Well it will be more than slightly dependent on more than that.
While generally true won't a bigger tweeter ( 32mm voice coil ) handle more power and a smaller voice coil ( 20mm ) handle less? What about those older cone tweeters with tiny voice coils and magnets ( 8-12mm )
So you can't actually say anything about power handling as a generalisation, everything is dependent on too many variables, such as VC material, winding insulation and the use of ferrofluid and heat sinks.
I would hazard a guess that the 5watt rating from SEAS would be for continuous power on a 25mm VC tweeter but the same tweeter MAY be able to handle a transient of much greater power as the duration is short.
While generally true won't a bigger tweeter ( 32mm voice coil ) handle more power and a smaller voice coil ( 20mm ) handle less? What about those older cone tweeters with tiny voice coils and magnets ( 8-12mm )
So you can't actually say anything about power handling as a generalisation, everything is dependent on too many variables, such as VC material, winding insulation and the use of ferrofluid and heat sinks.
I would hazard a guess that the 5watt rating from SEAS would be for continuous power on a 25mm VC tweeter but the same tweeter MAY be able to handle a transient of much greater power as the duration is short.
A tweeter can probably handle 400W just fine for real music. I had a 400W pro amp that is used by some theatres, and one day while playing really loud at a party (which stopped when the police arrived), the amp overheated and went into thermal protection, while the tweeter (a Dayton Reference 28mm tweeter) was just fine.
One other thing, in a proper crossover the woofer is going to run out of steam before the tweeter does.
One other thing, in a proper crossover the woofer is going to run out of steam before the tweeter does.
WITH a properly designed XO?? This discussion needs clarification as it seems a lot of people need to understand the very real difference between "System power" and the actual power rating of the unprotected tweeter.
Hi,
White noise is constant energy per Hz so 10KHz to 20KHz contains
as much energy as 0Hz to 10KHz and nothing to do with music at all.
Pink noise (constant energy per octave / unit logf) is used for testing.
Music is not pink noise either but its far closer to pink noise than white.
Pink noise tilted to be +9dB at 20Hz and -9dB at 20KHz is reasonable.
RMS Watts power handling of tweeters is completely near meaningless.
rgds, Sreten.
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Following along with Stig..
This type of tweeter is almost always less than 1% power efficient so you can be assured that 99% of the power driven into it becomes heat.
So for exercise I'll apply 5 watts DC to an old D26TG-35 and see how hot it gets. I expect it to get startlingly warm compared to any time in the last 20 years, including when it played music.
I don't expect it to survive 10 watts continuous, but we'll see..
This type of tweeter is almost always less than 1% power efficient so you can be assured that 99% of the power driven into it becomes heat.
So for exercise I'll apply 5 watts DC to an old D26TG-35 and see how hot it gets. I expect it to get startlingly warm compared to any time in the last 20 years, including when it played music.
I don't expect it to survive 10 watts continuous, but we'll see..
At 5.5 volts into the 6 ohm coil, after 30 seconds I got that smell you never want to smell when playing your system. The coil held for 1 hour at 5 watts and the magnet structure went up to maybe 45C in a 20C room, sitting on concrete. I raised the drive to 8 volts, for about 10 watts, and got visible smoke and an open coil in 10 seconds.
End result, I'd say you never want to feed such a tweeter more than 2 watts average, long term.
There, now I have a good reason to throw away that tweeter.
End result, I'd say you never want to feed such a tweeter more than 2 watts average, long term.
There, now I have a good reason to throw away that tweeter.
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Wow, I didn't expect anyone to go to such lengths to answer this question but thanks anyway. I had a good laugh but you didn't have to destroy your speaker. Adrian.
Thank you very much, Andrew, for your great contribution. I am happy to know I was spot on with the 10W figure, but did not realize that 5W was already enough to damage the tweeter.
I've always wanted to test human hearing up to 40kHz, but it would require a tweeter that can output 150+ dB at 40kHz for a human to hear. So I may never be able to perform such a test.
I've always wanted to test human hearing up to 40kHz, but it would require a tweeter that can output 150+ dB at 40kHz for a human to hear. So I may never be able to perform such a test.
It's the thin wire that they wind the voice coil with. A rule of thumb for a 12 db passive 3-way crossover is the power is distributed 60-25-15 %. Tweeters are the most common item to blow whether it's in a car or a hi-fi.The problem is when you run a low power amp at high levels and it starts clipping. So as they say: low power amplifiers blow tweeters and high power ones rattle woofers.
Mac
Mac
Power Handling -
No matter how efficiently a voice-coil tweeter is coupled to the air, current flowing in the voice coil resistance will create heating - it is simple I-squared x R loss and is inescapable. Ferrofluid-type tweeters raise the loss-handing ability of the tweeter by passing some heat through a fluid. If you feel a 7 watt night light some time, you will get an idea of what 7 watts can do in terms of heating. The cooling surface of the night light is probably much greater than of the voice coil.
You may estimate the voice coil heating power by first measuring the resistance of the voice coil and then measure the rms AC voltage on the voice coil when music is present. Heating Power = Vrms squared / R of coil.
