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project, but this did not compromise the design, as this is all that was required to obtain

my goals.

In all variations, the woofer crossover is a 2nd order electrical topology providing

roughly a 4th order Linkwitz Riley acoutstic transfer function at 3450 Hz. The tweeter is

3rd order electircal, and providing a reciprocial 4th order LR function. The impedance

minima is 3.5 ohms, so we must consider this a 4 ohm design. The phase plot shows

good phase tracking as well.

network. Not unusal in a crossover design, the LP and HP sections sum to a impedance

of nearly 50 ohms below the crossover frequency. This will result in response variations

when driven by higher output impedance tube amplifiers, The circuit shown below is a

notch filter to linearize the impedance without affecting the speaker acoustic response

This is accomplished by installing the network before the crossover. While this can

make for a significant improvement when connected to tube amplification, it will provide

no benefit at all if the speaker is driven by a low impedance solid state amplifier. The

additional components will run you an additional ten bucks per speaker, should your

needs deem it necessary to include it in the design.

Note the BOM shows the 2.5 ohm resistors as 2.4 ohm. Use what you have, as it will

make little if any difference. The 2.5 ohms are available at MAD.

L1011 1.2 mH P-core p/n 255-102

(original was 1.15 mH)

C1021 15 uF p/n 027-934

Tweeter:

C2011 3.9 uF p/n 027-022

L2021 0.15 mH 18 ga p/n 255-206

C2031 10 uF p/n 027-932

R2041 2.4 ohm p/n 004-2.4

R2051 2.4 ohm p/n 004-2.4

L1011 1.0 mH p/n 255-100

(steel laminate or P core)

C1021 20 uF p/n 027-436

Tweeter:

C2011 4.3 uF p/n 027-419

L2021 0.15 mH 18 ga p/n 255-206

C2031 10 uF p/n 017-932

R2041 2.4 ohm p/n 004-2.4

R2051 2.7 ohm p/n 004-2.7

C0021 20 uF p/n 027-436

L0021 0.25 mH 20 ga p/n 255-026

Dayton ND20FB PE p/n 275-030

if placed closer to the wall.

Copyright 2007 Wayne Wendel and Curt

Campbell

Free for non-commercial use.

Campbell

Free for non-commercial use.