I doubt that.
That 100 watt amplifier housed a 7 amp fuse. Fairly high
when other 100 watt amps are anywhere between 2.5 -
5 amps.
I reduced to a 20 watt Receiver with less wattage, and,
amperage is 1.5 amps.
Too much power will kill any driver. You don't have to clip
an amp to burn up a tweeter.
I've seen speakers caught on fire, and, capcitors explode
due to too much power.
That 100 watt amplifier housed a 7 amp fuse. Fairly high
when other 100 watt amps are anywhere between 2.5 -
5 amps.
I reduced to a 20 watt Receiver with less wattage, and,
amperage is 1.5 amps.
Too much power will kill any driver. You don't have to clip
an amp to burn up a tweeter.
I've seen speakers caught on fire, and, capcitors explode
due to too much power.
markp said:
So... What about a distorted electric guitar. Shall I quit listening to Entombed? Seriously, I disagree. Almost all of the power delivered to the voice coil becomes heat. The efficiency of a typical driver is in the 1% range or less. Regardless of the shape of the waveform (clipped or not).
You are right though in that the tweeter only takes about 10% of the system power.
First, I worked at Speaker City in Los Angeles for about 7 years and I can promise you I've seen more blown drivers than you all ever will. I've seen them fail from many different reasons, the most common being distortion due to amp clipping. A musical instruments distortion is not the same a high-fidelity amps clipping so you are comparing two different things so it means nothing in this context. The next most common was broken tinsel leads due to over excursion from too low a crossover freq mostly.Svante said:
AGGEMAM
Lets take a different approach here.
If you have an amplifier that can exceed the Piezo's
voltage won't it kill it?
I'm not sure if you are familiar with pro audio amplifiers,
but they have amplifiers that can power a 100 watt
light bulb easy.
In other words slew rates anywhere from 50 - 120 volts
continuous.
When Speakers go up in flames, I'm not going to say,
thats not suppose to happen because in theory you
can't kill speakers with too much power.
I believe in real world conditions.
Please keep in mind I'm reffering to Pro Audio which
is a totaly different ball game from home audio.
Yes. I used an 8 ohm Resistor at the time. Crossed
over at around 5Khz (If memory serves me correct)
with the electronic crossover.
Actually, the only way to save them from dieing on
the 100 watt amp, was to run them series parallel.
Lets take a different approach here.
If you have an amplifier that can exceed the Piezo's
voltage won't it kill it?
I'm not sure if you are familiar with pro audio amplifiers,
but they have amplifiers that can power a 100 watt
light bulb easy.
In other words slew rates anywhere from 50 - 120 volts
continuous.
When Speakers go up in flames, I'm not going to say,
thats not suppose to happen because in theory you
can't kill speakers with too much power.
I believe in real world conditions.
Please keep in mind I'm reffering to Pro Audio which
is a totaly different ball game from home audio.
Yes. I used an 8 ohm Resistor at the time. Crossed
over at around 5Khz (If memory serves me correct)
with the electronic crossover.
Actually, the only way to save them from dieing on
the 100 watt amp, was to run them series parallel.
I repair 5-10 HF drivers every day. 90% of the time, the failure is due to amplifier clipping. This creates a disproportionate amout of power to be sent to the HF driver, and usually causes the VC to cook, or the lead wire(s) to melt. When I explain to my customers why they are blowing their HF drivers and tell them to turn their power amps up and run the signal clean, they usually don't have any problems anymore. I deal with everyone from the basic garage band, to the touring professional, to the studio engineer, to the home HiFi enthusiast. This usually solves the problem in all of these applications. Keep in mind...... It's not always the amplifier that's clipping. Often, the signal being fed to the amplifier is dirty from the source or the mixer. This happens quite a lot with DJ's that aren't familiar with their equipment. When they run the signal pegged in the red, the amplifier is being fed horribly clipped signals, and can cause the same damage as amplifier clipping.
