First blown bass speaker

[Old Garage-Bander]

I killed one of those 50w 4 ohm Aura Pro shakers once... actually smoked it. Bad combination of math and "can't hear how loud it is". After I found my math errors I realized that I had potentially 700w available. And it was feeling awesome right up until it smoked.

Must have been magnificent? I hope you recorded it for use in a synth?

Oh there you go with that math stuff. Used to tick me off always wondering when I'd ever need to use the math.
Oh yeah! So I didn't have to do the math on how a new speaker would drain my wallet.

 

[swarfrat]

It was a shaker - though you could hear it faintly. But ... oh man... It might not make much sense but I found it helped a ton with bass in headphones and especially fretless intonation. I don't know that it had enough bandwidth for pitch, so I'm guessing it helps you feel the tiniest beat frequencies.

 

[agedhorse]

DC doesn’t exist in any form of audio amplification “outside the box”. Let’s knock that myth in the head.

The other thing is that thermally, when a signal is HEAVILY clipped can deliver more thermal power than an amp is rated for BUT generally the supply will sag so that the real thermal power delivered won’t be anywhere near the theoretical 2x maximum. Most will top out at about 125% of rated power… until the protection circuits trigger.

 

[mlowe]

The only thing that causes a speaker that is previously in good working order, to fail is exceeding it's electrical and or mechanical limits. I can send it a sine wave, square waves, severely clipped music or just straight up DC all day long. As long as I don't exceed the speaker's design limits it will be OK.
People think it's the clipped signal that killed their speaker because it died when they were clipping it. The truth is that they also happened to be exceeding electrical or mechanical limits, or both, while clipping.
THE SHAPE OF THE SIGNAL IS NOT WHAT HARMS SPEAKERS.

Under powering a speaker, by definition means not exceeding the speaker's limits.

You are well within your rights to believe otherwise, but when you spread misinformation to others, you are perpetuating the myth. If you want the truth you can either believe the design engineers, one of which (not me) has already weighed in on this being a myth. Or you can do all the work yourself to understand what is really happening.

Correlation is not causation.

"The truth is that they also happened to be exceeding electrical or mechanical limits, or both, while clipping."
Totally agree.

 

[monti2889]

Educate me on my ignorance....how is a "clipped" signal going to blow a speaker??? From what I've read of that theory....it would render every, overdrive, fuzz, distortion, and compressor/limiter (maybe not these two under normal conditions because they don't necessarily work in the same fashion as an OD type circuit) unusable, due to blowing the speakers. same with under power, never understood that either.
Take a hose...it handles 100psi....it's not going to burst if you put 50psi through it. (Maybe a slightly inaccurate analogy due to pressure, which would correlate to electromotive force...we commonly refer to that as volts, but Mr ohm said they're all related, I won't argue with him)
Wattage is the ABILITY for electricity to do work. Seems to me working something at half it's capacity, would just give it more headroom to handle peaks of extra workload.

 

[JACKSON JS1XM]

Any arguments I am involved in are done simply as a mere fledgling, disciple of the truth about speakers.
Wanted that to be clear.

Nobody came here to argue with you. I won't apologize for asking questions about the gear that was used to blow a speaker at 1/4 volume.

 

[JACKSON JS1XM]

First, I will point out some redundancies.
Impedance IS the load. You don't need to say it twice.

Just a couple of instances where Load Impedance is used redundantly. Someone else felt the need to combine the terms. They might know more than you or I, about why they did that.

The Use of Load Impedance in Circuits and its Effects on Circuit Functionality
Invalid Link Removed

"What is this impedance "auto detect" that you speak of? Tubes amps have some form of manual means to allow for different loads; either by using a specific jack, or by using a switch. Solid state amps specify a minimum impedance to use. Anything higher than minimum is OK, though usually at the expense of reduced output. But there is no "auto detect system that I am aware of.

"Something else in the amp didn't regulate the electricity. "The only "regulation of "electricity" is what goes on in the various power supply circuits. Sure a voltage regulator may not be functioning properly, but that in itself doesn't damage speakers. You need to connect the dots and explain how this might happen, so those less knowledgeable can learn from you.

