Hardwood Floor|standing Speakers

Did you end up with a spare box of scrap hardwood flooring?
Make a set of floor standing speakers with it!

Skill level
Intermediate - advanced woodworking

Materials
Scrap hardwood
Speaker components.
Assorted wood screws - #6 or #8
Paint (optional)
Packaging foam
Wood glue
Liquid nails

Tools
Drill & bits
Router/jisaw
Tablesaw

Step 1: Layout Materials

Have your speakers ready to check sizing.
Match wood grains if possible.
Stagger the pieces to give the joints more strength.

Step 2: Glue Pieces Together

Using wood glue and clamps glue pieces together.
Set them aside to dry.
Stack them on a flat level surface.

Step 3: Remove Flooring Nails

If your scrap pieces have nails or screws now is the time to remove them now.

Step 4: Cut to Size

Cut all the pieces to size.
(Speaker components will vary, so measure twice cut once)

Step 5: Choose a Wood Joining Method

There are many types of wood joining techniques.
(http://www6.district125.k12.il.us/teched/Images/WoodJoints.gif)

I went with a dado wood joint.
It was the least time consuming, and stronger than a lap joint.

Apply the joints to the edges.

Step 6: Determine Speaker Configuration

Depending on the speaker components you buy, the manufacturer will suggest the layout.
Here I'm using a tmm setup. (Tweeter/Mid/Mid)

Step 7: Cutting Holes for Speaker Mounting

The easiest way to cut circles is with a plunge router and circle template.
I scored an open box plunge router for $30 bucks.
The circle template I had to make.

Pic1
Find a scrap piece of clear acrylic.
Copy hole set of the plastic base plate onto the scrap piece of acrylic.
Drill out holes.

Pic 2
Temporarily mount the template (Scrap acrylic piece) onto a working surface

Pic 3
Using a compass and a ruler, mark your lengths from the center point of the router.
(This will be the center of your router.)
Drill location holes at the marked length... this will be the pivoting/spinning point for the router

Pic 4
Mount the new acrylic template onto the router.

Pic 5
Cut a test piece.
The pivot/spinning hole rests in a screw placed in the center of your workpiece
As you are cutting all the way through, be sure to have scrap material to raise your piece so you don't cut into your bench

Step 8: Start Cutting the Speaker Holes

Cut the speaker holes out.

To achieve different depth cuts (set the depth gauge on your plunge router)

This allow for the speaker to sit flush with the surface. (PIC 2)

Step 9: Cut Speaker Input Hole

Cut out the hole for the speaker inputs in the back panel.

Step 10: Test Fitting

With everything cut out, it's time to assemble everything.

before gluing the pieces together, I like to do a quick test fit.
to see if the dado joints are right.

Step 11: Transmission Line Tunnel (OPTIONAL)

I decided to try a transmission line style of speaker.
This was done by creating series of internal baffles that reduce in size as it reaches the port at the bottom.

Read more about this type of speaker design here.
(http://en.wikipedia.org/wiki/Acoustic_transmission_line)

Pic 2
Use scrap angled cuts to reduce the amount of corners. (Enhances sound and increases structural rigidity)

Step 12: Ready for Paint.

I will be painting the front and back MDF panels black before mounting the speakers.

I have left the sides open to do all the wiring and stuffing.

Step 13: Mask & Paint (Optional)

Mask everything you don't want painted.

Lay down some paint.

Step 14: Baffling

Add foam/batting to provide baffling to eliminate standing waves.

Step 15:

Screw your speaker components in and run your wiring.

Using liquid nails, adhere the side panel.
(Rest it on the glued side, the weight of the speaker should provide plenty of pressure for a good bond)

Step 16: Finish Assembly.

Cut out some feet and mount them to the bottom.

Step 17: Speaker Covers

Pic 1
Using some 3/4"x3/4" scrap lengths and circular router offcuts.

