too small an amp?
"too small an amp" is nonsense -- a speaker is rated for its thermal power handling -- how much heat it can dissipate when given the rated power -- The speaker does not care whether this is a beautiful perfect sine wave, music, or clipped square waves.
Generally speaking, most manufacturers will test speakers thermally using music as their source due to its low duty cycle, so they can print the higher number on the spec sheet. where as a pure sine/square wave is 100% duty cycle, music is generally not over 20%. Even if you distorted and played music clipped to hell, the duty cycle would not rise much becuase it would not sound good --
as far as why your tweeters are blowing -- ?? -- is the amp of your build? is there alot of dc bias on the output? im sure others have more insight
-chris
"too small an amp" is nonsense -- a speaker is rated for its thermal power handling -- how much heat it can dissipate when given the rated power -- The speaker does not care whether this is a beautiful perfect sine wave, music, or clipped square waves.
Generally speaking, most manufacturers will test speakers thermally using music as their source due to its low duty cycle, so they can print the higher number on the spec sheet. where as a pure sine/square wave is 100% duty cycle, music is generally not over 20%. Even if you distorted and played music clipped to hell, the duty cycle would not rise much becuase it would not sound good --
as far as why your tweeters are blowing -- ?? -- is the amp of your build? is there alot of dc bias on the output? im sure others have more insight
-chris
well I'll tell you exactly what I have the exact crossover circut is the 3.3uf solen. I have two four inch 4ohm mid woofers I don't recall the brand name wired in series running full range and a side mounted 6.5" woofer of the same brand as the mids with a coil crossing it over at approximately 150hz. my amp is a cheap Technics integreated I picked up for $10 at a thrift store and my sources at the time of the blowing were my computer with a sound blaster audigy card and my MCS turntable with an ancient stranton cartridge.
This might seem silly so bear with me but the cap is in series with the tweeter right? And coupled in parallel with the other drivers?
Your current filter is at 9 kHz if my calculations in my head are correct (it's very very late here) and there should be no way in hell your tweeter should blow with that kind of filtering especially considering the Vifa generally are considered very very durable.
If it's not the above then it has to be the amp that is the problem. Try to borrow one from a friend and see if happens again.
Or if you wanna save money, others here might offer you advice in ways to test if your amp is stable enough.
Your current filter is at 9 kHz if my calculations in my head are correct (it's very very late here) and there should be no way in hell your tweeter should blow with that kind of filtering especially considering the Vifa generally are considered very very durable.
If it's not the above then it has to be the amp that is the problem. Try to borrow one from a friend and see if happens again.
Or if you wanna save money, others here might offer you advice in ways to test if your amp is stable enough.
you know I think I just may have realized what the problem is.
Some times I forget to turn the amp off when I plug the cable into the computer and it makes a very loud noise I've already blown two little two inch drivers out that I was using for my computer without crossovers I wonder if that is what was bowing my tweeters. and another thing does anyone know if these tweeter has any replaceable parts or if I would just have to buy new ones
Some times I forget to turn the amp off when I plug the cable into the computer and it makes a very loud noise I've already blown two little two inch drivers out that I was using for my computer without crossovers I wonder if that is what was bowing my tweeters. and another thing does anyone know if these tweeter has any replaceable parts or if I would just have to buy new ones
)
It is true that for those who like music loud and don't mind it
being distorted low power amplifier clipping blows tweeters.
(Because the clipping increases average high frequency power)
3.3uF should be fine as a first order crossover.
Other reasons for blowing are ultrasonic amplifier instability and
dubious sources containing ultrasonic high frequency levels.
If the amplifier ouput devices do not look original then amplifier
instability should be considered. The turntable can be discounted.
Ultrasonics from your computer not so easily.
How do the tweeters go ? charred voice coils or broken wires.
Broken wires = use a second order (or more) crossover.
Charred = too much juice from somewhere.
sreten.
