I've been experimenting with some new banjo bridge designs that follow the theory that to get more even string response, there should be either no direct path for string vibrations through the bridge to the head for any of the strings, or there should be an equal number of paths for each string. The standard three footed bridge does not meet this criteria. I made 4 new designs (well, 5, but one broke as I tuned the strings up to pitch...) and one fairly standard three footed design (although there is quite a bit of variation out there just among that design).
The first photo is the drawings for them. I'll call them numbers 1 through 5 starting at the top. The second photo shows the actual bridges.
Here are the results that I found on my banjo.
The top left design in the photo (2.0 grams) has three feet and no direct path to the head for any string. It had a very bright and open sound and even string response.
The bottom right design (1.7 grams) has 6 feet and 2 paths to the head for each string. It had an incredibly bright, crisp sound, even more so than number 1 and 3. It was loud, open and even.
The bottom left design (2.0 grams), which I had great fun adding a bit of chip-carving to, has seven feet and 2 paths to the head for each string. One of the biggest surprises of this test was that this bridge and #1 sounded all but identical. This also had very even response and a very bright, open sound. The designs are so radically different, that I am not quite sure how that happened, but it did. I am curious to see if that holds true on other banjos, a test that will have to be for another time. Anyone have ideas why this might be?
The top right design in the photo (2.0 grams) has four feet and no direct path to the head. It had probably the most even string response of those tested. Its brightness fell in-between that of the standard design and top left design. Mild, pleasant tone. Not as bright or open as I would like, but still an improvement over the three foot bridge.
The standard bridge (2.0 grams), as expected, had an uneven response. It was heavy on the bass response with a muted tone on the treble strings.
I can't quite decide which is my favorite, but I lean towards #2, most of the time until the brightness (especially when played with fingerpicks) is just too much, then I prefer #1 or 3.
Thoughts?
I may try to get some sound files for these soon. Any interest in hearing them?