[Harp-L] Light Boxes for Embossing

Some thoughts on light boxes:

- I've tried every way of embossing reeds including microscopes, and my
personal favorite method is back lighting with a light box that allows you
to plink the reed as you work. When you have a slot set up over a
resonating chamber with a light source that you can control with a dimmer
switch, you have complete control over instant audio and visual feedback as
you work. The box amplifies the sound of the reed as you plink it - its
like a kalimba... and you hear variations of sound that you are creating as
you emboss.

One of the problems of embossing is that if you go too far, you start
creating what I call the "kazoo effect". You get these weird treble vibes.
Compare the tone of a heavily embossed harp with a harp that has not been
embossed. The stock harp has a more round tone with more presence in the
bass end of the overtones.

I went through a phase of seeing how close I could emboss, and ended up
throwing away a few harps that sounded like kazoos and then just sounded
lifeless when I started scraping away the excess.

The trick is to do enough embossing to improve compression without getting
too far into the treble range of overtones.

The other thing is that the way you shape the reed is more important for
overall response and tone than embossing. Embossing is the icing on the
cake. It will only partially compensate for a reed that is poorly shaped.

So embossing improves compression, but it also changes the sound.
Microscopes emphasize visual feedback. A light box can give you both visual
and audio feedback as you work so you quit before you go too far.

When you manipulate back lighting, you can visually emphasize the gap you
are working on as much or little as you want.  a dimmer switch helps you to
balance out your back-lighting with the ambient lighting in the room.

I have developed light box designs that also give you ways to monitor if
your eye is drifting left to right - this alone makes a big difference in
how you perceive the gap as you work. And a design that lets you change the
angle of the work surface to the ideal angle.

Plus a new embossing / burnishing tool that lets you get to the very end of
the slot while holding the tool like a pen.

The result of this system is a way of closing slots that lets you stay
relaxed while you work and gives you moment to moment visual and audio

You can find pictures, blog posts, and videos at:


here are sketches of the basic idea for the ultimate light box:


here is a light box that was built by a shop class in Erie PA:


There you go!

I'm closing in on building light boxes with the best of all the ideas I
have. But you are free to use the ideas I have posted - let me know what
works for you, I am always interested in new ideas....

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