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Freq. Resp. for the Betsy-K

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Karl,

The response below 150hz is completely dependent on the enclosure. Those measurements were taken on a standard measurement baffle, which is to say, not in a box. So, what you are seeing in the low frequencies is a result of the driver Q. As you can see, the Betsy, with it's Qts of .78, provides bass in an OB, even that small-ish one! That also means it is ill suited for all but giant boxes. The BetsyK, and any other speaker with a medium or low Qts, will not. They need a resonant enclosure of some sort. (Aside from circumstances that greatly raise the effective Qts, for example, an amplifier with a very high output impedance would raise the effective Qes of the BetsyK, potential enough to make it usable in an OB).

Plug the Betsy and BetsyK into any box simulation software, and use a sealed enclosure of 1000L. You'll see pretty much the similar lines to those in the response charts. Don't look at driver response charts for bass. Plug the T/S specs into a simulation program.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers
 
Paul -

I appreciate the information on the low end response. However, I am interested in the top end. Your graph shows the Betsy-K to be be more ragged and to drop off faster than the Betsy. If this is correct, then I will be more likely to try a tweeter from the start.

Regards,

Karl
 
Karl,

I haven't corrected the page. Buying and learning Dreamweaver is on my long list of things to do. I wouldn't call the difference between the two drivers substantial. The BetsyK does go a little higher, but the difference is above 15Khz and still only a couple of db at 20k. Either way, as with all fullrangers, the limiting factor isn't absolute extension, it's dispersion. I like the controlled dispersion up high as it provides more placement flexibility via less interaction with surroundings. For example, if you wanted to put a little bookshelf close to the floor, you wouldn't get reflection problems up high like you might with a small diameter tweeter. Still, those wanting a broader sweet spot or some additional sparkle may opt for a little help. You could start with something cheap but efficient (piezo?) rolled in very high. I'm perfectly happy without any sort of tweeter, and my ears only have 30 years on them.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers
 
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