more with the first watt than what it does with the next 1,999. You are correct in one instance, your statement is wrong. It is you who stops the voice coil from heating to the point where it is damaged and it has little to do with watts or impedance or voltage rails. Buying the right combination of components is where the solution begins.


Quote:
then the question of power being limited brings up my next point of why do speakers sound more life like if they have higher input power ?

There could be multiple reasons why you believe your speakers sound more "lifelike" when they are generating higher SPL's. But your connection in this thread to why a speaker is damaged is stretched to say the least. It may be you are listening too simply and believe only things such as SLAM and ... well, ... more SLAM are important. If that's the case, I would suggest you reconsider what makes music reproduction in your home involving and satisfying. It may be you've made poor decisions regarding your partnered equipment. It might be a case of a pre amplifier with a high output impedance which cannot deliver sufficient voltage/current to a power amplifier with a too low input impedance through too long interconnects. It could be nothing more than a single component which simply doesn't deliver the goods. It's possible you are using speakers which demand a high current amplifier when your existing amplifier does not fill that bill. It may be your system needs a proper set up and your room is the real problem. If you must raise the volume levels to overcome the problems of the room, you are in a self defeating cycle since the room problems only get become evident when the system is cranked higher. There are too many reasons why a system is only satisfying when it is played at high volume levels to single out just one without having more information available. But the most common issues would be, IMO, either poor equipment to start with or poor matching of components and/or room. The exception to that would be someone who simply considers more volume to be more "lifelike". In that case, even respectable components cannot overcome the laws of physics.

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MOSFETS don't run with heat, which is why they are the optimum choice for outputs of quality amplifers. They are also now made better than ever, som eExicons baby, better better better than 30 year ago original Hitachis. It always gets better, cheaper smaller, more efficient. Unless you wanna keep going backwards, and thinking cus' it's old and obsolete it must be better, and sound better. no, it's just old, obsolete. If something old and obsolsete is better why ain't 57 chevys made any more or 66 Mustangs, cus they where horrible cars, simple, new is better. Just like modern amplifiers are much better than some 30-40 year old junk with obsolete componetns and slow stodgy ckts. Some old tube amp from teh 50's is NOT better than modern SS units, nope. New is more efficient, faster ckts, more linear, less distortion, which equate to more accurate REPRODUCTION. If ya wanna CREATE some sound/music, that's why they use old ckts for teh distortion and sound. a Marshall or Fuchs amopp is not made to reproduce hi fi, it's a sound creator, it hs it's own sound applied to the music. A quality hi fi system has no distortion, no sound, only plays what it's givien, nothing added nothing taken away. Not some bloated fuzzy highly distorted tube amp, for reproduction. Nostaglia is not high end hi fi, it's some delusional mind set, that has nothing to do about science of hi fi.

Jan Vigne
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Class T amplifiers run virtually without any heat. High efficiency class C amplifiers run with less heat than low efficiency class A amplifiers. Transistors run with less heat than most tubes. The heat we're discussing is not the result of the type of output device nor the operating class. A hot running class A vacuum tube amplifier needn't result in excessive heat build up in the voice coil of the attached driver. The science of hifi is pretty simple in that regard.

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Jan

The comments on heat do make a lot of sense. It is clear from the thread that numerous understandings of the relationship between SPL, dB, watts, etc exist among the forum viewers.

By discussion though my original question has been answered, its watts ( ie heat ) that cause voice coil damage, not sound energy ( although of course this generates the heat ). This also solve the issue of why you can drive a 10 watt speaker with a 2000 watt amp without causing damage, of course if you over stress the coils they will burn out like any electrical load.

My comment about life like sound was not related to SPL but purely to the fact that most speakers just seem to sound more real with a good power source driving them, any amp that is power limited seems to lose realism.

Alan

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Correct. It is too much HEAT that burns up a speaker voice coil motor. HEAT....WATTS.....SAME THING. However you are incorrect that sound energy GENERATES heat. It is simpler than that...

HEAT generates sound energy! Not the other way round.

