Wattage ratings of a driver

[Marvel]

Righto Michael. It was Community, and it worked. Just like the light bulb tweeter protection in one of the xover designs for the LS/Khorn/Belle.

[Trey Cannon]

Trey,

Do you determine the power handling of a K-77- F above crossover the same way?

Yes, only at the time we pulled that number, we only tested for 2 hr not 8hr. We refer to "Appendix C of AES2-1984 (r1997) for set up and testing.

I'm curious to know how much an "F " will handle. We have heard anywhere from 2 to 5 watts.

The 77 can take about 10 watts max within bandwidth. However, you need to stop thinking of this in watts / power.

Think voltage.

I realize that the overtones in most music, that would be fed through the network to a K-77-F, are many dB (20 or more?) lower than the midrange and bass.

That's not a bad number to use. I can't get any closer than that as a rule. If you were to pick one speaker and drivers complement, then you can get much closer.

Also does the rule of thumb that peak handling is about 6 dB higher than continuos (4 x on a wattage basis) apply for tweeters as well?.

NO, it just applys to systems. To get a system power number you must look at the weakiest link in the chain looking "through" the network. As the woofer loads the system the most, it is, for the most part, what sets the power ratting.

Thanks

[DrWho]

The fact that music tends to have less content in the upper registers does not affect how the speakers are tested...

What you don't see when looking just at the power input capabilities of the tweeter is that it is more efficient than the woofers - which means it doesn't take as much power to achieve the same SPL. For instance, if the tweeter is 3dB more sensitive, then the tweeter will need half as much power to achieve the same SPL. This is where the crossover comes into play...reducing the voltage delivered to the tweeter to achieve a flat frequency response. So if the tweeter can play 124dB and the woofer can only do 120dB, then you don't have to worry about the individual power handling of the tweeter as long as the frequency response is made flat by the crossover. Since no matter how you look at it, whatever power that is needed to achieve 124dB with the tweeter will never be delivered unless the woofer blows up first. Perhaps that's a bad example since tweeters clasically tend to blow first, but that's because of other issues not relevant to this example.

[garyrc]

Doc, are these the "other issues" that tend to blow tweeters before woofers? Are there more? Trying to avoid them all .... I blew an old K-77 back in about 2001 (test tone preset at a higher level than I realized), and don't ever want to do that again!

High frequency byproducts due to amplifier clipping

Test sweeps or steady test tones that are too loud for the tweeter.

In the Old Days: 1) Zipping between stations without muting the tuner 2) Winding or rewinding audiotape at high speed which produces frequencies octaves higher than spec, 3) reflections picked up by TV antennas that send very loud broadband noise through the tweeter