Pushing a cabinet - Question

[walterw]

This has been covered over and over again.

If "clipping" caused woofers to die, guitarists and bass players who use distortion would be replacing speakers every gig.

OK, let's see how short we can do this:

"clipped amps do way more power than they're 'supposed to', and it's squashed, continuous power with no chance for the voice coil to cool off. if that power is too much for too long, bye bye speaker."

how's that?

 

[s0c9]

If "clipping" caused woofers to die, guitarists and bass players who use distortion would be replacing speakers every gig.

Sorry.. (no offence intended) but baloney.. you are confusing distortion on the input side with output clipping... clipping your amp causes DC current/square wave (the peaks are "clipped") and turns your speaker coils into the equivalent of the electric stove heating element.. heating them up and melting the wax surrounds. This is most often caused by under-powering your speakers.. hence the 1.25 to 2.25x RMS/Program power rule of thumb for powering them.

 

[cheapbasslovin]

Sorry.. (no offence intended) but baloney.. you are confusing distortion on the input side with output clipping... clipping your amp causes DC current/square wave (the peaks are "clipped") and turns your speaker coils into the equivalent of the electric stove heating element.. heating them up and melting the wax surrounds. This is most often caused by under-powering your speakers.. hence the 1.25 to 2.25x RMS/Program power rule of thumb for powering them.

I can't tell if you're serious or not. Square wave is square wave is square wave, it doesn't matter where in the signal path they're made.

'Underpowered' means overpowering an undersized amp, creating an excess voltage a higher percent of the time than a clean running amp; this really isn't underpowering at all.

 

[s0c9]

I can't tell if you're serious or not. Square wave is square wave is square wave, it doesn't matter where in the signal path they're made.

'Underpowered' means overpowering an undersized amp, creating an excess voltage a higher percent of the time than a clean running amp; this really isn't underpowering at all.

It sure makes a difference to your speakers when it's on the output side of your amp..
"Underpowering" is amp output relative to the RMS rating of the speaker being powered, caused by excess input voltage. In short, meaning you don't have enough amp for the cab.
And yes, underpowering your speakers will blow them more often than overpowering.

 

[cheapbasslovin]

Underpowering IS overpowering.

If your amp is rated 50w and your speakers are good for 1000w you'll smoke that amp long before you can do any damage to those speakers no matter how much square wave the output produces. If it were truly underpowering the tiny amp could smoke big speakers. The tiny amp can only smoke itself.

The square wave does nothing more than compress the signal. When the amp is doing the clipping that means the amp is exceeding it's max rating and it is sending a full voltage signal that stays at full voltage more of the time than if it weren't clipping. The short version is the amp is outputting a higher RMS voltage than it is rated for. This makes speakers smell bad when they are only rated slightly higher than the the amp rating.

 

[walterw]

...clipping your amp causes DC current/square wave (the peaks are "clipped") and turns your speaker coils into the equivalent of the electric stove heating element..

sub-myth #1, the "square waves=DC current" thing. nope. (the "electric stove heating element" part is right, but that's got nothing to do with the shape of the wave, only the amount of power.)

 

[Downunderwonder]

Far out soC9, you've had serves from Bob Lee, QSC, and Agedhorse of Mesa, and you're still trotting out the same nonsense. If I was in charge you'd get a week off for trolling.

 

[Bass_Pounder]

It sure makes a difference to your speakers when it's on the output side of your amp..
"Underpowering" is amp output relative to the RMS rating of the speaker being powered, caused by excess input voltage. In short, meaning you don't have enough amp for the cab.
And yes, underpowering your speakers will blow them more often than overpowering.

Incredible........

With all of the resources on this forum ignorance is still bliss

 

[s0c9]

Far out soC9, you've had serves from Bob Lee, QSC, and Agedhorse of Mesa, and you're still trotting out the same nonsense. If I was in charge you'd get a week off for trolling.

Sorry, but "serves"? What is a serve.. and the Bob Lee I know usually identifies himself on forums... so not sure what you're getting at.

 

[Bass_Pounder]

Sorry, but "serves"? What is a serve.. and the Bob Lee I know usually identifies himself on forums... so not sure what you're getting at.

Go back and read my earlier post.......

Search for posts by AgedHorse (engineer from Genz-Benz and now Mesa), Bob Lee from QSC, Bill Fitzmaurice, etc.

Those gentlemen have more then enough explained that clipping is not DC, and underpowering does not damage woofers.

ETA - This is also covered in the Amps section FAQ's. The knowledge is out there. It is up to the non-believers to educate themselves.

 

[s0c9]

If your amp is rated 50w and your speakers are good for 1000w you'll smoke that amp long before you can do any damage to those speakers no matter how much square wave the output produces. If it were truly underpowering the tiny amp could smoke big speakers. The tiny amp can only smoke itself.