What gets audio nuts in trouble is that there are many ways to build a great sounding amplifier. All things being equal you would think people would all ways buy amps with huge amounts of extra watts to prevent their speakers from being fried from a dirty "clipped" DC heat wave.

But the amplifier world has many examples of gorgeous sounding amps that put out say 25 watts and then put out "dirty watts" starting with the 26th watt. And people don't care as long as the first 25 are that pure...

My own formula of how to build a system is to err on the side of muscular clean amplification EVEN IF I GIVE UP A LITTLE BIT OF NIRVANA FROM GOING WITH A LESS THAN SET PURE SOUND... I am sick of blowing up speakers. I want TONS of clean amplification in the final drive stage---TO PROTECT MY PRECIOUS SPEAKERS.

But then again I have beeen blowing up speakers for 50 some odd years... And it gets real tiresome after a while...

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Quote:
But then again I have beeen blowing up speakers for 50 some odd years... And it gets real tiresome after a while...

Then you need to read once again my post concerning heat and how to avoid the problems associated with inefficient cooling. If you continue to blow up speakers, you will do better buying speakers that make more of the first watt than an amplifier that can only produce more heat.

Can you explain how DC components get into a clipped waveform? I can clip my transformer coupled tube amplifiers even though they will not pass DC.

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Can you explain how DC components get into a clipped waveform? I can clip my transformer coupled tube amplifiers even though they will not pass DC.

I have encountered a solid-state amplifier that will momentarily latch at the positive or negative rail voltage when it is clipped. (For the life of me, can't rememember the model.) Fortunately, such amplifiers are very rare.

John Atkinson
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SAS Audio
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I am not sure what brought this response on.

"MOSFETS don't run with heat, which is why they are the optimum choice for outputs of quality amplifers."

What are you talking about? A watt dissapation is a watt dissapation and heat sinks keep the fets themselves cooler, while a tube feels hotter because the lack of surface area a heat sink has. (Wow, an output tube's filament adds a whopping 10 watts) So the efficiency is a few percent less with tubes. Big deal.

"They are also now made better than ever, som eExicons baby, better better better than 30 year ago original Hitachis. It always gets better, cheaper smaller, more efficient."

Class A, AB, And B have efficiency points that are predetermined by physics. Ever hear of a loadline and how to calculte the max power with the least distortion? How about maximum efficiency? Can't change the laws of physics.

As far as sound quality, actually somewhat true as better parts are made today, such as resistors, capacitors, output transformers, and SS devices, etc.

"Unless you wanna keep going backwards, and thinking cus' it's old and obsolete it must be better, and sound better. no, it's just old, obsolete..... Just like modern amplifiers are much better than some 30-40 year old junk with obsolete componetns and slow stodgy ckts. Some old tube amp from teh 50's is NOT better than modern SS units, nope."

Some are better than others in any era. Some old tube stuff blows the doors off of SS and visa versa.

"New is more efficient, faster ckts, more linear, less distortion, which equate to more accurate REPRODUCTION."

Can you prove that? That is quite a statement. So what expertise do you have in the electronics/audio field?

"If ya wanna CREATE some sound/music, that's why they use old ckts for teh distortion and sound. a Marshall or Fuchs amopp is not made to reproduce hi fi, it's a sound creator, it hs it's own sound applied to the music."

So? Music producers want distortion. So what? Tube designs can be designed to produce a particular type of distortion. SS can also be designed to produce the same or more distortion as well DUP. So what is your point?

"A quality hi fi system has no distortion, no sound, only plays what it's givien, nothing added nothing taken away."

Agreed. That is exactly what the goal is for my designs. I think I know what you are coming from DUP. There are some/many who push a certain distorted sound and who do not like live instruments. They have admitted it, even reviewers.

"Not some bloated fuzzy highly distorted tube amp, for reproduction."

Oh really? Sorry but I disagree. I have heard a number of both SS and tube amps, side by side, with the tube amps sounding more real. I also have myself, and friends who can play live instruments and compare to see which sounds more close to the real deal.

Anyway, thanks for the indirect attack on my products DUP, even though you have never heard any of my products.

