Tin Tuirtle Design

Finished measuring the Cornscala's

clock January 12, 2013 15:25 by author Bald Turtle

I had a small get together at the house for some guys who are into DIY audio. They were gracious enough to come out, bring some of their own speakers, and then do an analysis of my Cornscala's.

DIY audio event

audio analysis of Cornscala

Frequency Response

frequency response Cornscala


Cornscala Impedance

Bottom grills are in place

clock January 7, 2013 15:51 by author Bald Turtle

I finished fabricating a second pair of grills for the lower cabinets on the Cornscala's. I ruined a yard of fabric and lost a day or so by not sizing them correctly. I am just not a great upholstery guy, and I still am not happy with the results. But for now they will do and the woofers are protected. Not sure yet what I will do about the uppers. The fabric is from Bob Crites and is the same as what is currently used on the Klipsch Heritage series speakers.

Cornscala in room

Textured Paint Technique

clock January 3, 2013 05:29 by author Bald Turtle

I tried two techniques for doing the textures for the Cornscala's. I knew that the textured area would be problematic for cleaning, and I wanted to try and solve that. I also was looking at what the difference would be like between using a truck bed liner versus a pebble spray. And last I had to make sure the various layers of products would all be compatible, especially as the assembly would be complete and irreversible before the final laquer process.

This picture shows the sample piece, with the pebble spray texture on the left, and the truck bed liner on the right.

This sample sat in the corner of the shop while I finished spraying the Cornscala's, so it was covered in dust and grime. I wiped it down with a regular paper towel and Endust. It came away completely clean with very minimal fuzzing from the towel. The products and order of application is below:

I chose to use the textured paint for the speakers. A couple of things to think about. Doing it again I would go to 3 coats and maybe 4 of the Multi-Color Texture. The whole idea is to get a uniformity of texture and color so it has a nice finished look and feel. You get a much nicer even look by doing multiple light coats of the texture. The Varicure is tough as heck, and will stand up to a lot of household cleaners even though it is a laquer. I don't know that I would go wiping it off every day, but for normal cleaning I would think it should last for a very, very long time.

The truck bed liner is a good option, but it is hard to notice the texture without angled light. It ends up just looking like flat black paint from a distance. I tend to want a more grainy surface and now that I am comfortable with being able to clean it this is a good choice for me.

The Cornscalas sound great!

clock December 22, 2012 03:00 by author Bald Turtle

I really want to do a long post or project page and explain exactly how these all went together, but there is just no time at all for that now. Here are a few pictures. They sound so, so good.

Corncala with cherry and walnut cabinets

Cornscala satin laquer finish

I love the backs. The whole design has this vintage feel, and they sound great with many types of music. I still need to break them in to see what I really have, and I would like to get someone to measure them sonically.

Corncala backs with brass screws

The little mini audio stand works well and it gave me an extra 5 inches or so on the front so I could tighten everything up.

audio rack made with cherry and walnut

Finished spraying

clock December 20, 2012 12:48 by author Bald Turtle

The final coat of laquer went down a few hours ago and it looks like I will finally be able to put the living room back together tomorrow. The new products I am using on this project have been great, and the results are pretty good. The guys over at Chicagoland Finishing Materials were extremely helpful. They really took the time to listen to me about my project, my equipment and then make a recommendation. I went with the Chemcraft Variseal and their Varicure precat laquer.

mini audio stand

Chemcraft Variseal topcoat

Upper cabinets

clock December 17, 2012 16:54 by author Bald Turtle

The upper cabinets have been a pain to complete. I went ahead and reinforced the tops, got the batting in and a support for a cross brace. The motorboards were installed, and finally the dampening was completed. FINALLY, I think I can spray these.

Cornscala upper cabinet

Cornscala Upper Cabinet Dampening

More Cornscala build pics

clock December 16, 2012 18:21 by author Bald Turtle

Here are a few more pictures from this evening. The first shows the bottom and how it overlaps the butt joint on the lower part of the cabinet. This helps reinforce that joint that is holding all the weight of everything above it.

Cornscala Cabinet Feet

Then a picture of the front of the upper cab with the textured side panels in place. This shows how far back the panels extend to reinforce those vertical walls.

Then a shot of the final bit of work this evening. I took the spare motorboard that I blew up with the router and used it to test fit the horn. Now I can build the support in the back to hold that driver. Gotta love a wave guide that is as big as your head.

Cornscala mid horn

Lower cabs are ready

clock December 16, 2012 11:54 by author Bald Turtle

Put the footer and feet on the lower cabs, and followed that up with sealing the motorboard to the front. The seperator piece is attached on top, everything is sealed and ready for laquer tomorrow.

Cornscala Woofer Cabinet

The backs were put in place and pre-drilled for the brass screws. They still need to be sanded before spraying.

Cornscala cabinet backs

Cornwall bass motorboard

clock December 11, 2012 17:11 by author Bald Turtle

The bass section from the Klipsch Cornwall uses a modified motorboard design that moves the ports from the bottom to the side. This allows the 15" woofer to be mounted directly in the center of the motorboard. The assembly is a two piece design. If I build another pair I think I will change a couple of things. One, I will mill a rabbet for the outside diameter. The 3/4" drop is slightly too deep, and the 15.625 diameter is overly large. Other than that the assembly fit the speaker perfectly, and a test fitting to the cabinets was also perfect.

Here is the double sided tape method I use to cut the circles out of the MDF. This attaches the MDF to the backing/waste board so that when the circle is finally cut free it doesn't move around and cause a problem.

cutting a speaker hole

using a Jasper Circle Guide to cut a speaker hole

Klipsch Cornwall motorboard parts

Cornscala motorboard

Prepping for final finishing coat

clock December 8, 2012 19:01 by author Bald Turtle

The lower enclosures were dampened with carpet padding and automotive headliner fabric. Just some minor dampening to breakup any resonance that might happen, and help to clean up things for a little more clarity. A friend helped me with the final sanding prep using 400 grit. I learned a lot about final prep work, and these cabinets are really looking great. I did a quick stacking of the components to check proportions and get some idea as to what they will look like complete.

Cornscala dampening

Cornscala cabinet assembly

Goose Island Night Stalker

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