Replies to This Discussion

Permalink Reply by Ron "Oily" Sprague on December 20, 2014 at 2:12pm

You can build them from plywood. And as a physicist / teacher of physics, you know they will work, if they are constructed correctly. But they are normally built from hardwoods, typically traditional tonewoods like maple, spruce, cedar and mahogany. As a physicist / teacher of physics, you know why hardwoods should work better.

The ones in your link are built from either fir or maple. It's really the size and wall thickness of the boxes that are important, not necessarily the material. You could even do the resonance experiment using different lengths and thicknesses of PVC pipe. Wine glasses filled with water, or empty soft drink or beer bottles, are classic resonance boxes, too.


And this was a Kewl high school physics link:
http://kellerphysics.com/acoustics/Lapp.pdf

• ▶ Reply

Permalink Reply by gary herget on December 20, 2014 at 2:16pm

The boxes pictured appear to be a laminated material. You can buy buy birch laminate at most big box, hardware stores. Birch is a good sound wood. As for dimensions it's hard to estimate, you could maybe figure something out using the dimension of the fork in comparison to the box. Not alot to go on but might get you started.

• ▶ Reply

Permalink Reply by Primitive Acoustics on December 20, 2014 at 2:48pm

When I Googled resonance boxes and tuning forks I was amazed at how much information was available on this experiment.  I would go with the Baltic Birch plywood from the local craft store for $5.00.

• ▶ Reply

Permalink Reply by Ron "Oily" Sprague on December 21, 2014 at 1:32pm

Baltic birch is good. Old Harmony gits were made from it, and many high end speaker and amp cabinets use it.

• ▶ Reply

Permalink Reply by DavidKent on December 21, 2014 at 2:46pm

Thanks Ron.  I bought some today.  Now, the trick is to make a square (right angle), reasonably strong box with my rather limited carpentry skills.

• ▶ Reply

Permalink Reply by Ron "Oily" Sprague on December 21, 2014 at 4:34pm

David,

With patience and a coping saw, you can make finger jointed boxes. Or you can just butt join them by gluing them together, using a right angle square and a rubber band. There are also right angle and 4-corner strap clamps available at Lowes and Home Depot that can get you, ahem, squared away.

• ▶ Reply

Permalink Reply by Ron "Oily" Sprague on December 21, 2014 at 1:33pm

Cardboard boxes don't work too well, though ;-) they do work, but wood resonates better.

• ▶ Reply

Permalink Reply by DavidKent on December 21, 2014 at 2:51pm

One trick I do in my Physics class is with a slinky and empty, open topped cardboard boxes of different sizes.  If you shake a slinky back and forth, you'll hear some sound, but not much.  Then, if you hang one end of the slinky over one side of a box (wedge the vertical side between the coils a half inch or so from the slinky end) guess what you'll get?  The sound of the blasters from star Wars.  I swear that they must have done this with a small box to create that sound!

So, cardboard works for that application.

• ▶ Reply

Permalink Reply by Ron "Oily" Sprague on December 21, 2014 at 4:31pm

Yeah, you can also get a good tube wave going out of a Pringles can, ;-)

Oh, and here's how the blaster sound was created:

http://en.m.wikipedia.org/wiki/Blaster_(Star_Wars)

• ▶ Reply