Is this bad

[squeak9798 5,000+ posts]

Pos rep for that! Very true. I've blown a sub with a 9v battery before, DC is bad news!

Unless you were testing a Funky Pup....I find that very hard to believe.

 

[RandyJ 10+ year member]

95Honda on SIN performed an experiment, and could not prove within the scope of his test that a clipped signal cause the driver to fail any sooner than a sinewave of equivalent actual power.
If I were in a slightly less lazy mood, I'd search for the link.

I remember that //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[helotaxi 5,000+ posts]

95Honda on SIN performed an experiment, and could not prove within the scope of his test that a clipped signal cause the driver to fail any sooner than a sinewave of equivalent actual power.
If I were in a slightly less lazy mood, I'd search for the link.

Even with a fully clipped signal, the speaker is still moving back and forth X number of times. That is still a substantial amount cooling going on.

How did he define "equivalent actual power?" RMS? The RMS of a Sine wave is .707 of the peak voltage time the current. The RMS of a fully clipped signal is the peak voltage times the current. The rated power of the clipped amp is somewhat less than the output at full clipping.

So as an example, if you had a sub rated for 600W and were running it with a 500W amp. The enclosure will allow the sub to handle the power, so mechanical power-handling is not an issue. You have a 500W amp. Can you blow the sub? Fully clip that amp and if the sub rating is truly a limit and not conservative estimate, that sub could be short of this world.

There are some other problems here as well. With impedence, there is impedence rise. Impedence requires AC. With a fully clipped signal, there is no longer an impedence, but rather Re becomes the driver resistance at the peaks. Now you have more voltage than normal through less resistance than normal. Now if you are just measuring actual power applied this is accounted for. Also consider that during these periods of high power application, there is close to zero movement of the cone.

I didn't see the test myself. A few questions about it. What was the quality of the driver used? Was it a quality unit with conservative power rating or was it a budget driver? How much power was used in relation to the rated power of the sub? If the power applied was nowhere near the real world power handling of the driver then the test is only of marginal validity. I fully agree that if you take an L7 or a XXX or something of that nature and run it on a fully clipped 500W amp you probably don't have much to worry about, but if you take a sub designed for a lower power you will need to be more careful with the gains, even with a relatively small amp.

 

[Chevillac 5,000+ posts]

Subscribe.

Imma learns sumthin

 

[RandyJ 10+ year member]

I didn't see the test myself. A few questions about it. What was the quality of the driver used? Was it a quality unit with conservative power rating or was it a budget driver? How much power was used in relation to the rated power of the sub? If the power applied was nowhere near the real world power handling of the driver then the test is only of marginal validity. I fully agree that if you take an L7 or a XXX or something of that nature and run it on a fully clipped 500W amp you probably don't have much to worry about, but if you take a sub designed for a lower power you will need to be more careful with the gains, even with a relatively small amp.

I believe the test was to prove that minimal power, fully clipped, could not blow ANY and EVERY driver. I believe at the time, people were argueing that a 10W fully clipped signal would destroy a XXX (not word for word, but some arguement similar to that).

 

[helotaxi 5,000+ posts]

I believe the test was to prove that minimal power, fully clipped, could not blow ANY and EVERY driver. I believe at the time, people were argueing that a 10W fully clipped signal would destroy a XXX (not word for word, but some arguement similar to that).

If that was the test, then um, duh?

 

[squeak9798 5,000+ posts]

How did he define "equivalent actual power?" RMS? The RMS of a Sine wave is .707 of the peak voltage time the current. The RMS of a fully clipped signal is the peak voltage times the current.

Yes, basic electronics //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif He ran two tests; Normalized voltage and normalized power.

I didn't see the test myself. A few questions about it. What was the quality of the driver used? Was it a quality unit with conservative power rating or was it a budget driver? How much power was used in relation to the rated power of the sub? If the power applied was nowhere near the real world power handling of the driver then the test is only of marginal validity. I fully agree that if you take an L7 or a XXX or something of that nature and run it on a fully clipped 500W amp you probably don't have much to worry about, but if you take a sub designed for a lower power you will need to be more careful with the gains, even with a relatively small amp.

Full details: http://forceaudio.com/viewtopic.php?t=26

Normalized power was a little more interesting. We could not prove within the scope of our test that a different signals of normalized power would have any different effects on the driver, regardless of the amount of cone excursion. Some people may still argue this, but it seemed pretty clear to us that weather a square or sine was put into a driver at a normalized power level, it still failed about evenly.

Two things to keep in mind;

1) This is only one test. But, it's the only test of it's kind that I'm aware of that directly tackles the issue. Everything else has just been two people discussing hypothetical situations. This is an actual, measured experiment.

2) This is limited to the scope of his test. He was paying for this out of his pocket, so obviously driver choice and quantity was limited since they would be intentionally driving the speakers into failure. A larger experiment with a higher quantity of drivers and of varying "level" of drivers would be interesting to see aswell.