Bridge density, thickness, and height (a eureka moment!?)

[Greg Adams]

Hello everyone,

As you know, I am not a builder (though I am a documenter of banjos), but I do play early banjo music. With this, I have a strong tendency to perpetually tinker with setup (bridges, nuts, strings, and head tension), usually making things worse. Yet, I don't give up. I do this because I am working to get the ideal sound from my mind's ear onto the instrument. After many years of tinkering with early banjo music and my reproduction instruments, I finally feel like I am onto something that aligns with my aural vision and reflects my personal tastes. I thought I'd share what I've learned (though others have probably come to these conclusions and I will demonstrate my skills as Master of the Obvious).

Well, I feel as though I have established very good consistent head tension on my Hartel Ashborn. I took off the wonderful rosewood nut Jim built (so I wouldn't screw it up) and replaced it with a piece of scrap. With this scrap I have filed grooves so that the strings are literally resting a paper's thickness above the fingerboard.

From there, I took one of the bridges that George Wunderlich built for me (an incredibly dense, but extraordinarily light piece of maple, I believe) and, with my trusty piece of sandpaper, sanded the bridge thickness so that it is quite thin at the top (as thick as a quarter) and increasingly thick towards the feet (I'm not at home or I'd measure it exactly and report the measurements at the feet and the top). THEN, and this is where it gets meaningful for me, I began slowly sanding down the bridge height.

Every 5-7 careful swipes of the sandpaper, incrementally shortening the height of the bridge, I replaced the bridge to its 28 inch scale length position on the head of the banjo (which is tuned dGDF#A). Then at the 10th and 12th position on the first string, I began to press the string down, NOT to the fingerboard, but to the point where I could hear the overtone series of the note, usually just above the fingerboard. I identified this point as the most important point of responsiveness when pressing down the string. From here, I continued to incrementally sand down the height of the bridge until the slightly depressed string, my desired perception of the overtone series (what I call "the point of greatest responsiveness"), and the fingerboard met at a single junction.

I must say that I am REALLY pleased with how things are coming together. For example, reaching the 12th-15th positions, where some of this early banjo repertoire goes, is much more forgiving. At first I was concerned with the bridge being too short and my finger and thumb annoyingly hitting the head of the banjo. HOWEVER, I feel as though, since I've maximized the sweet spot of each semitone on the fingerboard, I don't have to hit it as hard and am, thus, improving my own economy of motion.

I'll keep monitoring these results to see if my claims are warranted. Ultimately, I feel as though I have experientially come to appreciate a deeper perspective with the early banjo (and banjo setup, in general) and wanted to share my enthusiasm (however parochial my insight may actually be to those who are builders and have a stronger grasp of the physics of sound).

Best to you all,
Greg

[Trapdoor2]

Great stuff, Greg (and Dan'l). I would add that bridge experimentation is a slippery slope to perdition. Next thing you know, you'll be wondering if that tailpiece couldn't bear just a bit of adjustment to add some downforce to the bridge...and then you'll wonder if fishing line can be substituted for gut...and then...well, it is only a hop, skip and jump to a Masterclone! ;-)

A few years back, I attended "Nashcamp" and took a class on "banjo adjustments" from Ned Luberecki (top-drawer BG player and Sirius Radio BG host). When we got to bridges, he produced a nylon-zippered bag about the size of a men's shaving kit. It was absolutely stuffed with "Snuffy Smith" bridges. He claimed to be able to hear the difference in tone (one bridge to another) so acutely that he often changed bridges between sets. A tad OCD if you ask me!

If you want to start a quick flame war, go onto the Banjohangout and claim you've discovered the best bridge (but you must assert that all others are pitiful imitations, not worthy,etc., etc.).

I think we called the multi-footed bridge a "Minstrel" bridge simply out of ignorance. I called 'em "Morris" style bridges for a couple of years...until I found that they were just made by a Mr. Morris. Today they're typically sold as "Cole Style" bridges though the 'minstrel' moniker is still around.

[Joel Hooks]

http://www.google.com/patents/about?id=yFcXAAAAEBAJ&dq

I don't think that old Joe would have been able to buy one.