The biggest trick is to try and match the amplifier power with the speaker's rated capacity. This isn't always accurate (it usually isn't) but it is a good place to start. If running a separate power amp, turn it all the way up and controll the volume with the pre-amp. If using a receiver, just listen for distortion. When the music starts sounding ugly and grating, turn the damn thing down.
Cheers,
Zach
The biggest trick is to try and match the amplifier power with the speaker's rated capacity. This isn't always accurate (it usually isn't) but it is a good place to start. If running a separate power amp, turn it all the way up and controll the volume with the pre-amp. If using a receiver, just listen for distortion. When the music starts sounding ugly and grating, turn the damn thing down.
Cheers,
Zach
OMNIFEX said:
Yes, you could try actually reading my post
OMNIFEX said:
Yes, and that was exactly what I wrote.
OMNIFEX said:
Excately why noone actually uses peizos in good pro gear because they blow up at more than 50 volts usually.
OMNIFEX said:
Or you could try running them in parallel only which improves the voltage handling.
Remember that piezo are capacitive loads not resistive, and behaves directly opposite of those.
You are probably right about that.markp said:
But how do you know the reson? Are you there together with your customers as they blow the tweeters?markp said:
Well, that was half a joke. You are right it is not the same, but the two has thing in common. The entombed style music would have a high *average* power, and a lot of HF content, rightmarkp said:
I think we agree on this:
-Tweeters have far less power handling capacity than the maximum *system* power.
-Amplifier clipping shifts the spectral density towards higher frequencies.
-Running an amplifier into clipping makes the amplifier deliver more average power, since the level variation over time of the music is lost.
I think it is these three points in combination is what burns tweeters.
I think we possibly disagree on this:
-It is the *power* that is delivered to the tweeter that burns it. The shape of the waveform (at the tweeter terminals) makes very little difference.
Right?
Svante said:Well, that was half a joke. You are right it is not the same, but the two has thing in common. The entombed style music would have a high *average* power, and a lot of HF content, right
Nope! The distortion from a guitar is anything but HF. In fact most guitar caps don't produce sound over 5-8 KHz, and it's the output of the guitar cap that is mixed into the music and afterward tonitically balanced.
AGGEMAM said:
Hmm. By "cap" you mean the pickup coils on the guitar? If so, what about after it has gone through the distorsion box? I do admit that the frequency content is probably more limited in the (distorted) guitar signal than a clipped lofi amp, but you must admit that the effects of the guitar distortion box and the clipped amp are at least similar?
Svante said:
By guitar cap, I mean the guitar amplifier cabinet, you know the ones from Mashall, Fender, MesaBoogie, etc. Which have an amplifier and speakers built into one unit.
The output of those is always (with rock music anyways) run into a microphone placed in front of it. And the signal from that microphone is then mixed with the rest of the music.
The signal from a guitar is never taken directly from the guitar. This is because the guitar cap is just as important part of the actual sound of the guitar as the guitar itself and the different effect pedals used.
The series resistor is there to protect the amp from the tweeter in the first place (load stability). Oscillation due to the capacitive load may in turn kill the piezo.
But it should be possible to protect the piezo against overload by some kind of voltage limiter (like zeners or even a more refined principle) that is connected accross the piezo after the resistor. There are even piezos available with built-in protection.
And it is never a bad idea to keep low frequencies away from them since it reduces distortion and increases power handling.
Although they are not the best tweeters around, they are quite good value for the money. But most users do not get the maximum performance they could deliver.
Regards
Charles
But it should be possible to protect the piezo against overload by some kind of voltage limiter (like zeners or even a more refined principle) that is connected accross the piezo after the resistor. There are even piezos available with built-in protection.
And it is never a bad idea to keep low frequencies away from them since it reduces distortion and increases power handling.
Although they are not the best tweeters around, they are quite good value for the money. But most users do not get the maximum performance they could deliver.
