Well, that's the point you don't seem to get.
Sorry, I don't wand to sound rough or unkind, not my style.
Absolutely not. No way.
1) The waveform we are analyzing is *still* a 100Hz one, be it square, sine or whatever.
The 20KHz component you mention will be that one given by the Math posted above, there's no other, unless you invent a new Physics, Math, or both.
2) To analyze it from another point of view (which confirms my earlier statements, the beauty of Science is that it's consistent):
* Suppose the 100Hz squarewave has a leading edge which rises within 50uSec.
* Suppose it reaches 40 V.
(as you see I am so sure about what really happens that I accept all your premises)
* Peak power will be 40*40/8=200W (you must be smiling by now
)*BUT* that narrow pulse will repeat every 10000uSec (we *still* have those pesky 100Hz as base frequency
)Duty cycle will be: 10000/50=200 .
So average power dissipated by that poor voice coil will amount to 200W/200=1W.
Piece of cake.
3) To see it from a *third* point of view:
The "leading edge" of the 100Hz squarewave will reach 40V.
Fine.
But a component will be a sinewave
Which the "leading edge" is not, by definition.
The "20 KHz component" will be a sinewave (at least, that's what Fourier says).
Its amplitude will be given by the formula posted above.
Yes, this last point confirms point (1) .
Why does it not surprise me?
input a 1kHz sine-wave and set the level to be just below clipping.
Attach a passive crossover set to 3kHz.
Measure the signal at the treble driver. It will not be zero.
The crossover attenuates the signal, it does not eliminate the 1kHz.
Now change the signal to 1kHz square wave.
The amplifier will be delivering almost double the power.
All of the extra power is due to the harmonics of the 1kHz fundamental. The first harmonic of the square wave series is the third, @ 3kHz.
Just measure the signal at the treble driver. That measured 3rd and higher is virtually unattenuated by the crossover.
You will find that the power being delivered to the treble driver will have increased to nearly the same as the amplifier was delivering when the unclipped signal was being passed.
The Treble power will have increased at least one hundred fold. (+1000%)
Ordinary clipping of music signals does something approaching "square waving" of the signal.
The extra energy in the clipped signal is not due to higher maximum voltages but due to increased content of harmonics. Instead of 0.1% of harmonic distortion, one is getting 20%, or 50%, or in the extreme case 100% of added harmonics.
The passive crossover ensures that much of the harmonics are delivered to the treble and mid drivers.
Clipping destroys treble drivers.
Attach a passive crossover set to 3kHz.
Measure the signal at the treble driver. It will not be zero.
The crossover attenuates the signal, it does not eliminate the 1kHz.
Now change the signal to 1kHz square wave.
The amplifier will be delivering almost double the power.
All of the extra power is due to the harmonics of the 1kHz fundamental. The first harmonic of the square wave series is the third, @ 3kHz.
Just measure the signal at the treble driver. That measured 3rd and higher is virtually unattenuated by the crossover.
You will find that the power being delivered to the treble driver will have increased to nearly the same as the amplifier was delivering when the unclipped signal was being passed.
The Treble power will have increased at least one hundred fold. (+1000%)
Ordinary clipping of music signals does something approaching "square waving" of the signal.
The extra energy in the clipped signal is not due to higher maximum voltages but due to increased content of harmonics. Instead of 0.1% of harmonic distortion, one is getting 20%, or 50%, or in the extreme case 100% of added harmonics.
The passive crossover ensures that much of the harmonics are delivered to the treble and mid drivers.
Clipping destroys treble drivers.
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"he passive crossover ensures that much of the harmonics are delivered to the treble and mid drivers."
And the clipping is largely at the lower frequencies and the harmonics feeding the tweeter are trivial (assuming a good crossover).
"Clipping destroys treble drivers. "
You still have not proved this, and direct examination of failures does not show damage from excess long-term average-power.
The primary failure mode seen on most tweeters is mechanical failure of single-strand lead-out wires. In other words, they don't burn up, they break.
Cone motion increases at a 12dB/oct rate as the frequency goes down. Program material can increase at a 6dB/oct rate going down to about 250hz or so. Unless the tweeter has an 18dB/oct crossover the lead-out wire can fracture. Most speakers having problems had either a 6dB or 12dB crossover, and a single-strand lead-out wire. I was astonished the first time I put a spectrum analyzer on a tweeter after repair. Playing program material it looked like the crossover was around 500hz, not the 4.5Khz it showed with pink noise. This was a 6dB crossover, and the single-strand lead-out wire tweeters dropped dead on a regular basis.
