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Building Lee's version of the Waldforf
Hello all,
I'm the guy building the prototype of Lee's interpretation of the classic Waldorf scoop loudspeaker. I've never heard a Waldorf cabinet but I've been a long time fan of the old JBL 4520 and 4530 scoop loudspeakers. Lee was kind enough to share with me his drawings for a dual driver cabinet that was inspired by the classic Waldorf cabinets as designed by Richard Long so many years ago. I jumped at the chance to build a prototype and will most likely build a pair.
I started the project by scaling Lee's drawing to extract dimensions and angles for the cut pieces. I used AutoCAD's TrueView 2012 (available from the AutoCAD site for free) to do that. After making the cut list, I transferred the shape of critical parts to poster board for use as templates to make the cutting process easier and repeatable. Below is a PIC of the template for the 'driver bucket end caps'. Each cabinet requires three of them.
Attachment 54807
I made them by ...
#1) Cut 3 pieces roughly to size and stacked them up and tacked them together for machining and easy handling using a brad gun.
#2) I transferred the shape to the wood using the poster board template
#3) I I rough cut the wood with a bandsaw to a shape that was a half inch larger than the finish part and then ...
#4) Trimmed off that half inch using a table saw to get a clean edge and flat surface that was the finish size.
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Building Lee's version of the Waldforf
I cut the rectangle panels from full size sheets using my Festool plunge saw. What a great tool! It cuts as clean and accurate as a traditional cabinet saw but is portable and stores away on a shelf when not in use.
Attachment 54808
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Building Lee's version of the Waldforf
The first assembly to go together was the driver bucket. This portion of the cabinet is the most difficult portion to build because it is made up of multiple angle cut pieces. Below is a PIC of the assembled driver bucket upside down and without the bottom board applied.
Attachment 54809
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Building Lee's version of the Waldforf
Having proven myself stupid too many times, I've learned the hard way that it is always wise to dry fit the pieces before committing to 'glue & screws'. Here is the driver bucket being test fit for squareness and the expected clearance between panels. You can see in this PIC the two added braces to center make rigid the top of the driver bucket.
Attachment 54810
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Building Lee's version of the Waldforf
This PIC show two more templates that will be used to make the lower section of the horn flare that attaches to the driver bucket as well as the supports for the scoop that is at the horns mouth.
Attachment 54811
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Building Lee's version of the Waldforf
Everything fits so it's time to glue and screw the top and back panel to the first side panel. You should notice that a reflector has been installed in the upper back corner of the cab.
Attachment 54812
Building Lee's version of the Waldforf
That's it for this week's installment. This a weekend project for me. Unfortunately my day job and other responsibilities obligate me to other things during the week. I plan to continue this build and will post my results as I move along. My long term intent is to load the cabinet with a pair of JBL 2240's and measure the results. The panel between the driver bucket and the lower cavity will be made in such a way as to allow me to test changing the size of the resonant cavity immediately behind the drivers. I've got some other drivers that I want to try in this cab as well. One of them is an aging Altec 604. I am curious just how much usable upper band I can squeeze out of it.
I want to thank Lee for sharing his design with me. It's been fun to build!
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Best Regards,
Carl Huff