Myth Or Fact: Under Powering a Subwoofer?

[hispls 5,000+ posts]

It would be nice if we could skip all technical crap and give someone an answer in simpleton terms and leave at that.

This often happens and is likely the source of most of the persistent myths and recurring bad information.

 

[dagormz]

Am I wrong by keeping it simple and saying distorted signal to speakers? Who cares about technical definition at this point when some that does not understand electrical is trying to get a simple and understandable answer.Also for example reasons who cares what a what a sub can take. I was saying that we are not always underpowering sub's.

It would be nice if we could skip all technical crap and give someone an answer in simpleton terms and leave at that. This way when they want learn the technical aspect they are not afraid of the answer.

I wasn't pointing this at you. Your information was consise. The other dudes information was wrong.

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[trumpet 5,000+ posts]

Why Too Little Power will NOT blow Your Speakers

I agree with hispls. To add to that, audio reproduction is entirely based on science, yet it doesn't take a college degree to understand clipping and distortion. At some point one has to buck up and learn the science. It's not that hard. Not everything can or should be boiled down to childlike simplicity.

 

[What was that? 10+ year member]

I do agree with your overall thought trumpet, I just wish when some starts their question with "I'm new to this" people wouldn't jump in with a bunch of crap to show other people on the forums how smart they are. Simple answers that make people comfortable are far more likely to encourage them to further their technical knowledge. I would say 1 out of 4 people I help tell me they tried to get help online first but people filled them with so much info they were not yet capable of understanding that is was belittling. Or just being as****e's because they didn't know basics. That scares people away instead of getting them interested. Half these people doing it really do know a lot but don't dumb it down enough so other people can learn a lot.

 

[gckless 5,000+ posts]

[quote name='dagormz']umm, i know i'm kindof new to car audio but i have a decent background in electrical engineering. Isn't clipping when your HU puts out a distorted signal in which has a flat signal at the crest and though of the sine curve essentially giving DC current to the speaker, making the coil stick for a second and stressing it a lot. I don't believe clipping has anything to do with RMS rating. Just that @What was that\?; putting 5k into a 150 sub. It doesn't blow because it probably has a decent cone and he probably has a HU that gives a clean signal.[/QUOTE]

Clipping drives your power up exponentially. You are correct in what it physically does. And I'll bet $100 right now that no speaker rated at 150W will take a clamped/measured 5kW and not blow.

 

[bubbagumper6 5,000+ posts]

Am I wrong by keeping it simple and saying distorted signal to speakers? Who cares about technical definition at this point when some that does not understand electrical is trying to get a simple and understandable answer.Also for example reasons who cares what a what a sub can take. I was saying that we are not always underpowering sub's.

It would be nice if we could skip all technical crap and give someone an answer in simpleton terms and leave at that. This way when they want learn the technical aspect they are not afraid of the answer.

Clipping is a form of distortion yes but it's not the only form.

 

[dagormz]

I do agree with your overall thought trumpet, I just wish when some starts their question with "I'm new to this" people wouldn't jump in with a bunch of crap to show other people on the forums how smart they are. Simple answers that make people comfortable are far more likely to encourage them to further their technical knowledge. I would say 1 out of 4 people I help tell me they tried to get help online first but people filled them with so much info they were not yet capable of understanding that is was belittling. Or just being as****e's because they didn't know basics. That scares people away instead of getting them interested. Half these people doing it really do know a lot but don't dumb it down enough so other people can learn a lot.

Well, I don't know as much about car audio so I wanted to explain why I believed his response was wrong in a scientific way that I understand. Not trying to start a fight.

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[dagormz]

Clipping drives your power up exponentially. You are correct in what it physically does. And I'll bet $100 right now that no speaker rated at 150W will take a clamped/measured 5kW and not blow.

I just used his setup as an example. In a short form, clipping is not too much power, it's distortion from the hu or amplifier.

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[LosIsATool 5,000+ posts]

Why is this still going.. If it was bad everytime you are not listening to full volume they will blow, everytime the load rises or voltage drops they will blow. You can say maybe there could be a cooling problem, no so because it won't heat up enough to hit thermal.