Are you certain there isn't circuitry inside the amp box that doesn't "auto detect" impedance to protect or shut it down when impedance loads are an issue ? And look at that, yet another redundancy of "load impedance".

"Example load detectors and load detection processes are described herein. The example load detectors may be used in conjunction with amplifiers, such as audio amplifiers or any other suitable amplifiers, to detect a load impedance at an amplifier output."

Link Removed

 

[Old Garage-Bander]

Nobody came here to argue with you. I won't apologize for asking questions about the gear that was used to blow a speaker at 1/4 volume.

I think you are confusing the word argument for "fight", or "heated emotional discussion."
An argument is the expression of one side of a viewpoint in a debate. It does not necessarily carry any feelings of animosity towards the opposing view or the person arguing in favor of that view.

I hold no animosity towards you, nor do I believe I asked you for apology or expect one.

Just a couple of instances where Load Impedance is used redundantly. Someone else felt the need to combine the terms. They might know more than you or I, about why they did that.

The Use of Load Impedance in Circuits and its Effects on Circuit Functionality
Invalid Link Removed



Are you certain there isn't circuitry inside the amp box that doesn't "auto detect" impedance to protect or shut it down when impedance loads are an issue ? And look at that, yet another redundancy of "load impedance".

"Example load detectors and load detection processes are described herein. The example load detectors may be used in conjunction with amplifiers, such as audio amplifiers or any other suitable amplifiers, to detect a load impedance at an amplifier output."

Link Removed

That's some very compelling research you brought to the discussion. Thank you. I do not dispute it in the least as it stands.

Regarding the first item: As a recently retired broadcast technician of fifty years, I am very well aware that modern RF (Radio Frequency) amplifiers employ circuitry to measure impedance mismatches. They do this by comparing the reflected wave to the incident. If the resulting Standing Wave Ratio exceeds a certain preset limit it will first begin to dial back the RF stage output power. If the SWR reaches another higher threshold, or the detection circuitry trends too quickly in a direction that could damage the amplifier, it will shut off the RF output. This is relatively easy to do at radio frequencies. I have built and experimented with these types of SWR measurements circuits both for work and in my hobby of Amateur Radio. On the home front I have my own 100 watt transmitter. It also employs similar detection, measurement, and mitigation circuitry found in the higher power transmitters that I worked on throughout my career.

It is much more difficult to employ standing wave detection at audio frequencies. So other methods may be employed in audio amplifiers. It would be much easier to simply detect overheating of, or over current conditions in the final amplifier. This is done based on thermal or current conditions, not reflected waves. The detector does not use the measured impedance because unlike with RF systems where the impedances involved are fairly static and change slowly over a small range, impedances involved at the output of a guitar amp with a connected speaker, playing music, can change over a range of orders of magnitude. The actual impedance varies widely in spite of the nominal impedance ratings of an amp or speaker. While thermal or current shutdown circuits are used, I am unaware of audio amplifiers that measure and detect the impedances for the purpose of automatically switching output impedance of an amp, or shutting it down.

For your second link, I appreciate that you sourced Texas instruments. They are well respected for their research and innovations in many areas.
In reading the paper I see that they use the phrase "Load Impedance." I believe it is important to do that to make clear that they are not discussing other impedances. If there were any question about which impedances are being discussed, I'd do the same thing. However, by virtue of the arguments you and I employed in our debate, the nature of the impedance (the load) was already established. It is not wrong, but in this case I felt it was unnecessarily redundant. Was I splitting hairs? Certainly. Would this redundancy normally happen in a discussion between people with similar technical backgrounds? That also is up for debate. But coming from my background it raised a flag for me. YMMV.

Thanks for continuing this discussion. I must say I was disappointed at the thought that you might be bowing out early. I think we're just going to have to agree that we're coming at this from different viewpoints and possibly different backgrounds. I enjoyed it no less though because of that.