[Rob Morrison]

Greg and others--

I made a discovery this weekend I thought I might share with you all. To do so I'm reviving this thread from a little over a year ago. It concerns the appropriate bridge for these clunky, yet somehow beautiful instruments we all play. This is probably more of a problem for me than most others, as I get the impression that most folks play the amazing new reproduction instruments which come with suitably appropriate bridges. All my banjos have spent several weeks or months or years in my Dr. Frankenstein's laboratory where I bring them back to life. I have never, to date, had one show up with an original bridge. I've also never found an affordable commercial source for the "right" bridges for these instruments. As has been previously noted, bridges advertized to be "minstrel banjo bridges" are more properly referred to as classic banjo bridges.

I have tried various strategies over the years. I have made my own bridges with varying degrees of success. These are very time consuming and labor intensive. I have tried an old S. S. Stewart bridge (the kind that looks like a railroad trestle), but I didn't think it sounded very good. I usually have ended up with a simple, straight modern bridge. And yet I always hated the way it looked--anachronistic and esthetically unpleasing.

Today I was looking through my banjo parts to see if I had any two-footed bridges, and I found an old Grover Non-Tip bridge which is basically a two footed bridge with a cross support in the middle. These bridges have been around forever, but I don't ever remember seeing one on a banjo before. They are narrower than conventional bridges (1 and 7/8 inches versus 2 and 1/2 inches) and the spacing is somewhat narrower. Anyway, a light bulb went off over my head and I removed the cross support and put it on my old clunker.

I was dubious due to the narrow spacing and my previous lack of success with the narrow S. S. Stewart bridge. To my compete amazement this bridge outperformed the modern bridge by a mile. It was much louder, clearer, and easier to play. I think the ease of playing was due to the narrower spacing. This surprised me as much as anything , and is likely to be a matter of personal preference.

The cross support can be removed by just pulling it out. I filled in the slight gap left by the removal by whittling a piece from a popsicle stick and gluing it in the gap and sanding. This step is strictly for cosmetic reasons.

You may be thinking to yourself, "How am I supposed to find a Grover Non-Tip bridge, anyway'? Well there must be an over-stocked warehouse somewhere with about a billion of these things, because they are still available through the Elderly Instruments catalogue in either 1/2 inch or 5/8 inch heights. And they're cheap.

[Dave Culgan]

That's what I've been using for a while on one of mine. I was thinking of changing it out, more from it being an anachronism ( I need dance around that tune) than any issues with tone. Now maybe I'll just leave it be. Dave Culgan

[Rob Morrison]

Dave-

Thanks for the feedback. This just goes to show how hard it is come up with an original idea. As far as the anachronistic qualities of Grover Non-Tip bridges go, I'm actually quite pleased with the appearance. The Grovers look a lot like bridges in the old photographs, many of which were narrower than modern bridges and were two-footers. Rob

[Ian Bell]

I tried a bunch of things on the tackhead I made this summer. I started with the very hard maple I'd used for the neck, and a few other things that were lying around the shop but settled on a three-footed bridge made out of some thin basswood I had left over from a ship model project. I made all the bridges pretty thin and more or less the same. For some reason the not-so-dense basswood seemed to transmit to the rest of the instrument best. I couldn't tell you why. (not a very scientific posting)

[Rob Morrison]

One further development in my experimentations with Grover Non-Tip bridges.

One of my fixer-uppers is a "store tub" from the Pollman instrument catalog. These banjos were simple bare-bones affairs made of inexpensive wood, were very light weight, but, nonetheless, had handsome brass eagle brackets. Looks good, sounds bad. They cost about a $1.50 apiece. Tweak as I may, I was never able to get this banjo to sound worth a darn, and I tried everything I could think of. Tonight I installed a Grover Non-Tip bridge (minus the cross-Piece) and voila!--it sounded pretty good. Not great, but a whole lot better than the lousy sound it had put out. The lesson for me here is not necessarily that old-style Grover bridges are somehow miraculous, but simply that the ideal bridges for these instruments are something similar to the Grovers. I am becoming a firm believer in the general superiority of simple two-foot bridges for these instruments. I wish I could have figured this out a long time ago, but better late than never.