Regards
Charles
AGGEMAM said:
Ok, I see, and agree. And a amp-speaker-mic chain would probably attenuate the highest frequencies a lot. And probably that is the most common way to record a (distorted) guitar. Still, there are differences in tweeter-blowing capacity between musical genres. Just for the fun of it, I recorded some long-time average spectra for some mp3's I happened to have on my computer:
http://www.tolvan.com/LTAS-Madonna.gif
http://www.tolvan.com/LTAS-Queen.gif
http://www.tolvan.com/LTAS-Entombed.gif
http://www.tolvan.com/LTAS-Thastrom.gif
http://www.tolvan.com/LTAS-Square.gif
I'd say that Thåström is as bad for the tweeter as the square wave. (It has a severely distorted "singing" voice, not nice).
Svante said:
Actually, I'd say it's bad for the ears, but that's another ball game.
(And if you want something that is really bad, so bad in fact that I find it good, go for Onkel Kånkel instead)Also note that MP3's filter away frequencies above 12-16 KHz dependending on bit rate and as such is relatively tweeter friendly.
reply
Well simple protection to protect tweeters.
PTC resistor wired parrallel with tweeter and miniture lightbulb wired in series with tweeter.
PTC draws current,and to avoid drop in current tungsten bulb lights up.
In extreme cases the light bulb blows which saves the tweeter from burn out.
The powerline piezo tweeters[handles 400w rms each] use this protection circuit and so do the Eminence crossovers.
85 per cent of tweeters are blown by clipping.
5 per cent of tweeters blown by dropped mic/mic extreme feedback[squeal sound]
5 per cent of tweeters blown by excessive EQing
4 per cent of tweeters blown by too much power
1 per cent of tweeters blown by manufacting defect in vc.
The above circuit protects against all the above,worse can happen is blown bulb not tweeter.
And as for speakers going up in flames,lol never seen that happen,worst was speaker with smoke pouring out of the spider area[ an old and cheap 10 inch guitar speaker] which i played too loud and with too much bass put into it.And an awful burning rubber smell.And after that cone/vc was totally stuck in gap[wouldn't move a mm by hand and no sound].
Well simple protection to protect tweeters.
PTC resistor wired parrallel with tweeter and miniture lightbulb wired in series with tweeter.
PTC draws current,and to avoid drop in current tungsten bulb lights up.
In extreme cases the light bulb blows which saves the tweeter from burn out.
The powerline piezo tweeters[handles 400w rms each] use this protection circuit and so do the Eminence crossovers.
85 per cent of tweeters are blown by clipping.
5 per cent of tweeters blown by dropped mic/mic extreme feedback[squeal sound]
5 per cent of tweeters blown by excessive EQing
4 per cent of tweeters blown by too much power
1 per cent of tweeters blown by manufacting defect in vc.
The above circuit protects against all the above,worse can happen is blown bulb not tweeter.
And as for speakers going up in flames,lol never seen that happen,worst was speaker with smoke pouring out of the spider area[ an old and cheap 10 inch guitar speaker] which i played too loud and with too much bass put into it.And an awful burning rubber smell.And after that cone/vc was totally stuck in gap[wouldn't move a mm by hand and no sound].
been there done that
Having blown a lot of tweeters in my time (and a few mids as well), I thought I'd just show this post that I made in the solid state forum http://www.diyaudio.com/forums/showthread.php?postid=248708#post248708
Ignore my ramblings about rail votage the important bit is bluetak
In the end I invested in some polyswitches, and never blew any more tweeters, but that is another story.....
Amp is 100W/channel.
Regards,
Tony.
Having blown a lot of tweeters in my time (and a few mids as well), I thought I'd just show this post that I made in the solid state forum http://www.diyaudio.com/forums/showthread.php?postid=248708#post248708
Ignore my ramblings about rail votage the important bit is bluetak
In the end I invested in some polyswitches, and never blew any more tweeters, but that is another story.....
Amp is 100W/channel.
Regards,
Tony.
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