 

[mlowe]

Educate me on my ignorance....how is a "clipped" signal going to blow a speaker??? From what I've read of that theory....it would render every, overdrive, fuzz, distortion, and compressor/limiter (maybe not these two under normal conditions because they don't necessarily work in the same fashion as an OD type circuit) unusable, due to blowing the speakers. same with under power, never understood that either.
Take a hose...it handles 100psi....it's not going to burst if you put 50psi through it. (Maybe a slightly inaccurate analogy due to pressure, which would correlate to electromotive force...we commonly refer to that as volts, but Mr ohm said they're all related, I won't argue with him)
Wattage is the ABILITY for electricity to do work. Seems to me working something at half it's capacity, would just give it more headroom to handle peaks of extra workload.

Does

DC doesn’t exist in any form of audio amplification “outside the box”. Let’s knock that myth in the head.

The other thing is that thermally, when a signal is HEAVILY clipped can deliver more thermal power than an amp is rated for BUT generally the supply will sag so that the real thermal power delivered won’t be anywhere near the theoretical 2x maximum. Most will top out at about 125% of rated power… until the protection circuits trigger.

I agree it's always an AC signal however for a given time period the VC sees the signal as DC. This repeating generating the heat. I think this is where context in many statement on this thread get mixed up.

Check out this page from Makie.
WHAT IS CLIPPING? | MACKIE
This has always been my understanding but to be honest this thread has me thinking about this more carefully.

 

[mlowe]

I think you are confusing the word argument for "fight", or "heated emotional discussion."
An argument is the expression of one side of a viewpoint in a debate. It does not necessarily carry any feelings of animosity towards the opposing view or the person arguing in favor of that view.

I hold no animosity towards you, nor do I believe I asked you for apology or expect one.

That's some very compelling research you brought to the discussion. Thank you. I do not dispute it in the least as it stands.

Regarding the first item: As a recently retired broadcast technician of fifty years, I am very well aware that modern RF (Radio Frequency) amplifiers employ circuitry to measure impedance mismatches. They do this by comparing the reflected wave to the incident. If the resulting Standing Wave Ratio exceeds a certain preset limit it will first begin to dial back the RF stage output power. If the SWR reaches another higher threshold, or the detection circuitry trends too quickly in a direction that could damage the amplifier, it will shut off the RF output. This is relatively easy to do at radio frequencies. I have built and experimented with these types of SWR measurements circuits both for work and in my hobby of Amateur Radio. On the home front I have my own 100 watt transmitter. It also employs similar detection, measurement, and mitigation circuitry found in the higher power transmitters that I worked on throughout my career.

It is much more difficult to employ standing wave detection at audio frequencies. So other methods may be employed in audio amplifiers. It would be much easier to simply detect overheating of, or over current conditions in the final amplifier. This is done based on thermal or current conditions, not reflected waves. The detector does not use the measured impedance because unlike with RF systems where the impedances involved are fairly static and change slowly over a small range, impedances involved at the output of a guitar amp with a connected speaker, playing music, can change over a range of orders of magnitude. The actual impedance varies widely in spite of the nominal impedance ratings of an amp or speaker. While thermal or current shutdown circuits are used, I am unaware of audio amplifiers that measure and detect the impedances for the purpose of automatically switching output impedance of an amp, or shutting it down.

For your second link, I appreciate that you sourced Texas instruments. They are well respected for their research and innovations in many areas.
In reading the paper I see that they use the phrase "Load Impedance." I believe it is important to do that to make clear that they are not discussing other impedances. If there were any question about which impedances are being discussed, I'd do the same thing. However, by virtue of the arguments you and I employed in our debate, the nature of the impedance (the load) was already established. It is not wrong, but in this case I felt it was unnecessarily redundant. Was I splitting hairs? Certainly. Would this redundancy normally happen in a discussion between people with similar technical backgrounds? That also is up for debate. But coming from my background it raised a flag for me. YMMV.

Thanks for continuing this discussion. I must say I was disappointed at the thought that you might be bowing out early. I think we're just going to have to agree that we're coming at this from different viewpoints and possibly different backgrounds. I enjoyed it no less though because of that.

I can vouch for this. I think you have a good attitude. At the end of the day it's about learning and if that means at times any of us need correcting on a misunderstood element of knowledge it's for our own benefit. 73's btw.