And the clipping is largely at the lower frequencies and the harmonics feeding the tweeter are trivial (assuming a good crossover).
"Clipping destroys treble drivers. "
You still have not proved this, and direct examination of failures does not show damage from excess long-term average-power.
The primary failure mode seen on most tweeters is mechanical failure of single-strand lead-out wires. In other words, they don't burn up, they break.
Cone motion increases at a 12dB/oct rate as the frequency goes down. Program material can increase at a 6dB/oct rate going down to about 250hz or so. Unless the tweeter has an 18dB/oct crossover the lead-out wire can fracture. Most speakers having problems had either a 6dB or 12dB crossover, and a single-strand lead-out wire. I was astonished the first time I put a spectrum analyzer on a tweeter after repair. Playing program material it looked like the crossover was around 500hz, not the 4.5Khz it showed with pink noise. This was a 6dB crossover, and the single-strand lead-out wire tweeters dropped dead on a regular basis.
X2 and X2 again.
Technically YES. Perceptionally DUBIOUS.
This is like the argument that comes up almost weekly - is 10W enough. Enough for WHAT ??
When I was building my first Class A it was supposed to be 40W at Class A. Was it loud enough ? Most of the time it was absolutely deafening but occasionally I wanted to drive it at high volume. It was then that the limitations of the design became apparent and the ceiling left a lot to be desired. Most of the time though it was being operated at less than 5W and it was fine. I've now got a 100W Class A and the perfermance is outstanding.
Big 1000W amplifiers are rarely used in household situations and will (nearly always) have the headroom that is required for them to operate linearly at high volume.
In club and stage situations Hi-Fi performance is often compromised but if 1000W Main Amps are being used then Sub-Sonic amps will need to be substantial in order to keep up with them.
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With a single pole high pass, you will actually get roughly equal voltages from each of the squarewave's harmonics below the pole's frequency, all the way down to the fundamental. The rise in level as you go down the harmonics is pretty much exactly matched by the filter's increasing attenuation.
Luckily crossovers tend to be at least double pole.
Luckily crossovers tend to be at least double pole.
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Not the ones found in cheap speakers. I've seen too many "3 ways" with a toy midrange and tweeter, and just a cap and an L pad on each. This kind of speaker is much more subject to abuse than something somebody spent $2000 on. I've seen just as many failed level controls as tweeters. Luckily, they are cheap to replace, but are doomed to repeak failure without putting in a 'real' crossover. Unfortunately, putting in a stock 3-way 12dB usually sounds worse than the original two capacitor "crossover" until you spend time, effort, and money to optimize it.
10% THD is barely perceptible... try it for yourself. At 5% THD, you won't even pass the blind test.
10% THD would be 20dB down.
"This is BS, I clearly notice about 1dB steps if not less. "
Depends on the circumstances.
I made a stepper attenuator for an HF driver that went in 1/4dB steps. While the effect was clearly audible, no one could say if I had raised or lowered the HF by 1/4dB, though all would say that the sound had "gone out of focus" with the change.
"This is BS, I clearly notice about 1dB steps if not less. "
Depends on the circumstances.
I made a stepper attenuator for an HF driver that went in 1/4dB steps. While the effect was clearly audible, no one could say if I had raised or lowered the HF by 1/4dB, though all would say that the sound had "gone out of focus" with the change.
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I did the THD test on the Klippel site with my speakers and could fairly easily hear -45dB THD (0.5%).
An analog synth, or even using an oscillator set to, say, 6KHz sinewave and then driving the amplifier to clipping , simply is NOT a realistic test signal , it can't be used as "proof" as to what a Music program , (*any* music program by the way, from Classic to Punk to Death Metal) can do when overdriving a Power Amp connected to a multiway Speaker cabinet, which is the point of this discussion.
OF COURSE, if you drive a tweeter coil with 100W RMS sinewave (clipped or not) at a frequency which passes easily through the crossover, it will burn the VC before mechanical stress breaks the wire.
So what?
Not what we are discussing here.
OF COURSE, if you drive a tweeter coil with 100W RMS sinewave (clipped or not) at a frequency which passes easily through the crossover, it will burn the VC before mechanical stress breaks the wire.
So what?
Not what we are discussing here.
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