Final Assembly of Casitas

After one night of listening, we took another evening off to rest. Then we set about to finish the Casitas, and set them up for listening tests. We did test all drivers and crossovers earlier and marked each driver for its channel. We ran the burn-in signal on the drivers sitting out of the fascia for approximately 24 hours.

Gluing Casita Fascia to Cabinets

We decided to glue the fascia to the cabinets before mounting the drivers, largely because of a suggestions from George Short about how to handle the port tuning straws. We were worried about how to access the straws once things were buttoned up. The concern is that the bundle of straws is so tight inside the port that it would be difficult to slide them forward or back. We sent an email to George Short at North Creek Music asking if he had any hints about how to accomplish the port tuning. We were also curious about the different straw bundle length mentioned in the older and newer Kitty Kat drawings. He responded:

"About the tuning and the straws, there have been two different port tubes used in construction and that is the source of the difference. But you can try several different lengths, there [are] plenty of straws to work with.

"You can have the straws sticking out of the cabinet instead of sticking in, that is what I do, until the perfect length is determined. The longer the effective port tube, the lower the tuning, and the straws just in the middle and not sticking out still forces laminar flow at high volumes.

"When you determine the perfect length, measure it, take out the tweeter, and have them stick in."

Of course (administers a self head-slap) it is obvious! This makes it possible to easily slide the straw bundle, and as a result we decided to glue in the fascia. We suspect that the last of the box resonances will be solved once the fascia are glued in tightly. As a result we stuffed the Dacron into the boxes as instructed, and the glued the fascia in place using the Part Express provided screws to act as clamps. The sizing of the pre-cut fascia obtained from North Creek provided a good tight fit and gluing went very easily and the boxes sound much more solid and dead than before.

This photo shows the three Casita boxes stuffed, glued and ready for drivers.

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We also decided to make simple labels for the rear panels so we could tell the left channel box (with the twister circuit) apart from the center channel (which has the same tweeter position as the left channel).

This photo shows the labeled boxes The straws can be seen inside the ports.

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Mounting Casita Tweeters

We began with the tweeters. The Casitas were purchased as a match pair with a third added for a center channel. As a result, the matched pairs of tweeters and woofers were packaged together in shipping. We were careful when handling them to keep them from getting mixed up, and marked them during the crossover testing so they could be put back into the same place during final assembly.

This photo shows the North D28 tweeters in boxes, the match pair on the left.

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Here is a tweeter ready to mount.

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This photo shows the left channel tweeter up close showing North Creek part number and serial info. All parts come well marked and in this case we also have frequency response plots with the serial numbers.

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We used a power screwdriver original purchased for electronic chassis assembly to mount all drivers. The MDF presents a significant load and drag, and a firm hand is required to not allow the driver to skip or slip on the screws. In addition we were very careful to not allow the driver to slip and damage either the driver or fascia. Although plenty of woodworking, painting and other mistakes were made, at least we did not have a single slipped screw mark on any of the Casitas or Kitty Kats.

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Here are the three Casita cabinets with the tweeters mounted

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Mounting Casita Woofers

The Castia Woofers were similarly boxed as a matched pair, and we marked them during crossover assembly as well. The woofers come well packed in a plastic bag with spacers in the mounting holes to protect the cone, especially if it is sat on a surface.

Photo of a woofer in the plastic bag.

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Photo of a woofer showing the spacers in the mounting holes

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The woofers come with a nice rubber protective cover over the magnet assembly. Since these woofers have been modified with an addition bucking magnet, they are significantly deeper than standard. During dry fitting of the cabinets, we decided to remove the protective cover as it interfered with the bracing and crossover. We removed the covers and moved the serial numbers from the cover to the magnet assembly.

Photo showing the magnet cover

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Here is the woofer with the cover removed and the spacers placed inside it.

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The woofers have very small and fragile quick connects, much smaller than those found on the Kitty Kat woofers, and we were concerned about them and used great care. In the assembly instructions, George Short advises to carefully tighten up the quick connects so that they make good contact as follows:

"If the quick connects are loose, the way to tighten them is to pinch them back by the solder joint to the wire with needle nose pliers. Be very careful not to pinch the open end that goes onto the drivers. Then, as the quick connect is slid onto the driver lead it will get tighter and tighter as one pushes on."

We found that they were all very loose and had to be tightened. The following photo shows how this is done.

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Here is a photo of a woofer with the quick connects attached. Note the relative small size of the quick connects and speaker terminals compared to the large wires from the crossovers.

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Mounting a woofer

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First Listening Tests

After the assembly was complete we carried the Left and Right Casitas to our living room to audition them along with our Kitty Kats. We connected the Casitas to the "A" output of our Creek 5350SE integrated amp, and the Kitty Kats to the "B" output so we can directly compare.

The Kitty Kats are designed to be near wall, and as such we have been listening with them spaced approximately 3" from the back wall. The Casitas are designed to be place away from a wall. For this initial test we placed them side by side, knowing that this is not optimum, but it would give us a chance to run some signals and break-in. The following photos show the left and right pairs. The finishes turned out pretty well after all.

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The holes for the fascia mounting screws are unfinished as we need to put in grill attach points on these. The following photo shows the rear side of the Casita with the straws approximately 1/2" out of the port. This is the initial position for our listening tests. We do not intend to tune the ports until more break-in time has been accumulated.

Castia Port with straws about 1/2" outside the cabinet.

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Kitty Kat Port with the straws about 1" outside the cabinet.

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The Right Channel pair form the back side

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So now we let the listening and tuning begin. We expect to take several weeks of listening and perhaps even some measurements to be made before we settle on the final port tuning and speaker position. Of course, neither of these speakers is intended to end up in our living room, but the Casitas as the Left-Right pair of our home theatre system (with all Casitas and a Thunder Subwoofer) and the Kitty Kats are intended to become our recording monitors with a matching Thunder Subwoofer for each side, with our own custom designed active crossover.

Please see the next article in the series A Weekend of Listening

Copyright © 2010 David L. Bytheway