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These look like killer drivers for the price. When I was at Parts Express 2 years ago for the speaker design competition I saw the prototype of these in the form of the 15" version. Note the 19mm XMax and very low for a 15" driver the 146 liter VAS.

Tom

http://email.parts-express.com/public/v ... 000008cc5c

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Walt

You might be able to do the Watkins alignment but the coils are equal impedance in these drivers which they are not in the Watkins driver. In truth, the woofers are capable of far more linear volume displacement than the Watkins so with DSP you should be able to blow the doors off the Watkins drivers. As far as I know the Watkins crossover is a passive way to deliver more power to the driver at resonance. However, if the driver is properly designed you should not need to do that. The fact that the impedance of a driver goes up at resonance and draws less power should be of no consequence because at resonance, mechanically the driver motor is moving the cone without much assistance from the amp. What you have to look at when resonance occurs is the Q of the driver. That will determine the response far more than the amplifier.

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Walt

Not surprised that your replacement woofers worked better that the ones from Watkins.

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Walt

Walt, Another option would have been to have the foam surrounds replaced keeping the Watkins design intact? Jim had that done to woofers in a pair of Green Mtn Diamontes that had surround rot, done locally.

Replacing foam surrounds is pretty easy, so long as you find good replacements. I was hesitant until I did it the first time, and found that it went much easier that I imagined. I was originally concerned about voice coil misalignment, and the need to remove the dust cap and put in a spacer in the gap between the voice coil and the pole piece. However, in the end, I just left the dust cap in place and just relied on the spider keeping things concentric and just carefully fitted the surround so that it appeared concentric with the same surround thickness. The biggest pain is cleaning off the old surround. With a plastic cone it easier, but I had paper cones, so needed to be careful to not rip or tear the edge under the old surround. The glue helps to cover up minor surface peeling of the paper cone during removal. Do it once, and you find out it is not as hard as you think.

A rotted foam surround is no reason to trash a driver.

David

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Walt