 

[Old Garage-Bander]

To whom it may concern...
Why clipping is not D.C. (Direct Current).

The audio signal going to a speaker extends both above and the below the center line of the signal. (AKA the zero voltage point, the crossover point, or the resting position of a voice coil.) A.C. (Alternating Current) is called alternating because of these excursions above and below this point. The signal may be clipped, but it still has these excursions. Thus it is A.C.

For a signal to be D.C. the entire waveform must remain above or below the reference crossing point. You can turn an audio signal from A.C. to D.C. by rectifying it as shown below. It will be unusable however, for it's intended purpose, playing music.

The only thing that occurs with a speaker reproducing a clipped waveform is that the voice coil will, in theory, stop ever so momentarily, until the flat top portion of the waveform has passed. This does not however qualify that stopping point as being D.C. There will be a mirrored, or nearly so, corresponding conjugate, of the waveform doing the same thing on the opposite or ALTERNATE side of the crossover point.

There are many uses for rectified (turned into D.C.) audio. It's just that and audio amplifier output stage isn't one of them.

 

[agedhorse]

Educate me on my ignorance....how is a "clipped" signal going to blow a speaker??? From what I've read of that theory....it would render every, overdrive, fuzz, distortion, and compressor/limiter (maybe not these two under normal conditions because they don't necessarily work in the same fashion as an OD type circuit) unusable, due to blowing the speakers. same with under power, never understood that either.
Take a hose...it handles 100psi....it's not going to burst if you put 50psi through it. (Maybe a slightly inaccurate analogy due to pressure, which would correlate to electromotive force...we commonly refer to that as volts, but Mr ohm said they're all related, I won't argue with him)
Wattage is the ABILITY for electricity to do work. Seems to me working something at half it's capacity, would just give it more headroom to handle peaks of extra workload.

One way is when the duty cycle of a heavily clipped bass is much higher than average. This can increase the thermal power that a speaker has to dissipate, combined with potentially higher power under heavy clipping conditions. This would be pretty extreme however.

Generally I like to derate speakers used under such conditions by 50%. This was also the recommendation of JBL for the same reasons.

 

[S-Bigbottom]

The foil changes the directivity of the rabbit ears. You got lucky and it just happen to be in direction that worked for the station of interest.

Would you care to know how many reception issues I fixed for people by telling them to remove the regular antenna and use a paper clip instead?

Heck ya.

We are tired of getting into formation to watch a show.

 

[Old Garage-Bander]

Heck ya.

We are tired of getting into formation to watch a show.

That's danged clever of you. It happens to be we're watching Fox right now, though we rarely ever do.
But the Bug Eaters are playing Northwestern in Dublin Ireland.

 

[JACKSON JS1XM]

I think you are confusing the word argument for "fight", or "heated emotional discussion."
An argument is the expression of one side of a viewpoint in a debate. It does not necessarily carry any feelings of animosity towards the opposing view or the person arguing in favor of that view.

I hold no animosity towards you, nor do I believe I asked you for apology or expect one.

That's some very compelling research you brought to the discussion. Thank you. I do not dispute it in the least as it stands.

Regarding the first item: As a recently retired broadcast technician of fifty years, I am very well aware that modern RF (Radio Frequency) amplifiers employ circuitry to measure impedance mismatches. They do this by comparing the reflected wave to the incident. If the resulting Standing Wave Ratio exceeds a certain preset limit it will first begin to dial back the RF stage output power. If the SWR reaches another higher threshold, or the detection circuitry trends too quickly in a direction that could damage the amplifier, it will shut off the RF output. This is relatively easy to do at radio frequencies. I have built and experimented with these types of SWR measurements circuits both for work and in my hobby of Amateur Radio. On the home front I have my own 100 watt transmitter. It also employs similar detection, measurement, and mitigation circuitry found in the higher power transmitters that I worked on throughout my career.