Pic 2
Create the speaker cover frame using glue and nails.

Pic 3
The circular router off cuts provide the strength.

Wrap the cover with some acoustic fabric.

And... Done.

Comments

[MAHESAN]

[LordRussell]

My only problem with Trans Line assemblies is if done 'wrong' will rob your cabinets of their low end frequencies faster than a starved lioness fires through a bucket of fattened hamsters.

Your design here is elegant as well as functional, but you're not immediately showing the 1/2 to 1/4 rule in your step down (or the basic 'angular' thought) behind the Trans Line construction. Your measurements seem to follow the guidelines, but I was always led to believe the construction was to be at some kind of angle.

Hey, that's what thinking 'out of the box' is all about right?

[tubegeek]

Certainly there are many places on the net to discuss and learn about subjects like speaker volume, T-line length, stuffing, crossovers etc. What I found VERY unique and valuable about this 'ible is that the fairly straightforward construction method results in such a good-looking enclosure. For me, I would do this process AFTER I had developed a design that I had decided was worth boxing up nicely. I am very glad to see how hells-oui did it. This is a very good home-workshop-style alternative to more typical methods like birch ply & stain, or MDF & veneer, with a similarly attractive result and, I think, more options for fancy wood choice and colors. Let's face it, putting down a good durable finish is difficult and time-consuming, that's the whole reason pre-finished flooring exists.

I wouldn't worry at all about the hardwood being resonant in this design, note that both front & back walls are MDF, and note that the T-line parts will VERY securely brace the hardwood sides.

Excellent 'ible providing MUCH food for thought, thank you very much hells-oui.

[danzo321]

I think you could have laid muslin over the attic speakers to keep dust out, then used fiberglass batts for insulation. Air could move semi-freely enough to take advantage of the 'infinite' attic box. I have 15" Jensen woofers in 11 cu. ft. 'boxes' which are sealed-off parts of attic and wall cavities. They sound gorgeous.
I realize, our friend Hells-oui is showing how to build a very good looking box with ingenious quickie folded horn, not leading a class in speaker design.

[hogey74]

Nice article thanks! I've got some old monitors that sound great but the particle board is particle-izing ... ur giving me ideas :-)

[danzo321]

SMART to use this heavy flooring which has a supertough finish already. But first step ought to be: design the speaker boxes.

[danzo321]

Ideally this design features a constantly tapering cross section [folded horn] which will drive you nuts with the angles! But just note the two woofers are not equally spaced from the gap, so right there you have a slight time differential. In other words: the 2 woofers move up + down in unison but face unequal box pressure.

[danzo321]

Veryken is right, the internal volume has to agree with the suspension stiffness and size of the speaker cone. As it travels from farthest down to farthest up it moves a measurable qty of air and the air in the box acts as a spring. Speaker manufacturers should give this measurement as "Q" and there are formulas to use. Ported enclosures have their own formulas.
With an open attic as your box, you have what is called an infinite baffle, and must use a really stiff woofer.

[Tom Hargrave]

Bose has made a small fortune by perfecting this type of technology in their "acoustic waveguide" technology speakers. We need more innovators in this world.

[veryken]

Looks great! Aside from the "acoustic transmission line" that you mention, what determines the box size? I thought speaker design was all about the internal volume -- width, depth, resonant surfaces, even solidity. I'm not criticizing, but I did a similar box mount for a ceiling situation with an open attic. The sound that resulted were not that good.

[bigdawgte]

did you use any formula/calculator, etc. to design your transmission line? Or did you just wing it?

[Boost]

They are really nice looking! How do they sound?

I would be afraid that solid wood would make it a resonance box giving it a "boxy" sound. I have always strived to get a dead box (as in non vibrating and sound conducting) in my speaker cabinets.

[hells-oui]

Thanks!
They're not too bad, no boxy sound.
The hardwood was santos mahogany.
It has a density similar to mdf.
So I thought... why not.