Installing Crossovers and Wiring

After allowing the glop to harden up for about a week, we decided to move forward with crossover installation. The 1:1 mixed glop in the top of the cabinets was still pretty soft, but it was hard enough to not flow as the cabinets were put on their backs to install the tweeter crossover, or on their bottoms to install the woofer crossovers.

The first step was to install the binding posts. For most of the cabinets we used the binding posts provided with the North Creek kits, but some of them were used for our Thunder subwoofer cabinets because they were longer than others we could purchase, and were needed for the 1.5" deep rear panels. We substituted some binding posts from Parts Express on two of the Casita cabinets. They are very similar to those provided by North Creek. The Kitty Kats are to be bi-wired so two sets of binding posts were planned and we had to drill two additional holes so that four could be installed in each cabinet.

Tightening the nuts inside the cabinet proved to be difficult for the Parts Express posts, because the bolt was just slightly too big to fit inside our hollow-shaft nutdriver. So we used a very small Crescent wrench. We followed a North Creek suggestion to put an hex wrench through the wire holes of the binding posts to keep them straight and inline while tightening the nuts. The hex wrenches provided with each cabinet for the front panel fit perfectly and kept everything well aligned.

This photo shows the Casita crossover in place between the hole for the port tube and the binding posts (the cabinets are upside down).

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This photo shows the larger Kitty Kat tweeter crossovers in place. They are so large that they barely fit in between the port tube and the binding posts.

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After gluing the tweeter crossovers in place with liquid nails, the boxes were left on their backs for several hours for the glue to dry.

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The boxes were then rotated to sit upright for the first time since first layer of glop was applied more than three weeks earlier. It is now possible to see the braces at the top of the cabinet, the glop on the sides both front and back, and the space left for the woofer crossover. The thinner 2:1 mixture of glop dried very smooth and even, with almost no cracking. We just hope it does the job as well as the 1:1!

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This photo shows a closeup of the top brace and glop in the Kitty Kat cabinet. You can see the cracking in the 1:1 glop mixture and the unevenness due the to thicker mixture.

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The following photos show the tweeter crossovers viewed in a closeup through the bottom brace hole. Notice that much larger size of the Kitty Kat crossover, and the very small extra space between the binding posts and the crossover boards.

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This photo is a close up of one Kitty Kat tweeter crossover through the top brace hole showing the close proximity to the port tube hole. The actual space is about 1/4". We did confirm that our port tubes will clear the crossover.

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With the boxes resting upright, and the tweeter crossover glue drying nicely we dry-fit the woofer crossovers. In all cases the large woofer inductor will be glued with liquid nails to the bottom of the cabinet in the rear behind the center brace. The rest of the woofer crossovers are set with the longest dimension left-right in the front of the cabinet.

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Before gluing the crossovers in we took this photo showing a comparison of the relative size of the Kitty Kat and Casita crossovers and inductors. The Kitty Kats parts use larger gauge wire as well as having more total parts.

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This photo shows a Casita woofer crossover glued in place. Note that there is plenty of room for both the inductor in the rear and the board in the front.

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The fit is not nearly so easy for the Kitty Kat. As we discovered during our initial dry-fit before the braces and glop were added, the front part of the woofer crossover would not fit in the space provided. The following photo shows just how much it needs to be shortened.

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We removed any wires or lugs mounted to the Masonite base-board and trimmed about 1/4" from each end as shown in the following photo.

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We then reassembled the crossover wires and the board now barely fits in between glop covered side panels. Although were very careful in handling the crossovers, and tried to minimize bending the wires, a wire between the woofer inductor and the board broke during handling. The following photo shows the break. This happened after the woofer inductor was glued in place in the rear of the cabinet. Fortunately, the break happened at a junction on the board which was still unsecured, so we could repair it easily.

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We took the board to our workbench and under an illuminated magnifier, we carefully removed the silicone covering the junction along with some electrical tape covering the connection, which was soldered. The wire had flexed right at the solder point and broken loose. we stripped the insulation and re-soldered the wire. Fortunately we have a high wattage Metcal soldering station as a lot of heat was required.

The following photo shows the repaired junction, after the board was glued in place. We applied silicone after the photo was taken to restore the crossover to original condition.

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After all gluing was done, we again stacked the cabinets for a few days of drying and set up a fan to help speed up the process.

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Please see the next article in the series Wiring and Testing Crossovers

Copyright © 2010 David L. Bytheway