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Dr 280 compatible 12 inch speaker?

Posted: Wed Sep 25, 2019 8:10 pm
by Starchild
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?

Re: Dr 280 compatible 12 inch speaker?

Posted: Wed Sep 25, 2019 8:31 pm
by Seth
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.

Re: Dr 280 compatible 12 inch speaker?

Posted: Wed Sep 25, 2019 9:09 pm
by Bill Fitzmaurice
It may be used, but the short xmax makes it less than ideal.

Re: Dr 280 compatible 12 inch speaker?

Posted: Wed Sep 25, 2019 9:26 pm
by Starchild
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.

Re: Dr 280 compatible 12 inch speaker?

Posted: Wed Sep 25, 2019 9:29 pm
by Bill Fitzmaurice
There's no minimum drive voltage.

Re: Dr 280 compatible 12 inch speaker?

Posted: Wed Sep 25, 2019 10:40 pm
by Starchild
Thanks for the info much appreciated.

Re: Dr 280 compatible 12 inch speaker?

Posted: Fri Dec 27, 2019 8:29 am
by Starchild
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? :?:

Re: Dr 280 compatible 12 inch speaker?

Posted: Fri Dec 27, 2019 11:20 am
by Seth
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

Re: Dr 280 compatible 12 inch speaker?

Posted: Fri Dec 27, 2019 12:50 pm
by Bruce Weldy
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.

Re: Dr 280 compatible 12 inch speaker?

Posted: Fri Dec 27, 2019 11:12 pm
by Seth
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.

Re: Dr 280 compatible 12 inch speaker?

Posted: Thu Feb 11, 2021 8:14 pm
by burnsze15
Question,

If the Fs of a chosen driver is 54 (In Limits) Vas is 66 (in limits) Xmax of 6.5mm (exceeds min limitation), however the Qts is slightly below the .3 min at .23 with a high Bl of 24 and a Mms of 49 what will be the consequences in terms of performance of the low Qts? (Qes is .23 and Qms is 11.36)

(Would the slightly excess excursion act as a mitigating factor to the slighly low suspension?)

Thanks.

Re: Dr 280 compatible 12 inch speaker?

Posted: Thu Feb 11, 2021 10:22 pm
by Bill Fitzmaurice
Low Qts results in a loss of low frequency response. There are many drivers that have the correct specs, so there's no reason to settle for a driver that doesn't.

Re: Dr 280 compatible 12 inch speaker?

Posted: Mon Feb 27, 2023 4:10 pm
by tribal king
Hi guys. This is my profile/thread (or whatever ya call it) which for some reason I have no access to anymore. Is there any way I could regain access to it? Bill a little help over here! lol

Re: Dr 280 compatible 12 inch speaker?

Posted: Mon Feb 27, 2023 4:21 pm
by Bill Fitzmaurice
I don't understand.

Re: Dr 280 compatible 12 inch speaker?

Posted: Mon Feb 27, 2023 10:35 pm
by Seth
If I understand correctly, tribal king and Starchild are one in the same. Guessing he lost the log in info for the Starchild account.