Help with Amplifier

[j_garcia]

Dont think so. When a speaker is rated at 125W/RMS 500w/peak that means it will handle 125 W of music content.
He blew the speakers because he clipped the amp, period end of story.

I'm with Mac on this one. Clipping has the potential to destroy speakers in seconds. More than enough power will simply allow you to turn it up to levels that nobody would ever listen at without distortion, up to the point at which the drivers or crossover fail. There's no question in my mind that this is what happened, because I've done it myself with my first stereo, and I've seen others do it many, many times it both home and car audio.

(which the magnitudes required are not possible with a 90 watt amplifier)

Not true. I read an article on clipping that says that what happens is the amp's draw actually spikes up considerably, and even a low power amp can deliver far beyond it's rated power. However, when the amp reaches the point ot saturation where it can no longer deliver the required amount of current to keep the waveform correct, clipping will occur creating the distortion that you hear. That distortion results in the drivers heating up and quite possibly failing. It isn't a guarantee that it will happen in every case, but that IS how it happens. As Mule notes - if you feed a speaker with CLEAN signal, even in excess of the speaker's rating, it is not likely to have an issue. If you feed any speaker with a distorted signal for a length of time, it will eventually fail.

 

[mtrycrafts]

You have obviously not seen his own experimental data where a cheap tweeter handled over 1kW. An 8" eminence mid was even more. And thus, you are WRONG. This was not speculation, but rather fact.

FACT??? Hardly. You don't know all the facts of the case, you jump to premature conclusions.
Yes, it handles a spike for 1 ms. How good is driver that was blown? Is that the one the user blew??? Really? How long was the power applied for? 1ms???
Which driver was blown? You know all these???

 

[jaxvon]

FACT??? Hardly. You don't know all the facts of the case, you jump to premature conclusions.
Yes, it handles a spike for 1 ms. How good is driver that was blown? Is that the one the user blew??? Really? How long was the power applied for? 1ms???
Which driver was blown? You know all these???

1. Cheaper and crappier than a Klipsch reference tweeter.
2.No.
3.Yes, this test really happened. A few milliseconds. But realize that the power the tweeter handled without blowing was more than an order of magnitude higher.
4. The test blew up a tweeter, a horn midrange, and a 15" EV driver. Couldn't blow up the 8" Eminence.

 

[WmAx]

Klipsch has always been known as a great speaker when it comes to abuse. I'm sure there was tons of distortion, but the distortion was from the amp.

I can't see how you can conclude the amp was distorting. 90 watts to a 93db/1 meter/ 1 watt speaker far exceeds normal power requirements for a speaker of that sensitivity. If anything, he simply exceeded the power disappation ability of the tweeter with the average continous signal[afterall, the speaker system might be rated for 100 watts, but a tweeter is typically only really rated for about 10-20 watts]. With certain music, the tweeter can be far more likey to blow due to the spectral distribution being not typical[and tweeters are matched with the system on an average expected spectrum distribution, proporotionately]. The guy was just probably using these speakers at too high of a volume level[compared to what the tweeter can actually handle, which is not reflected in the power rating of the speaker].

-Chris

 

[j_garcia]

Something in the speakers failed, and I'd wager the most likely cause is clipping the amp. It doesn't matter if you have a 105dB efficient speaker in a bathroom if you feed it with a bad signal. We don't know the exact conditions, or what the damage actually was, so it's hard for anyone to say for sure, but based on what we do know, that is my guess.

A buddy of mine fried two tweeters, in two different speakers one time. He had a Denon 4801 driving KEF Q7s and Studio 20s for surrounds. He tossed the remote down somewhere and it hit something and pushed the "+" button in, turning the volume all the way up. He *RAN* over to the receiver and turned it off and hoped for the best, but when I came over to check it out, it was immediately evident that both of the main and surround speakers on the right side had no highs coming from them. Closer inspection showed that both speaker's tweeters had gone bye-bye. We pulled the one from the Studio 20 and it definitely smelled burnt. You could see where the thin voice coil wire had heated up and melted like a light bulb element. The KEF tweeter was not as obvious, but it also smelled burnt and definitely did not work. After replacing both tweeters, both speakers play just fine - no obvious or audible damage to any of the other drivers.