 

[shizzzon 10+ year member]

Dagormz- Clipping is not once again a dc current.

Speakers do not work on DC, only AC. If clipping were dc, then as soon as you overdrive the rail, literally, the coil would catch on fire and of course there is no sound reproduction on DC either. That doesn't sound like a well thought out amplifier.

What was that? - Dumbing down?

You can live your life having everything dumbed down but don't preach it to us to live the same way.

This right here is a PRIME EXAMPLE of why the US is no longer on the edge of discovery any longer and why other countries have been catching up with us for the last 30 years or so.

The USA is not the country innovators of science are looking at as the #1 choice for exploration into space.

We used to be but because of viewpoints like this, dumbing down the education of the country's population causes that population to not care because they are "dumbed down" to not realize how important exploration is.

And yes, we are talking about science and this is heavily relevant.

Watch the following video. I have tagged it right where it needs to start, only a minute of it where i tagged it is where you need to see.

I DO encourage to watch the full video but this is a pure example of what i'm talking about-




Conclusion- There is no cutting corners in research and education. Those who do that need not work in the fields that interest them.

 

[trumpet 5,000+ posts]

I just used his setup as an example. In a short form, clipping is not too much power, it's distortion from the hu or amplifier.

I'm singling this out because it highlights a major part of the mystery of the myth that underpowering a speaker will kill it. #1 clipping is not merely distortion. Distortion is anything that happens to the waveform that changes it from the source. All amplifiers create some amount of distortion, and it's not always audible and it certainly is not always harmful. #2 This neglects the time factor. Speakers overheat and die from too much heat over a long period of time. A 0.1 ms peak of clipped power is not going to thermally kill a speaker. A 30 second duration of clipped power is a much longer period of time for heat saturation to occur. #3 That 30 seconds of clipping still does not mean a speaker will fail! If it's 100W hard clipped and the subwoofer is built to handle 500W there should be no reason for that 500W subwoofer to fail.

I'm not going to go into this any more because this discussion has been done so many times in so many forums. Instead I am linking a video that I feel is a must-watch for anyone who enjoys car audio, especially if you have a bit of experience and you're looking to step up your game.

[video=youtube;85mWsMJOh-8]

 

[inferno1985 10+ year member]

when i started out in car audio i had people and a select few shops tell me that underpowerng your sub lower than rms with cause it to fail.

i believed it for a minute untill i got better information about it all.

the people that gave me that bs idea that underpowering will cause damage, basically said that when the sub moves it is cooling off the voice coil. so if you are not running enough watts to the sub it will not move as efficiently and just keep the coil hot..

thats what i was told in my newbie months in car audio 15 years ago. haha

 

[What was that? 10+ year member]

Shizzon - I clearly didn't dumb down my point enough for you to understand me.

Dumbing down does not mean (to me) taking away the facts or details of an item or situation. It is simply breaking the information down and redistributing the facts or details in a way the uninformed can understand. If dumbing down was not necessary in some form we would start middle school science with quantum physics and pee wee football with the Erhardt/Perkins offense. From the video you linked, which I liked, you view dumbing down in a different way than I do. I do agree that we should not make things simple because some don't want to go through the process of learning.

 

[shizzzon 10+ year member]

Ok, how about this-

What if you asked me about this topic here, underpowering a speaker.

I could give you the entire explanation of why it's not possible... because, etc and how things work..

Or, i could only give you the answer as no.

This scenario works at the occupational level.

You can either know a bunch of facts or solutions as to how to do this or that..

But when something new comes along, you wouldn't know what to do because you do not understand the functionality of the design.

I think that's worded correctly to understand my point.

It's not about just knowing the quick version of the answer but understanding why that answer is correct.

 

[Jepalan]

Here is an unclipped sine wave...

Here is a HEAVILY CLIPPED sine wave...

Just looking at them - **which one is spending more time putting MAX output voltage across the sub**?

Heavily clipped amp outputs are much more likely to fry the voicecoil. During the full-on portion of the squared sine wave a *lot* of current is flowing through that low impedance load.