It is much more difficult to employ standing wave detection at audio frequencies. So other methods may be employed in audio amplifiers. It would be much easier to simply detect overheating of, or over current conditions in the final amplifier. This is done based on thermal or current conditions, not reflected waves. The detector does not use the measured impedance because unlike with RF systems where the impedances involved are fairly static and change slowly over a small range, impedances involved at the output of a guitar amp with a connected speaker, playing music, can change over a range of orders of magnitude. The actual impedance varies widely in spite of the nominal impedance ratings of an amp or speaker. While thermal or current shutdown circuits are used, I am unaware of audio amplifiers that measure and detect the impedances for the purpose of automatically switching output impedance of an amp, or shutting it down.

For your second link, I appreciate that you sourced Texas instruments. They are well respected for their research and innovations in many areas.
In reading the paper I see that they use the phrase "Load Impedance." I believe it is important to do that to make clear that they are not discussing other impedances. If there were any question about which impedances are being discussed, I'd do the same thing. However, by virtue of the arguments you and I employed in our debate, the nature of the impedance (the load) was already established. It is not wrong, but in this case I felt it was unnecessarily redundant. Was I splitting hairs? Certainly. Would this redundancy normally happen in a discussion between people with similar technical backgrounds? That also is up for debate. But coming from my background it raised a flag for me. YMMV.

Thanks for continuing this discussion. I must say I was disappointed at the thought that you might be bowing out early. I think we're just going to have to agree that we're coming at this from different viewpoints and possibly different backgrounds. I enjoyed it no less though because of that.

Some topics I pick & choose my level of involvement, that's not bowing out, it's just selective input/contribution. I think a lot of bass amps have a light at the very least that warns as overload protections. Just one example, jump to page 6 of the pdf manual for the circuitry protections that almost any bass amp could possibly have. That particular model is a 500W solid state head. Could be the same one the OP has, maybe not ?

https://www.warwick.de/warwick/data/Warwick.de/Technical PDF/Manuals/LWA500_Manual_English.pdf

The problem with having that level of circuitry & overload warning, a part in the amp circuit goes bad and while the amp appears to function properly, the protection & warning system really doesn't function as intended. And when that happens the amp & speakers can be damaged to failure. That power has to end up as heat or excessive electrical power elsewhere that most likely doesn't handle the overload. And that's where something like a blown fuse applies. I responded to this thread to learn, maybe even come up with a suggestion of a solution to a problem. Something isn't right when a speaker blows at 1/4 volume and the speakers are designed to handle far more than what is assumed that was supplied to it. This discussion of a thread turned to AC vs DC electricity, both can damage parts, AC voltage & amperage is something that can kill a fellow. DC like the 9V battery variety isn't as lethal. Fires can even start from electrical connections inside the amp, and even ignite the cone of a speaker as a type of paper construction.

 

[monti2889]

FUOTE="Old Garage-Bander, post: 26755575, member: 274006"]To whom it may concern...
Why clipping is not D.C. (Direct Current).

The audio signal going to a speaker extends both above and the below the center line of the signal. (AKA the zero voltage point, the crossover point, or the resting position of a voice coil.) A.C. (Alternating Current) is called alternating because of these excursions above and below this point. The signal may be clipped, but it still has these excursions. Thus it is A.C.
View attachment 4794960
For a signal to be D.C. the entire waveform must remain above or below the reference crossing point. You can turn an audio signal from A.C. to D.C. by rectifying it as shown below. It will be unusable however, for it's intended purpose, playing music.

View attachment 4794964
The only thing that occurs with a speaker reproducing a clipped waveform is that the voice coil will, in theory, stop ever so momentarily, until the flat top portion of the waveform has passed. This does not however qualify that stopping point as being D.C. There will be a mirrored, or nearly so, corresponding conjugate, of the waveform doing the same thing on the opposite or ALTERNATE side of the crossover point.

There are many uses for rectified (turned into D.C.) audio. It's just that and audio amplifier output stage isn't one of them.[/QUOTE]
Forgive me for playing devil's advocate here, but as the speaker functions as a piston....doesn't it "momentarily stop" when it reaches full excursion and then begins to move in the opposite direction?

 

[Steve Dallman]

I was told this many times back in 80's/90's by manufacture's and service personnel; [maybe severe clipping can take out tweeter's.]

But the 'Myth' does have it's leg's and can take hold to those [like me] who don't have real knowledge on this subject through no fault of their own.

