[cyberspyder]

For my wood shop summative, I've decided to make some DIY bookshelf speakers. Normally, MDF would be use, but to cut that during class time would require having respirators and goggles for all 24 guys. So no MDF.

BUT I have scrounged up some 3/4" Baltic Birch/Russian Plywood as a substitute, which will get here on Monday. I plan to duplicate a set of Zaph's Bargain Mini's, although with a few tweaks of my own.

1) Recess the baffle into the 4 sides
2) Do a 3/4" roundover on the front of the sides
3) Have a recessed back

Preliminary side sketch:



Front drawing (from Zaph's page):

Baffle detail (also from Zaph's page):

Dimensions are 9 1/4" deep, 10" tall, and 6 1/4" wide

Crossover Components:
-2x Bennic wirewound 4ohm resistors
-2x Bennic wirewound 5ohm resistors
-2x 10uF Solen/SCR/Bennic/Clarity Caps Poly capacitors
-2x 2.7uF Solen/SCR/Bennic/Clarity Caps Poly capacitors
-2x 3.3uF Solen/SCR/Bennic/Clarity Caps Poly capacitors
-2x 1.5mH Solen/other brand 18-20ga inductors
-2x 0.25mH (or close to) Solen/other brand 18-20ga inductors
-2x 0.1mH Solen/other brand 18-20ga inductors
-Speaker wire as ICs between the Xover & woofers/tweeters/binding posts
-63/37 0.20-0.32" dia. solder

Vendors: Solen, Madisound, PartsExpress, any other reliable DIY place

Cabinet Parts:
-5' x 5' 3/4" Baltic Birch/Russian Plywood (this is the size it comes in, you only need half of that for a pair, with lots to spare)
-1" dia. x 4" Port tube (I couldn't find any 1" dia. PVC tubing at Home Depot or Rona, so I had to buy special port tubes)
-2x MCM 4'' Shielded Aluminum Cone Woofer (Part #: 55-1853)
***Remember to get the source code on the flyer (here), as it'll get you a discount (only if the woofer is on sale)***
-2x Aurasound NT1-204-8D 3/4" Titanium Dome Tweeter
***DO NOT TOUCH THE DOME***
It is out of stock with a lead time of at least 4 weeks, a substitute (same size & mounting method), BUT IT IS NOT RECOMMENDED, is below
-2x Dayton ND20FB-4 Rear-Mount 3/4" Neodymium Dome Tweeter
-1/2" Sonic Barrier Dampening
-1 1/4" Sonic Barrier Dampening
OR
-1/2" Chopped foam carpet padding doubled (or tripled) up
***To judge whether chopped foam is good or not, hold it up to the light. There shouldn't be many pinpricks of light shining through. This type of material is pretty much the only cost-effective damping material for speakers. It's really not that bad.***
-5/16" OR 1/4", 1 1/2" long socket cap screws (black)
-5/16" OR 1/4" Tee nuts
-4x Binding posts
-Various sizes of heatshrink

LOG

March 10, 2008
-Ordered parts

March 15, 2008
-Some parts arrived :rock::

March 17, 2008
-My plywood arrived, except it was the wrong thickness...

March 18, 2008
-Some crappy pics of my workspace:

March 19, 2008
-PE order arrived, along with my wood!

Hmmm, whats in the PE box?...

Some books and...

MY TWEETERS...

Close-up of the protective cap & tweeter

Along with my 18mm (sigh...they don't make it exactly 3/4") Baltic Birch

Dramatic angle shot showing all 13 plies

March 26, 2008
-My Mini-RCA IC parts arrived (Canare Star-Quad, Switchcraft connectors)

March 27, 2008
-IC done (Canare StarQuad, Switchcraft connectors), Mini-RCA:

March 28, 2008
-My woofers arrived and I began cutting the wood to width

March 29, 2008
-The last of my parts arrived, some perfect lay inductors and wirewound resistors from Solen
-Soldered all the wires to the woofer and tweeter, all preliminary work done, have to wait until enclosure is done

Brendan

 

[infinitesymphony]

I'm not sure if that picture is representative of your final speaker, but if you recess the driver too far into the enclosure, it may cause some undesirable reflections off of the baffle. Just a thought, anyway.

 

[error401]

Were you able to find the Aura NT1?

 

[cyberspyder]

Nope, hence using the ND20 as a temporary sub-in....will see if I can get it in a month. If not, then I'll have to stick with it.

@ infinitesymphony, what do you mean recessed? I think I got you confused...instead of the baffle being bolted over the sides, it's now recessed into the cabinet, while preserving the same volume.

 

[infinitesymphony]

Quote:

Originally Posted by cyberspyder /img/forum/go_quote.gif @ infinitesymphony, what do you mean recessed? I think I got you confused...instead of the baffle being bolted over the sides, it's now recessed into the cabinet, while preserving the same volume.

Ah, gotcha.

 

[cyberspyder]

PE order arrived, along with my wood!

Hmmm, whats in the PE box?...

Some books and...

MY TWEETERS...

Close-up of the protective cap & tweeter

Along with my 18mm (sigh...they don't make it exactly 3/4") Baltic Birch

Dramatic angle shot showing all 13 plies

Brendan :rock:

 

[ezkcdude]

I wish I had your workspace! I built two pairs of speakers about 10 years ago, when I did have access to some equipment. One of the pair (shown below) has 1/4" baltic birch ply veneer on top of 3/4" MDF. They've been sitting in my parent's house for the last 10 years! (Every so often I have the desire to ship them out to my place, but they are like bricks.) Anyway, good luck with the project - make sure to spend time putting on a really good finish. If I recall, I used a combination of tung oil and polyurethane with hours and hours of hand sanding. Also, my advice to you is to make sure the edges match up nicely. You can see on my the edges are not quite flush. The finish is really nice, though, so it kind of makes up for it.

Focal Tioxid tweeter
Audax 8" Aerogel woofer (I believe these are not in production anymore, sadly)

 

[Nisbeth]

You do realize that with access to that kind of equipment you owe it to the rest of us to build something more advanced, right?

/U.

 

[Nebby]

Yes, that workspace isn't crappy at all! Access to heavy duty equipment = woot!

 

[cyberspyder]

Maybe next time, as this is my first speaker build, so I don't really want a hard design.

 

[Eagleboy]

Yeah man, that work space is beautiful. Those old Delta table saws are some seriously accurate machines. And those Delta Jointers last forever. Still have my Delta jointer, but I've since moved to a Saw Stop table saw. It's a lot nicer, but there's just no character to it. Which planer is that, for my curiosity?

So, good luck, and keep building and showing us the progress! I look forward to your speakers.

 

[cyberspyder]

A good old Wadkins Bursgreen.

 

[cyberspyder]

My Mini-RCA IC parts arrived (Canare Star-Quad, Switchcraft connectors)

Brendan

 

[cyberspyder]

IC done (Canare StarQuad, Switchcraft connectors), Mini-RCA:

Comments please!

Brendan

 

[infinitesymphony]

Is the thicker part just a tube for two runs of mini starquad? I've always wondered how people make such nice-looking Y-cables.