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Quote:
I have encountered a solid-state amplifier that will momentarily latch at the positive or negative rail voltage when it is clipped. (For the life of me, can't rememember the model.)


My first power amp was the Bose (Blose) 1801. There were no fuses on the output rails or any other speaker protection (I assume to minimize costs). The input op amp voltage supply (+/- 15VDC) was derived from the output power supply rails (+/- 85VDC) by two zener/resistor pairs. One evening during a quiet period after some spirited listening, one of the speakers started howling loudly. By the time I got to the power switch, there was smoke curling up from the amp as well as the speaker. Doing a post-mortem, I found that one of the zeners had failed, killing the op amp and driving the output to the +85V rail. The location on the PCB previously home to the op amp was a black hole. All drivers in the speaker were carbonized. That was the end of my participation as a customer with Bose.

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OMG

Now that you have all rearranged physics

let me ask this of you all

"How does an amplifier get awarded its specification in watts"?

SAS Audio
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"OMG

Now that you have all rearranged physics"

What does this comment mean?? I measure RMS power output with a constant load. Anyone else do it differently? Speakers all vary differently from min to max Z.

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Quote:
I am not sure what brought this response on.

Really?! You can't imagine what brought that response on? I thought you would have been here long enough to know.

Jan Vigne
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Quote:
"How does an amplifier get awarded its specification in watts"?

It brings the teacher an apple? It sucks up to the tech? It bribes an official?

Nah! I go with SAS's answer.

VinnieVeedivicki
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A few of these posts seem to be introducing the concept of how hot the outer case of an amplifier gets by bringing up switching amps and the like which are "cooler to the touch."

I just don't want to confuse our original posting member who was trying to figure out why SPEAKERS get hot and what all this talk about watts means. In his discussion it makes no sense to talk about how warm the amplifier CASE does or does not get...He was asking about what a speaker "sees" as watts and what an amplifier "puts into a speaker as watts." Not whether an amp is this or that "class" and makes its case get this or that temperature.

For our poster's discussion the design of the amplifier class is not the key issue. How many clean watts it plays and WHAT its signal does when it begins to distort are the factors liable to tear up the speaker that is hooked up to it.

Furthermore (addressing Jan's response) I am aware of speaker driver thermal cooling, fluid cooling and other schemes which allow a driver to survive through heat punishment. The size of a speaker voice coil also usually helps guage how many watts of heat a driver can survive... A one inch voice coil can usually survive 100 watts, a two incher 200 watts.

These rough "concepts" begin to give one the parameters of how hard a given set can be driven before disaster takes out the drivers. I maintain that over-building to a certain extent by choosing a tough high SPL speaker and giving it tons of clean power will PROBABLY mean you won't lunch the darn thing... And I am addressing this issue especially to those of us who ask our sets to perform at realistic concert or near concert levels on occasion. You know WHO you are.

Note that to find out how loud a speaker can play (Maximum SPL---Sound Pressure Level in dB) is a VERY useful thing. When I choose a speaker I usually look around for tests and anecdotal stories of how loud it goes... For a given room size you really only NEED a certain loudness or you are playing with stupid loud levels and will damage your hearing. But I all ways want to know WHAT the speaker is reputed to handle (dB wise) before deciding on a purchase.

The good news is that in the last 20 years I have blown exactly ONE speaker. And that was not my fault. Some IDIOTIC producer amped up the volume on a CD with WAAAAAY loud bass and before I could get the volume down---GOODBYE voice coil!!! Makes me want to strangle the morons who keep making CDs LOUDER and LOUDER just because they CAN.

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Quote:
I just don't want to confuse our original posting member who was trying to figure out why SPEAKERS get hot and what all this talk about watts means. In his discussion it makes no sense to talk about how warm the amplifier CASE does or does not get...He was asking about what a speaker "sees" as watts and what an amplifier "puts into a speaker as watts."


Excellent clarification.

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The amplifier's specification is awarded with respect to "NI" or Nominal Impedance.

There are a series of tests to determine this...which is the first one?

SAS Audio
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For newbies, nominal impedance (NI0 he is refering to is normally 4, 8, 16 ohms.