Another method is to use an accurate ohmmeter to measure the voice coil resistance. Copper has a well-known tempco of resistance. Connect an ohmmeter to the voice coil and then play some typical music. Now shut the music off and quickly observe the voice coil resistance. The increase in resistance may be used to compute the voice coil temperature for normal operation with that music program at that volume. Contact the tweeter manufacturer to obtain the maximum voice coil temperature for that tweeter.
Piezo tweeters are quite different. The most important parameter of the piezo tweeter for reliability is the breakdown voltage. If the voltage across the piezo element is large enough to cause breakdown, then large currents may flow from the power amplifier through the piezo element, resulting in sudden heating. If the piezo gets hot enough, it may depolarize, which is similar to a voice-coil tweeter magnet losing its' magnetic field. Hotter still and the piezo element will fry and will be ruined. The breakdown voltage is temperature sensitive, and becomes lower as the piezo element heats in normal operation. I have seen BV as low as 7 volts for junk tweeters.
A simple safety circuit for the piezo tweeter is a back-to-back zener diode across the tweeter terminals. The zener breakdown voltage must be lower than the lowest breakdown voltage of the tweeter in normal operation. Now however, the zener itself is at risk of damage from the amplifier, so insert a 50-ohm resistor in series with the amplifier drive wire to protect the zener diodes from being overdriven.
Do not bother looking for the breakdown voltage of a piezo tweeter on the internet. You will have to rig up a test circuit to measure it yourself. Just be sure the test current flowing into the tweeter is limited to about 1 milliamp.
No matter how efficiently a voice-coil tweeter is coupled to the air, current flowing in the voice coil resistance will create heating - it is simple I-squared x R loss and is inescapable. Ferrofluid-type tweeters raise the loss-handing ability of the tweeter by passing some heat through a fluid. If you feel a 7 watt night light some time, you will get an idea of what 7 watts can do in terms of heating. The cooling surface of the night light is probably much greater than of the voice coil.
You may estimate the voice coil heating power by first measuring the resistance of the voice coil and then measure the rms AC voltage on the voice coil when music is present. Heating Power = Vrms squared / R of coil.
Another method is to use an accurate ohmmeter to measure the voice coil resistance. Copper has a well-known tempco of resistance. Connect an ohmmeter to the voice coil and then play some typical music. Now shut the music off and quickly observe the voice coil resistance. The increase in resistance may be used to compute the voice coil temperature for normal operation with that music program at that volume. Contact the tweeter manufacturer to obtain the maximum voice coil temperature for that tweeter.
Piezo tweeters are quite different. The most important parameter of the piezo tweeter for reliability is the breakdown voltage. If the voltage across the piezo element is large enough to cause breakdown, then large currents may flow from the power amplifier through the piezo element, resulting in sudden heating. If the piezo gets hot enough, it may depolarize, which is similar to a voice-coil tweeter magnet losing its' magnetic field. Hotter still and the piezo element will fry and will be ruined. The breakdown voltage is temperature sensitive, and becomes lower as the piezo element heats in normal operation. I have seen BV as low as 7 volts for junk tweeters.
A simple safety circuit for the piezo tweeter is a back-to-back zener diode across the tweeter terminals. The zener breakdown voltage must be lower than the lowest breakdown voltage of the tweeter in normal operation. Now however, the zener itself is at risk of damage from the amplifier, so insert a 50-ohm resistor in series with the amplifier drive wire to protect the zener diodes from being overdriven.
Do not bother looking for the breakdown voltage of a piezo tweeter on the internet. You will have to rig up a test circuit to measure it yourself. Just be sure the test current flowing into the tweeter is limited to about 1 milliamp.
Thanks for that! I was about to do a similar test, but my little tweeter gets to live another day.
Is there a chart showing actual power handling capability vs. the figures that the marketing guys put out? I mean, a tiny tweeter rated at 50W RMS? Please! Have you seen a 50W wirewound resistor?
As balerit mentioned above, in a 100W 3 way speaker system the power distribution would be woofer 60W, mid-range 25W and tweeter 15W. Is that what the marketing guys mean? That would make a tweeter marked 50W actually rated for 7.5W, but even that seems like wishful thinking.
Andrew Eckhardt - that was over and beyond the call of duty. Respect! My tweeters thank you.
As balerit mentioned above, in a 100W 3 way speaker system the power distribution would be woofer 60W, mid-range 25W and tweeter 15W. Is that what the marketing guys mean? That would make a tweeter marked 50W actually rated for 7.5W, but even that seems like wishful thinking.
Andrew Eckhardt - that was over and beyond the call of duty. Respect! My tweeters thank you.
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I've done some tests on a high quality SEAS tweeter with ferro-fluid and with a high-pass filter in place. I used music as a test signal. The tweeter took 4 Watt RMS for about two ours without any sign of trouble. The average temperature of the voice-coil increased to a little above 30 degrees Celsius and during short very loud fragments (perhaps not surprisingly, drum cymbals appeared to contain a lot of high frequency energy) the temperature increased to a little above 40 degrees. The more interesting fact is that the amplifier occasionally clipped at 70 Volt, which corresponds with about 800 Watt into a 6 ohm load! At some point in the future I'll probably repeat the test with a bigger amp and I'll try to actually blow up the tweeter in a controlled way.
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