If you've ever seen the inside of a pair of Klipsch Chorus I loudspeakers, then you know that the crossover looks like a PCB sandwich.
While it's possible to recap them as is, I chose to reconstruct the crossover networks in the Klipsch Heritage tradition; on wooden planks.
Remaining faithful to the original design, the high pass consists of a 3rd order Butterworth filter with two 2uF capacitors in series split between a parallel 160uH inductor. The low pass is a 2nd order Butterworth filter that employs a 3mH inductor in series and a 68uF capacitor in parallel with the low frequency driver. The bandpass filter is a 2nd order Buttwerworth design that makes use of a 7uF capacitor in series with a clamp in the form of one 15 ohm 12 watt resistor and a parallel 3mH inductor. The bandpass also contains the famous Klipsch autoformer to achieve inductive attenuation for the midrange horn.
The crossover frequencies are 650 Hz and 7000 Hz.
I reused the autoformers as well as the inductors (all air cores) from the original crossovers. 15 ohm 12 watt Mills non-inductive resistors as well as 250V Dayton PMPC 1% precision audio capacitors were used for the signal path. 100V Dayton NPE 5% capacitors were used to parallel the woofers. Solder is 60/40 rosin core. All parts were purchased from Parts Express.
2" stick on felt pads were adhered to each rear corner of the crossover boards. Boards were then screwed to the rear baffle of each speaker box in Klipsch Heritage fashion.
Parts list:
(2) 005-15: Mills non-inductive 15W 12 ohm resistor
(4) 027-200: 2uF Dayton Audio PMPC 1% precision audio capacitor
(2) 027-238: 6.8uF Dayton Audio PMPC 1% precision audio capacitor
(4) 027-214: .1uF Dayton Audio PMPC 1% precision audio capacitor
(2) 027-356: 68uF Dayton Audio 5% non-polarized electrolytic capacitor
(2) 090-872: NTE 25-B600-02 2 pole 25A panel mount barrier terminal strip
(4) 090-878: NTE 25-B600-06 6 pole 25A panel mount barrier terminal strip
(2) 49927: 4-Pack Everbilt 2" self-adhering stick-on felt pads
(1) 080-512: 10 Pack - Cable tie screw mounts
As Dayton does not sell a 7uF 1% capacitor, I used one 6.8uF 1% capacitor in parallel with a pair of .1uF 1% capacitors in each crossover.
I am pleased with the resulting sound. The dynamics and detail that come out of these things are scary good. Imaging and staging are excellent. Instrument and vocal positions are obvious and remain fixed. Coherence and separation have been notably improved. Specific instruments are easier to pinpoint and follow, especially through complex pieces of music. Highs are quite a bit more crisp and airy. Cymbals and high hats now have genuine presence. Midrange frequencies are significantly more clear and posses substantial weight. The final product is an emotionally engaging music experience with a forward yet non-fatiguing overall balance.