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Quote:
there is dB power, dB voltage etc.

No, db is always a power. It can be calculated using watts, voltage or even current, but it is still always a power.

cyclebrain
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The poor readers of this thread. So much misinformation.

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Not ALWAYS but usually, there is dB v etc check out Wikipedia for it all, mind numbing array of dB stuff usually "power" but not always http://en.wikipedia.org/wiki/Decibel

CECE
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Voltage dB http://www.sengpielaudio.com/calculator-volt.htm

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Figuring voltage changes (more common use than figuring db current changes but the equation is the same) in DB uses a different formula than figuring power changes in DB. Let's not get into power factors etc.

Voltage change in db = 20 X log Eout/Ein
Power change in db = 10 X log power out/power in

Examples:

10 ohm resistor and 20 volt rms constant signal. We drop the voltage to 10 volts rms.

Voltage change expressed in db is -6.
Current change is also halved, so current change in db is -6db.

So both voltage and current halved; from 20 volts to 10 volts, and from 2 amps to 1 amp (because we have 10 volts divided by 10 ohms).

In the above example, the power change expressed in db is approx -6db.

Cheers.
Steve

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power change is still 6 db.

P = (E*E)/R
P1 = (20*20)/10
P1 = 40w

P2 = (10*10)/10
P2 = 10w

db=10 log p1/p2
db=10 log 40/10
db= 6

SAS Audio
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Quote:
power change is still 6 db.

P = (E*E)/R
P1 = (20*20)/10
P1 = 40w

P2 = (10*10)/10
P2 = 10w

db=10 log p1/p2
db=10 log 40/10
db= 6

Thanks for picking that up Cycle. I corrected my above post.

That is what I sometimes do when I am thinking of two things at once. I was thinking db change of 1/2 voltage vs db change for 1/2 power, and then I mistakenly used an example of db change for 1/4 the power. Honest mistake. In my example, 1/2 voltage will yield 1/2 current, thus 1/4 power, so -6db. But halving the power is only -3db change since neither voltage nor current is reduced by 2, but by approx 1.41, thus yielding 1/2 the power.

Hope that is clearer.

Thanks again for catching that Cycle.

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Hey Welsh...You got your answer, right? I am reading this thread and am totally lost as the people that are scientific are discussing how many angels dance on the head of a pin...

You had a couple of germain questions originally: What burns up a voice coil? (too many watts of fluctuating clean current playing music can do it---which if you take averages, those that would exceed the so called maximum wattage the speaker is rated at).

And I tried to point out that a dirty "clipped" watt is nasty looking to a voice coil as it does not even move the darn thing in and out. It just sits there and looks like pure heat to a voice coil and has no forgiveness...

If the clipping in watts exceeds the wattage rating of the speaker and as I say the voice coil is stuck laterally, not moving in and out, it will tear the hell out of the voice coil. Very much like DC current even if not truly DC. (I said this was gonna be sortof non-scientific but hopefully helpful to a newbie. THAT was non scientific but I hope helpful).

A clipped watt is unlike a momentary excessive watt of non-clipped power which has some "wiggle" room because it at least is moving the voice coil in and out and cooling it off a bit... A clipped watt is double dirty as it not only sounds constricted, it inhibits the normal "cooling" that a speaker coil gets from going in and out.

As for why speakers respond so well to having sufficient "headroom" that they can "put out a lot of healthy energy" without sounding strained, that too can be laid at the feet of having enough extra amplification that the leading edge of transients (which ask for a "ton" of power) are not lost but are allowed to breathe. It just "sounds" better to hear the "hot" leading edge in place and not glossed over. And even if it exceeds the rating of the speaker in watts the speaker may just shrug it off because a brief transient doesn't get "hot" enough to cook things...

Look, there are people on this site that are specialists in low power "pure" sounding Hi-Fi. And they are not really the ones to ask about high power (class A/B transistor) concert level high fidelity parameters. Their interests are more about the sonic flavors developed in the petri dish of super low powered more "pure" forms of the art. And I respect that.

