Dr 280 compatible 12 inch speaker?

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Starchild
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Dr 280 compatible 12 inch speaker?

#1 Post by Starchild » Wed Sep 25, 2019 8:10 pm

Hey guys quick question. Is the Eminence Kappa 12a good enough to work in the DR280?? Does it's parameters fall within the 10% loophole?

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Re: Dr 280 compatible 12 inch speaker?

#2 Post by SethRocksYou » Wed Sep 25, 2019 8:31 pm

Preferred driver T/S specs / Kappa12a
fs 35-55Hz / 45Hz
Qts .30-.50 / 0.27
Vas 60-120L / 112.1L
xmax no less than 4mm / 3.2mm
A rising response into the midrange is required.

https://www.eminence.com/pdf/Kappa_12A.pdf

The response chart for the Kappa 12a doesn't look like rising midrange to me, Qts is only a smidge out of spec but still out of spec, and the 3.2 Xmax is below the minimum.

Doesn't look like an option to me. But I'm sure Bill will verify one way or the other.

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Bill Fitzmaurice
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Re: Dr 280 compatible 12 inch speaker?

#3 Post by Bill Fitzmaurice » Wed Sep 25, 2019 9:09 pm

It may be used, but the short xmax makes it less than ideal.

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Re: Dr 280 compatible 12 inch speaker?

#4 Post by Starchild » Wed Sep 25, 2019 9:26 pm

Thanks for the quick response guys! Oh and Bill I got 2 of them for some time now and I am just edging to use them till I get a pair of the Deltas. Use as in mainly for testing at home. What voltage would be good enough?

PS:This is temporary I repeat TEMPORARY.

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Re: Dr 280 compatible 12 inch speaker?

#5 Post by Bill Fitzmaurice » Wed Sep 25, 2019 9:29 pm

There's no minimum drive voltage.

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Re: Dr 280 compatible 12 inch speaker?

#6 Post by Starchild » Wed Sep 25, 2019 10:40 pm

Thanks for the info much appreciated.

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Re: Dr 280 compatible 12 inch speaker?

#7 Post by Starchild » Fri Dec 27, 2019 8:29 am

Bill Fitzmaurice wrote:
Wed Sep 25, 2019 9:29 pm
There's no minimum drive voltage.
Update: gonna try out 1 of the cabinets today, :hyper: quick question Bill... Based on the mentioned t/s parameters what should be the max drive voltage on the Kappa 12a? :?:

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Re: Dr 280 compatible 12 inch speaker?

#8 Post by SethRocksYou » Fri Dec 27, 2019 11:20 am

Awesome! Have fun and let us know how it turned out :thumbsup:

It's rated for 450 Watts

To figure Volts from Watts, calc the square root of Watts times Ohms.

450 Watts x 8 Ohms = 3600
SqRt of 3600 = 60 Volts

My guess is it will be in distortion well before that point

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Re: Dr 280 compatible 12 inch speaker?

#9 Post by Bruce Weldy » Fri Dec 27, 2019 12:50 pm

SethRocksYou wrote:
Fri Dec 27, 2019 11:20 am
Awesome! Have fun and let us know how it turned out :thumbsup:

It's rated for 450 Watts

To figure Volts from Watts, calc the square root of Watts times Ohms.

450 Watts x 8 Ohms = 3600
SqRt of 3600 = 60 Volts

My guess is it will be in distortion well before that point
Bill's rule of thumb in past years has been to calculate based on half of the thermal wattage rating. In this case, that would make it around 40 volts. Of course, the caveat is that the high pass crossover point determines how much juice you can put to it.

If you are crossing at 100hz, I would think 40 volts would be very loud and safe.

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Re: Dr 280 compatible 12 inch speaker?

#10 Post by SethRocksYou » Fri Dec 27, 2019 11:12 pm

Bruce Weldy wrote:
Fri Dec 27, 2019 12:50 pm
Bill's rule of thumb in past years has been to calculate based on half of the thermal wattage rating. In this case, that would make it around 40 volts. Of course, the caveat is that the high pass crossover point determines how much juice you can put to it.

If you are crossing at 100hz, I would think 40 volts would be very loud and safe.
Nice! I hadn't read that little morsel of information before. Thanks for passing it on Bruce :thumbsup: Definitely makes sense for mids/highs.

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