Chromecast Audio Speaker V2

Following the relative success of my first ChromeCast Audio speaker, I have decided to build another. Despite not getting around to finishing off the cases, both the original prototype and a second production speaker have been in almost daily use. Both sound good for the price of the speakers, with the original prototype sounding nicer to my ears, mostly because of the slightly larger drivers (5.25" vs 4") and a slightly large box volume. I have uploaded a video of the production speaker to my you tube channel DIY Home Build Multiroom Speaker where I discuss the build.

As mentioned in the video the new version will utilise the aclaimed Overnight Sensations design by Paul Carmody. I am hoping this will give a significant increase in sound quality. Paul's design uses the Hivi B4N woofer and Dayton Audio ND20FA-6 tweeter

Hivi B4N and Dayton Audio ND20FA-6

Hardware

I am sticking with the 15W per channel TA2024 amps , mostly because I bought several already, and they sound fine.

12V 15W TA2024 Amplifiers

Revised Design

This time I designed the enclosure in Autodesk Fusion 360. I have opted for a more adventurous cabinet shape, which will again be constructed from slices of 1 inch MDF. Unlike the first design I will be separating the woofer chambers and using Fusion 360 I was able to determine that I need 8 x 1 inch slices to obtain the 4.5 litres volume per chamber required by Paul Carmody's design. I am hoping the finished speaker will look like this.

New design rendered from Fusion 360.

One of the issues with the construction of the original cabinet was making the MDF slices the same shape. Using Fusion 360 to model the cabinet design I have been able to 3D print a router template so that all the slices are exactly the same size and shape. I had to print this in 3 pieces that were then glued together.

3D printed template

Using the telplate I marked out the cabinet shape on the MDF slices.

Marking out using the template.

I rough cut the MDF slices using a bandsaw, drill, and jigsaw.

Rough cut MDF slices

Then I attached my 3D printed template with double sided tape and used a flush cut bit in my router table to trim the slices to their finished shape.

Flush trimming the MDF slices

The finished slices turned out really nice..

Rough cut MDF slices

Next was glueing the slices together to form the speaker cabinet. This was actually quite a pain, as the slices kept sliding around on the glue. I ended up glueing just one slice at a time and using some weights to hold them in place. Glad the weights came in useful for something!

Glueing the MDF slices together to form the speaker cabinet

I then planed and sanded the cabinet.

Planing and sanding the cabinet.

The cabinet was cleaned with a tack cloth to remove any dust and then I applied paint to the cabinet with a roller. I used a product called Tuff Cab from Blue Aran, a specialist speaker company located about 5 mins from where I work. Tuff Cab is a specially formulated speaker cabinet paint that dries to a hard wearing waterproof surface. It requires no sealing and is applied directly to bare wood/plywood/MDF. With a small roller it is easy to apply and leaves nice uniform surface.

Painting the cabinet with Blue Aran tuff Cab.

Once the first coat is dry I will sand it to further elininate the slice joints. Very pleased so far.

Planing and sanding the cabinet.

More to come soon.......

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