 

[WmAx]

More than enough power will simply allow you to turn it up to levels that nobody would ever listen at without distortion,

90 watts to a 93 db/ 1 watt / 1 meter sensitive speaker is far above any SPL that anyone would listen in a normal music playback application[as opposed to trying to use the speaker for PA system commercially, for example].

Not true. I read an article on clipping that says that what happens is the amp's draw actually spikes up considerably, and even a low power amp can deliver far beyond it's rated power.

Perhaps you should actually refer to Mac's peak power data. You can not get that magnitude of power out of a 90 watt amplilfier. In fact, the peak power output of a SS amp, as defined as an instaneous peak power, is usually in the realm of 2 x the continous rating[I am being generous with this 2x figure]. When an amplifier clips, the voltage quickly loses the ability to increase proportionaly to the input signal, this is the reason the signal is said to be "clipped". As for clipping overheating a voice coil, it's not as straightforward as many would like to believe: and it's unlikely that actual clipping itself has hurt the tweeter[see below], but that an average continous signal is being fed to the tweeter that it was not designed to tolerate[since a tweeter is usually far lower power disappation ability as compared to the other drivers due to the power spectrum of music not requiring a tweeter to hav equal power handling as the other drivers].

If you feed any speaker with a distorted signal for a length of time, it will eventually fail.

Then why do electric guitar speakers seem to work? Afterall, it is typical for a guitarist to use extremely high amounts of distortion. Why don't your speakers fail when you play back heavy metal or hard rock? That is a heavily distorted signal.

-Chris

 

[jaxvon]

Then why do electric guitar speakers seem to work? Afterall, it is typical for a guitarist to use extremely high amounts of distortion. Why don't your speakers fail when you play back heavy metal or hard rock? That is a heavily distorted signal.

Cute, Chirs.

 

[WmAx]

A buddy of mine fried two tweeters, in two different speakers one time. He had a Denon 4801 driving KEF Q7s and Studio 20s for surrounds. He tossed the remote down somewhere and it hit something and pushed the "+" button in, turning the volume all the way up. He *RAN* over to the receiver and turned it off and hoped for the best, but when I came over to check it out, it was immediately evident that both of the main and surround speakers on the right side had no highs coming from them. Closer inspection showed that both speaker's tweeters had gone bye-bye. We pulled the one from the Studio 20 and it definitely smelled burnt.

Of course, the tweeter was probably rated for about 10 - 15 watts. A few seconds of power greatly exceeding that, distorted or not, will overheat the voice coil.

-Chris

 

[j_garcia]

Then why do electric guitar speakers seem to work? Afterall, it is typical for a guitarist to use extremely high amounts of distortion.

They are also generally using amps that are more tailored to that sort of thing, and many guitarists prefer amps that have a particular type of distortion characteristic. The amps can handle the type of distortion they are fed and the speakers can handle the specific type of distortion and because the amps in question can deliver enough juice. This type of distortion is not the same thing as clipping an amp, as I'm sure you are well aware.

Why don't your speakers fail when you play back heavy metal or hard rock? That is a heavily distorted signal.

Because it was recorded that way, and that's the signal that is being amplified, not a clipped signal. The sound may be created by distortion, but the recording isn't a distorted signal, it is just a reproduction of the recorded sound. I should have said clipped signal.

 

[MacManNM]

This is turning into a BS argument too. Look if the guy wants his eardrums to bleed then fine. He needs a bigger amp with PA speakers. He abused his system and grenaded it. Simple as that. It is my opinion that the amp clipped and did it, Chris and Mrty think it was a plethora of other things. The damn thing blew, the guy needs new gear if he wants to go deaf, so buy an amp and some speakers.

Thread Over.

 

[WmAx]

They are also generally using amps that are more tailored to that sort of thing, and many guitarists prefer amps that have a particular type of distortion characteristic. The amps can handle the type of distortion they are fed and the speakers can handle the specific type of distortion and because the amps in question can deliver enough juice. This type of distortion is not the same thing as clipping an amp, as I'm sure you are well aware.

Yes, it is the same as amplifier clipping, as will be found on popular grunge type distortions will are basicly clipping a SS circuit by overdriving it. What do you think is special about a guitar distortion? The differences exist in different types of guitar distortions, as in magnitude of distortion and the specific harmonic orders that are excited at what proportion. But you have the good ol' grunge/fuzz distortions which are the same harmonic structure as a clipping amplifer.

