Greenie512

Small bookshelf speakers [Project No 4]

Firstly let me sing the praises of Dennis Murphy the designer of these speakers refer to his site for full details: -

http://murphyblaster.com/content.php?f=main.html

Dennis can be contacted here or he’s often found at the Madisound speaker forum:

http://www.madisound.com/cgi-bin/discuss.cgi

Hiquphon OW1 tweeter - http://www.hiquphon.dk/
supplied by - http://www.zalytron.com/

Seas CA15RLY mid/woofer - http://www.seas.no
supplied by - http://www.madisound.com/ (including crossover parts)

Design Procedures

As Dennis provides a full drawing of the cabinet there really is no need for design. However I always redraw the cabinets in Visio which: -

1. Helps me thoroughly understand the build/construction
2. If (as in this case) original dimensions are imperial then I can re-dimension into metric and double check.
3. Make minor dimension adjustments to make measuring out/cutting easier [but maintaining internal volume as per original design]
4. Draw a cutting schedule for the board available, in this case a 700 x 2400 x 18 mm plywood off cut.

Redesign to available tools, I’m pretty poor at woodwork so I’ve been buying some electric power tools to make up for my lack if skills!! My sliding compound drop saw’s maximum cut is 300 mm so I designed around that (for the height) and made the speaker fractionally wider to compensate.

I sneaked a horizontal shelf in as a additional bit of bracing

Tweeter rebate might look a bit “shallow” but I’m adding 1.5 mm ply veneer to finish which will come flush with tweeters when installed.

That’s “expansion joint foam” on the under side to the top I’ll apply it to all internal areas where practical.

The 18 mm plywood was a off cut from a sheet of “seconds” I used to build my work benches with; so finish is pretty rough and edges are very laminated (bits missing) so I decided to use Liquid Nails to glue everything and fill voids/gaps. Once dried I cut/clean out any seepage on exposed faces.