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Re: RS 40-1354 Specs at last

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In Reply to: Re: RS 40-1354 Specs at last posted by Paul Joppa on December 13, 1999 at 10:52:05:

Thanks for doing the tests.
So I get enclosure volume of .738 cubic feet and port length of 3.66 inches with a 2 inch diameter. Correct?
Using
Enclosure volume Vb = 15 * Vas * (Qts ^ 2.87)

Tuning Frequency Fb = 0.42 * Fs * (Qts ^ -0.9)
Lv = ((1.463 * (10 ^ 7) * (R ^ 2))/(Fb^2)*Vbi)-1.463 * R
where Lv = length of the port
R is radius of the port (diameter /2 ),
Vbi is Vb in inches (cu ft * 1728)

If you have two drivers in the box do you just multiply by two?

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Re: RS 40-1354 Specs at last Paul Joppa 11:19:34 12/14/99 (0)
That sounds about right. Two caveats though:
1) I tested drivers right out of the box. With some breakin the stiffness of the suspension will drop, lowering resonance and Q (10%?)and raising Vab (20%?). Should give very similar results though.
2) Used with no-feedback triode amps, the QE will increase due to the source impedance. Usually 30-50% increase results - see Eduardo deLima's articles in GA. That gives a much bigger box, but another 1/2 octave of bass. If you don't allow for this, the bass may be underdamped and boomy. I have no information on the excursion capability of these drivers, however - there's a limit to how much bass you want from a 6" woofer!
Re: RS 40-1354 Specs at last Doc B. 09:12:45 12/14/99 (0)
For two drivers you just double the box volume and double the vent area. The vent length stays the same.

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