Well, no duh! on the 50w amp!

But - unless you know what you are doing - the average user sure can smoke those 1000w speakers by [underpowering] with a 750w amp (driven to extended clipping) much faster/quicker/easier than powering those same speakers with a 1300w amp.

 

[EastCoastThump]

^Well, it's not quibbling to note that in that case you'd be smoking speakers by *overpowering* them with a nominally rated-750 watt amp that's capable of putting out well above 750 watts (b/c it's being hit with a hotter-than-spec input signal or b/c it's is being run at higher THD levels than specified in its power rating).

You're right that the amp's rating @ spec doesn't guarantee the safety of your speakers when the rig's driven beyond spec (b/c those specs don't identify the upper limits of the power an amp can deliver), and you're right that a rig with an amp driven into higher levels of distortion can be hard to monitor for speaker fatigue. (Of course, there's generally some real territory north of the amp's rated THD but south where it's so ragged that it masks speaker farting.)

Whether I'll be more likely to toast a cab's drivers by overpowering them with a nominal 750 watt amp at higher THD levels or a 1000 watt amp at lower THD levels depends on how the components match up. With a lot of cabs, you'll hear the drivers complain well before you push even a 750-watt amp into higher wattage/higher THD territory, in which case a 750 watt, a 1000 watt, or a 2000 watt amp will give me pretty much the same sound as I push into power levels that will kill my drivers.

If your amp is far more capable than your cabs, you can be sure that any distortion signals your speakers nearing their limits—if your basic tone is clean. With clean bass rigs, it's perfectly possible to use amps much more robust than the cabs, as long as you spend the time to learn how your components interact and what the cabs are capable of. If you don't know what you're doing, it's easy to smoke a small cab with a big amp either by diming the amp right away, by not paying attention to how your speakers respond as you slowly increase volume in a controlled environment, or by pushing your new rig on a loud gig before you have any feel for how loud it gets in its safe zone.

 

[cheapbasslovin]

Well, no duh! on the 50w amp!

But - unless you know what you are doing - the average user sure can smoke those 1000w speakers by [underpowering] with a 750w amp (driven to extended clipping) much faster/quicker/easier than powering those same speakers with a 1300w amp.

You can't have it both ways. If you are calling it underpowered lower power should mean as much or more damage, if the output square wave is the culprit. You are providing too much voltage without allowing the speaker to cool. In any world that is overpowering. As I said before, overloading an undersized amp.

Or, in the immortal words of Inigo Montoya, "You keep using that word. I do not think it means what you think it means."

 

[Vanceman]

Either s0c9 is messing with you guys, or based on his join date, he really doesn't know. Just sayin'.

 

[s0c9]

You can't have it both ways. If you are calling it underpowered lower power should mean as much or more damage, if the output square wave is the culprit. You are providing too much voltage without allowing the speaker to cool. In any world that is overpowering. As I said before, overloading an undersized amp.

Look, you can split hairs on semantics all day long.. if "You are providing too much voltage without allowing the speaker to cool" because you're "overloading an undersized amp" causing it to clip and toast the speaker, then you underpowered the speaker.. pure and simple. And with that I'm done discussing the topic...

 

[Downunderwonder]

Horse lead to water spits in it instead of drinking.

 

[David Jayne]

Look, you can split hairs on semantics all day long.. if "You are providing too much voltage without allowing the speaker to cool" because you're "overloading an undersized amp" causing it to clip and toast the speaker, then you underpowered the speaker.. pure and simple. And with that I'm done discussing the topic...

Sounds like you're referring to the 'square waves cause the speaker to freeze during the flat peaks and valleys' myth.

 

[David Jayne]

David Jayne thermalled his cab just the other day. It's easy with a big amp and less lows. I posted all about it on the first page but got overtaken by noise.

Yes, 500w amp into 400 watt speaker. It got hot and smelled bad but still works fine. Hope it continues to.

yeesh; i'm guessing it was in the middle of a bunch of Too Damn Loud? or was it just too small a cab for the job?

Not really that loud. Borderline ear plug volume.

 

[Bass_Pounder]

Look, you can split hairs on semantics all day long.. if "You are providing too much voltage without allowing the speaker to cool" because you're "overloading an undersized amp" causing it to clip and toast the speaker, then you underpowered the speaker.. pure and simple. And with that I'm done discussing the topic...

Sounds like your the one with terminology problems.

After reading your posts in the "power amp for subs" thread, it is easy to see that you are not willing to take advice and learn.

Please expect to keep being corrected over and over again.

 

[walterw]

to be fair, we might be quibbling about definitions.

if s0c9's definition of "underpowering" is using an amp that's just a little too small and driving it into clip in an attempt to get volume so that it's now too much, that's one thing. in that case, "underpowering" means "not bringing a big enough amp to do the gig cleanly", not "providing less power to the speakers than they're rated for".