So your question in most cases is accurate.

The underpowered amp myth is oh, so not true.

 

[Old Garage-Bander]

Some topics I pick & choose my level of involvement, that's not bowing out, it's just selective input/contribution. I think a lot of bass amps have a light at the very least that warns as overload protections. Just one example, jump to page 6 of the pdf manual for the circuitry protections that almost any bass amp could possibly have. That particular model is a 500W solid state head. Could be the same one the OP has, maybe not ?

https://www.warwick.de/warwick/data/Warwick.de/Technical PDF/Manuals/LWA500_Manual_English.pdf

The problem with having that level of circuitry & overload warning, a part in the amp circuit goes bad and while the amp appears to function properly, the protection & warning system really doesn't function as intended. And when that happens the amp & speakers can be damaged to failure. That power has to end up as heat or excessive electrical power elsewhere that most likely doesn't handle the overload. And that's where something like a blown fuse applies. I responded to this thread to learn, maybe even come up with a suggestion of a solution to a problem. Something isn't right when a speaker blows at 1/4 volume and the speakers are designed to handle far more than what is assumed that was supplied to it. This discussion of a thread turned to AC vs DC electricity, both can damage parts, AC voltage & amperage is something that can kill a fellow. DC like the 9V battery variety isn't as lethal. Fires can even start from electrical connections inside the amp, and even ignite the cone of a speaker as a type of paper construction.

OK. Please re-read my post. I didn't accuse you of bowing out. I simply said that at one point, I thought you might be bowing out. I was glad you hung in and thanked you for doing so. That was a personal matter that I didn't have to share with you and everyone else here. But I did so in an attempt to re-reach out to you in the event that you were pulling away. I'm sorry that you saw it as something else.

Being relatively new here, there are some things that you may not have picked up on yet.

First... It is virtually impossible to perform a proper diagnosis of equipment problems in a forum such as this.
Even if we knew what amp and speaker was involved, it is more luck than anything else if someone suggests a fix and it turns out to be what the OP needed. As you'll recall the OP was very hesitant to describe any gear by name.
Amp repairs and related problems are tough enough when the thing is sitting in front of you on your workbench.

Second, learning involves more listening than talking. One of the things you will begin to understand is that there are a lot of bonafide experts on various subjects here. I do not count myself among them. However I have an extensive background in electronics troubleshooting. When I feel that something falls within my wheelhouse, I will offer what I can. I don't presume to know anywhere near what is known by these experts. So instead of telling them what I think, I try to rephrase what I want to say in the form of a question.

Third... I try not to get in over my head by repeating buzz words of which I am not very familiar. I know if I tried to impress people by stringing a bunch of techno-jargon together without a good understanding of what I'm saying, and how it might be seen for what it is, these guys are going to call me out on it.

Finally... If I do misspeak, (and it happens) I accept my error and move on. If instead I attempt to further talk my way out of it, especially by digging deeper into the techno babel that got me there in the first place, I know I'm going to just piss people off and get shut shut down hard and fast.

So my advice to newbies here, is to do a lot of watching, reading and to try to understand the culture of TB. That, in my opinion is the most valuable thing anyone can learn here.

I'll end by saying, I can not help you understand the mystery of the 1/4 volume speaker blowout. There is just not enough information about what went on leading up to that.

Maybe we can discuss another subject at some other time. 'Til then, it's been real, and it's been fun. Adios.

 

[JACKSON JS1XM]

I didn't accuse you of bowing out. I simply said that at one point, I thought you might be bowing out.

I'm good with that & understood it, didn't take it personal either. Just explaining what appears to be a bow out, night be others posting significant content in between anything I post. Anyway, this started going in other directions and I let that go without contribution/involvement because I wasn't going in that direction without any more details for what may have caused the blown speaker. I did learn my lesson though, a thread that doesn't have any details and never is forthcoming over several pages of posts with any details is 5 pages of wasting anyone's time.

 

[agedhorse]

An amp failure would have to be catastrophic before it would damage a speaker where the amp is rated at 25% of the true (not BS marketing) power rating.