It is true that for those who like music loud and don't mind it
being distorted low power amplifier clipping blows tweeters.
(Because the clipping increases average high frequency power)
3.3uF should be fine as a first order crossover.
Other reasons for blowing are ultrasonic amplifier instability and
dubious sources containing ultrasonic high frequency levels.
If the amplifier ouput devices do not look original then amplifier
instability should be considered. The turntable can be discounted.
Ultrasonics from your computer not so easily.
How do the tweeters go ? charred voice coils or broken wires.
Broken wires = use a second order (or more) crossover.
Charred = too much juice from somewhere.
sreten.
Re: too small an amp?
No, the driver cares for the POWER it receives. A clipping amplifier genearlly would deliver more high frequencies than the non-clipping amp, and so a larger *part* of the power would hit the tweeter. Given that the tweeter can take about a tenth (typically) of the system power there is a danger here, and that is where the idea of the "too small amp" comes from. It should perhaps be "clipping amp" instead.
Brsanko: you say that you have two 4 ohm woofers. Are they connected in parallel? That would load the amp with 2 ohms.
*If* the amplifier goes into oscillation, which it can do if it is broken, modified in some way, or if the load is bad, it can very quickly burn the tweeters. Unless you are driving it to serious distorsion, I'd say that is a probable cause.
A DC bias on the output would not reach the tweeter due to the 3.3 uF cap, though.
zx3chris said:
No, the driver cares for the POWER it receives. A clipping amplifier genearlly would deliver more high frequencies than the non-clipping amp, and so a larger *part* of the power would hit the tweeter. Given that the tweeter can take about a tenth (typically) of the system power there is a danger here, and that is where the idea of the "too small amp" comes from. It should perhaps be "clipping amp" instead.
Brsanko: you say that you have two 4 ohm woofers. Are they connected in parallel? That would load the amp with 2 ohms.
*If* the amplifier goes into oscillation, which it can do if it is broken, modified in some way, or if the load is bad, it can very quickly burn the tweeters. Unless you are driving it to serious distorsion, I'd say that is a probable cause.
A DC bias on the output would not reach the tweeter due to the 3.3 uF cap, though.
Re: Re: too small an amp?
that is exactly what i said -- the power it receives -- it doesnt matter whether it is sine, music, square etc --- and if he chose a 100w tweeter with an amp with 100w output per channel, it was a bad design choice. a fully clipped sine wave will output as a square wave, which has exactly 2x as much power as the sine. this example is not realistic because no one would ever clip to that extreme, but it shows the increase in power -
-chris
Svante said:
that is exactly what i said -- the power it receives -- it doesnt matter whether it is sine, music, square etc --- and if he chose a 100w tweeter with an amp with 100w output per channel, it was a bad design choice. a fully clipped sine wave will output as a square wave, which has exactly 2x as much power as the sine. this example is not realistic because no one would ever clip to that extreme, but it shows the increase in power -
-chris
FWIW, the only tweeters I have ever blown, were DynAudio D28AFs. Which, can handle more power than any tweeter I've owned since. It was a 2nd order crossover around 2Khz. I had run these speakers on numerous receivers without issues. I had a loaner Kenwood (low-end 100W) HT receiver from CC, and blew both tweeters within a few seconds of each other, on the first day of loaner use. Just a little snap-snap noise, and that was it. Both voice coils were open. I don't know if it was just the cheap amp that caused it or a defective one. CC said they retested it and didn't find anything, but not sure how carefully they would have tested it. I have since dropped in PE 1 1/8" silk domes, without a crossover change. My son uses these speakers, at louder levels than I, running off a HK AVR310, with no problems.