I am a meat and potatoes kind of HiFi guy. I just want to kick ass on Hendrix without blowing out drivers. I used to be on the stage and my system is a surrogate for being with the boys again.

All I can hope is that you are getting SOME idea of the breadth of differences that exist in our hobby. All of these guys have some ideas that are priceless. They all want to promote their own particular path to audio nirvana. I learn from them all and I hope you do too.

As for how many angels dance on the head of a pin...well I all ways DID like dancers. They turn me on. Not that you GUYS turn me on. Not that there is anything WRONG with that either... Oh Hell.

Ergonaut
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Wayhay -- Cycle and SAS - well done chaps for posting actual science.

I been hunting about trying to find something worth while to also clear matters up without referencing my damned self all the time.

Try this source...

http://www.lenardaudio.com/education/12_amps.html

CECE
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That page is EXCELLENT. Real information based on real electical design concepts. and it explains the stuff and why it matters or DON'T matter. Just think if more people actually understood what amps and pre amps do, there would be no magic wires and conductive foam lifts. An education is a real mind opening event ain't it? $24K under powered amplifiers would be a hard item to justify to people that understood what an amplifiers is doing. But obsfurcated logic sells magic accessories. Great post, more like that, means less BS.

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Quote:

Wayhay -- Cycle and SAS - well done chaps for posting actual science.

I been hunting about trying to find something worth while to also clear matters up without referencing my damned self all the time.

Try this source...

http://www.lenardaudio.com/education/12_amps.html

Thanks for the link. This was a very informative article, yet I'm still amused that the author took so many potshots at audiophiles and their myths- there was more than a little preachy rhetoric. Shouldn't the scientific truisms speak for themselves? Not that the writer isn't entitled to his opinion.

Also- a refreshing admission that "electromagnetic energy is a mystery."

Then there is the assertion that "not only does excessive dynamic compression remove transients and nuisance from the music..." I assume he meant "nuance" and that his mandate for accuracy doesn't apply to his use of language. I wish it removed the "nuisance."

But his most curious statement is this: "Audiophiles who believe in magical brand names and components not only trivialise electronic technology but show appaling dis-respect for the engineers and scientists who dedicate their lives to the research and development of component and IC engineering." Really? This isn't just a job or vocation? It's a selfless dedication of their being to the cosmic truth of circuitry? This kind of indignation sounds a little self-important, IMO- if not pseudo-religious. But I still think he wrote a great article, despite the proselytizing.

Ergonaut
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Quote:

But his most curious statement is this: "Audiophiles who believe in magical brand names and components not only trivialise electronic technology but show appaling dis-respect for the engineers and scientists who dedicate their lives to the research and development of component and IC engineering." Really? This isn't just a job or vocation? It's a selfless dedication of their being to the cosmic truth of circuitry? This kind of indignation sounds a little self-important, IMO- if not pseudo-religious. But I still think he wrote a great article, despite the proselytizing.

Yeah it does go a bit self indulgent. Though I wouldnt use the word Audiophile for those types of comments ... "Audio-fantasists" perhaps. Audiophiles seem to be normal rational human beings interested in the best possible recreation of musical performances through technology. That doesnt necessarilly mean that they need to know how it works. I just wish that when they do get interested in how it works -- they stick to science rather than fiction.

cyclebrain
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Even though I am a hard core believer in the science of measurements and math, I still believe that there are things that effect sound quality that we don't yet have a way to quantify. But if something doesn't pass the basic fundamentals of science, then lets go no further.

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Quote:
Even though I am a hard core believer in the science of measurements and math, I still believe that there are things that effect sound quality that we don't yet have a way to quantify. But if something doesn't pass the basic fundamentals of science, then lets go no further.

I agree. If it sounds good but measures bad, it's bad. If it sounds bad but measures good, it's still bad. Those aren't my words, I read that somewhere, years ago.

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Quote:
I agree. If it sounds good but measures bad, it's bad. If it sounds bad but measures good, it's still bad.

You have the idea but not the quote.

""If it measures good and sounds bad, -- it is bad. If it sounds good and measures bad, -- you've measured the wrong thing."

http://hhscott.com/vonrecklinghausen.htm

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