Because it was recorded that way, and that's the signal that is being amplified, not a clipped signal. The sound may be created by distortion, but the recording isn't a distorted signal, it is just a reproduction of the recorded sound. I should have said clipped signal.

It's a clipped signal that was recorded, and the end results is exactly the same... a clipped signal is reproduced and played back.

-Chris

 

[Poshag]

I'm not even sure if you guys are still talking about my SB2s, but from what ive read in this thread, it sounds like clipping was the culprit. It was the drivers that blew on the speakers, not the tweeter. I was havin a party at my place and they had been playing loud as hell for hours, like +5 db volume setting. I was usually around to stop the stupid drunk kids from turning up the volume, but i was preoccupied with a girl, but thats a bullet ill always take

 

[MacManNM]

I'm not even sure if you guys are still talking about my SB2s, but from what ive read in this thread, it sounds like clipping was the culprit. It was the drivers that blew on the speakers, not the tweeter. I was havin a party at my place and they had been playing loud as hell for hours, like +5 db volume setting. I was usually around to stop the stupid drunk kids from turning up the volume, but i was preoccupied with a girl, but thats a bullet ill always take

That will be the story of your entire life. It's her fault! You have a lot of those parties?

 

[Poshag]

yea i have a lot of parties, my place is real close to campus, so people sort of migrate over here alot... My RB-35's are handling the situation alot better (the SB2s are coming back tmrw, gonna put em as rears). And i make sure the volume stays below 0db

 

[MacManNM]

yea i have a lot of parties, my place is real close to campus, so people sort of migrate over here alot... My RB-35's are handling the situation alot better (the SB2s are coming back tmrw, gonna put em as rears). And i make sure the volume stays below 0db

one thing you could do is decrease the output of your cd player so that even if the volume is up all the way it wont hurt anything

 

[j_garcia]

It's a clipped signal that was recorded, and the end results is exactly the same... a clipped signal is reproduced and played back.

It's a distorted signal, but when played back it is not the result of clipping the amp that is driving the speakers, so it doesn't matter that the original sound was generated as a clipped signal. That's why it doesn't cause the same problem that an amp that has run out of power does when trying to drive the speaker.

 

[WmAx]

It's a distorted signal, but when played back it is not the result of clipping the amp that is driving the speakers, so it doesn't matter that the original sound was generated as a clipped signal. That's why it doesn't cause the same problem that an amp that has run out of power does when trying to drive the speaker.

(1). Play a signal that is clipped at X amplitude from amplifier A.

(2). Play a *recording of a the clipped signal from (1) at X amplitude on amplifier B(which is 2x the power of amplifier A so that amplifier B does not clip) so that the peak voltage on both (1) and (2) is the same.

Explain how you would identify (1) and (2) if you were given access to two terminal sets, one being (1) and the other being (2), but the identities were hidden. *Assume the recording has an infinite bandwidth for this excercise.

-Chris

 

[j_garcia]

I'm not questioning whether or not the signal was clipped when creating the sound that was recorded or saying that the waveform that is recorded is different from what was originally created. What I am saying is, when that signal is reproduced on a speaker that is not being driven at the limit of the amp driving it, it isn't creating the same condition at the speaker that a clipped signal being fed to it by an amp that IS clipping does. If you took pink noise and sent it to a speaker within the limits of the amp, then what you get is pink noise. If you turn it up to the point where you clip that amp and distortion is present, then the lack of the amp's ability to deliver sufficient power for the speaker to reproduce the signal is what is actually causing the distortion in the speaker, not the signal itself.

 

[MacManNM]

(1). Play a signal that is clipped at X amplitude from amplifier A.

(2). Play a *recording of a the clipped signal from (1) at X amplitude on amplifier B(which is 2x the power of amplifier A so that amplifier B does not clip) so that the peak voltage on both (1) and (2) is the same.

Explain how you would identify (1) and (2) if you were given access to two terminal sets, one being (1) and the other being (2), but the identities were hidden. *Assume the recording has an infinite bandwidth for this excercise.

-Chris

Ok Chris, you know darn well that when an amp clips its RMS output goes way up. that is the point he is trying to make, I believe.

 

[PENG]

Ok Chris, you know darn well that when an amp clips its RMS output goes way up. that is the point he is trying to make, I believe.

In that case, it is not the clipped waveform that damage the speaker but the way up rms output resulting from amp clipping that does it, right?