bonnie & jason

Zaph Audio SR71 DIY Speakers

By jason, February 3, 2010 on 2:24 am | In alissa | 2 Comments

I had this setup as a separate blog page originally. Now that they’re done, I’m archiving here.

To go with the amplifier project, I’m building a set of speakers. This DIY community is also very active and has lots of resources available. I chose to build this kit from Zaph Audio and Madisound.

It’s a two-way system with a 7″ reed/paper pulp cone woofer and a ferrofluid cooled tweeter with a pre-coated fabric dome. The kit includes a crossover (this determines to what level what frequencies the woofer should produce and which frequencies the tweeter should produce) as well as all the hardware needed to put them into cabinets.

The cabinets can be bought pre-made, but I decided to try to build my own per the design specified by Zaph Audio. Here’s what they would look like if I had bought the cabinets (for like $300.)

I still haven’t decided the details… but it will either be MDF or plywood or solid hardwood… or some combination thereof. More to come.

1.23.2010
I went to Macbeath lumber today and got a piece of African Mahogany. It wasn’t cheap, so I figured I’d use it for the front, top, and rear panels and just use plywood for the remaining sides. This way, I get a nice two toned look and don’t have to deal with veneer or paint. I’ll just sand and tung oil and be done with it. Need to pick up some tools still, but I’ll probably make some rough cuts on the table saw.

1.28.2010
Got some work done on the cabinets the last few days:

The kit from Madisound came in as well. Everything looks pretty much as expected. Should be able to get a lot done this weekend as well. Still have to cut the holes for the drivers and cups. Then rabbet and chamfer the woofer holes. Then glue the front and rear baffles in before rounding over the edges. After that, I think it’s just sand and put some tung oil on it and they’re done. Except for the actual wiring install of the drivers and crossover.

1.29.2010
Got a little bit more done today. Made a couple small mistakes though.

1. I should have rabbeted the baffles vertically to insure flat surfaces to mate to the cases (my table saw is kinda so-so.) As it is, my glue job may have some small gaps. I’ll have to take a look after I trim and roundover to see if there are indeed gaps and if so, fill in with some sawdust/wood glue.
2. My initial countersink for the woofers was a tiny bit too small. About 0.10″ or so. I didn’t realize this on the first one until after I cut out the thru hole. I was able to sort of kluge together the little circle I cut out back in place so I could use the jig again with some backyard engineering so that worked out ok I think.
3. I probably should have made the countersinks a little deeper. I haven’t tried it yet, but I’m not sure I’m going to be able to get the drivers in flush after I put the gasket in. I figure I could always add more gasket to build up to flush if necessary.

Well, hopefully tomorrow I can get them trimmed and rounded over. Then sanded and tung oiled.

1.30.2010
Trimmed all edges and rounded over the front baffles:

2.3.2010
I got them all done today. Soldered the connections up and added the stuffing. Installed the crossover and drivers and voila!

I still have to get them broken in and I haven’t figured out what I’m going to do about speaker stands yet. But I’m pretty happy with how they turned out. And I’m looking forward to setting them up properly with good amplification.