Too little amplifier power is the reason 95% of tweeters blow. The other 5% go due to amp malfunction, etc. Back when I was in retail, people would play too loud and pop tweeters repeatedly. They'd come in cussin' and fussin' and bent out of shape because the speakers went in the middle of a party and everybody was bummed out and it was the stupid stereo's fault and blah, blah, blah. After about the third or fourth tweeter, their wallet would start nagging them to pay attention to what I was saying, and I'd sell them a larger amp. Clip the larger amp, and you're going to pop the tweeter that much more quickly, but that's another story.
Power ratings for drivers, whether tweeters, midranges, or woofers, are pretty random. As a general rule, they can take at least two or three times their rated power...as long as the power is clean. Clean means unclipped. At all. Period. Once you start clipping an amp, all bets are off. You can blow a "100W" tweeter with 30W amp if you clip it. Trying to match the amp's rated power to the tweeter's is a nice parlor game, but won't get you anything other than an evening's free entertainment.
The thing that never ceases to amaze me is that people pay absolutely no attention to clipping. They concentrate on the bass, or singing along with the music, or playing air guitar, but rarely on the fact that the tweeter is making little spitting noises.
Oh well, it's their money.
Incidentally, woofers have a different failure mode. Clipping, per se, isn't the problem, it's turning up the bass. Like tweeters, they can take frightening amounts of power, as long as no one jacks up the low end. However, the people who clip amps are generally also the ones who turn up the bass.
Grey
Power ratings for drivers, whether tweeters, midranges, or woofers, are pretty random. As a general rule, they can take at least two or three times their rated power...as long as the power is clean. Clean means unclipped. At all. Period. Once you start clipping an amp, all bets are off. You can blow a "100W" tweeter with 30W amp if you clip it. Trying to match the amp's rated power to the tweeter's is a nice parlor game, but won't get you anything other than an evening's free entertainment.
The thing that never ceases to amaze me is that people pay absolutely no attention to clipping. They concentrate on the bass, or singing along with the music, or playing air guitar, but rarely on the fact that the tweeter is making little spitting noises.
Oh well, it's their money.
Incidentally, woofers have a different failure mode. Clipping, per se, isn't the problem, it's turning up the bass. Like tweeters, they can take frightening amounts of power, as long as no one jacks up the low end. However, the people who clip amps are generally also the ones who turn up the bass.
Grey
brsanko said:
BINGO! That i'll do it every time. You don't have to power off the amp, you can just turn the volume control all the way down. The spike generated by that pop will break the wire connecting the voice coil to the terminal. The other possibility is that the voice coil acts like a fuse. I've seen both. Remember to turn the volune down and you'll be OK.
Later
BZ
A quote "100 watt tweeter" will not take 100 watts, period. It means that it will take the tweeters portion of a 100 watt signal accross the freq band. This is usually less than 10 watts to the tweeter and 90 to the rest of the drivers. As little as one watt of distortion can fry a voicecoil. The energy from a clean signal is translated into sound via movement, a clipped signal is made into heat.
In 1985 - 86
I use to carry 28 piezo tweeters in a Quad Amp Rig, and, kept blowing tweeters.
I was using a Nikko amp (100 watts per channel) at the time. One day, I decided to try a Pioneer Reciever (20 watts per channel) and never lost a tweeter again!
What did I learned from this? Too much power can cause
just as much damage as too little. In my case, 20 watts per channel saved me around 12 tweeters a show.
At $4.00 a tweeter, you can bet I never used 100 watts for tweeters again!
I strongly believe too much clean power can kill a driver faster than a clipped amplifier not producing enough power.
I use to carry 28 piezo tweeters in a Quad Amp Rig, and, kept blowing tweeters.
I was using a Nikko amp (100 watts per channel) at the time. One day, I decided to try a Pioneer Reciever (20 watts per channel) and never lost a tweeter again!
What did I learned from this? Too much power can cause
just as much damage as too little. In my case, 20 watts per channel saved me around 12 tweeters a show.
At $4.00 a tweeter, you can bet I never used 100 watts for tweeters again!
I strongly believe too much clean power can kill a driver faster than a clipped amplifier not producing enough power.
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