A while back, I became interested in finding a solution to the "Floppy G String"
problem. Because most Irish tenor banjo players follow the
dictum of Barney McKenna and play the GDAE octave tuning, many banjos
end up with a flabby toneless G string while the rest of the
strings can sound good. For the most part this is not a
problem as long as you play tunes written for the whistle (which only
goes to low D) but if you want to play fiddle tunes or use the G string
as a drone, it just doesn't work.
Part of the problem can be due to poor selection of string gages.
D'Addario sells its J-63i set which only goes to a .036 inch
G string. Most 19 fret banjos don't sound good until at least
an .040 inch G string is used and 17 fret banjos usually need at least
a .042 inch G string. Even then there is still an inequality
in both volume and quality of tone on some banjos.
One of the reasons for this is that tenor banjos were designed with
cgda tuning in mind. These banjos needed to be loud and
treble to cut through the rest of the band. They were used as
rhythm instruments with some solo capability. While they
could be played single string style, most of the time they were not.
In contrast, Irish Tenor banjos play an octave lower and are melody
instruments. The G string is tuned far below the scale of a
jazz tenor.
But tenor banjos can be made to play well in the GDAE range.
Mostly it is a matter of setup. I found that if
you add a moderately heavy head such as the Five Star from Stew-Mac or the Renaissance
head from Remo and tune the head to a sound that you like,
you could help the sound. Changing strings to a heavier gage
and/or to nickel also helped, but the most important thing that worked
for me was changing the bridge.
I bought a number of bridges including several from Mike Smith of Kateyz who
put a lot of work into finding a good bridge for me. I was
satisfied with this purchase, but only one banjo did well with this
bridge and I decided to find out a little more about bridges and the
Irish tenor banjo.
I started with several premises based on an idea from Red Henry,
the mandolinist who went on a similar search for a better mandolin
bridge. He sent me a few experimental banjo bridges that he
had made from the same maple that he makes his mandolin bridges.
He found that he got a better tone with bluegrass banjos if
the bridge was longer than the standard 7 cm. His bridges
were 9 cm long and they seem to have a more complex tone. My
theory is that the bridge was imparting energy to the head at different
points than the standard three foot bridge and that the harmonics that
formed were producing a better sound. One of the
clues I had came from jazz banjo players who often preferred the two
foot sound. The original banjo bridges were two footed; the
third foot came in to counteract the sag that occurred after the two
foot bridges were stressed for a while. Three foot bridges
not only had the energy points closer together, their footprint was
much larger.
This latter point is important because the larger the footprint, the
less energy per square centimeter was imparted and more chance for the
energy to be dissipated before it was turned into sound by the head
vibrating. So the first premise that I worked with was that
the bridge had to have a wider distribution of entry points (hence the
width) and that it had to have a smaller footprint so the energy would
be more concentrated.
The second premise concerned the material that bridges are made from.
Bluegrass banjos use hard maple and (usually) ebony as
standard bridge material. Lately some of the premier bridge
makers have been experimenting with other top and body materials
including purpleheart and Honduran rosewood for the tops plus birch and
wood that has been under Lake Superior for many years (causing a
cellular change) for the bodies. More adventurous makers such
as Bart Veerman
of Canada have branched out using tropical woods like teak for the body
and finding hard woods from Africa, Asia, and Central/South America for
both tops and bodies. The result has been a large body of
knowledge on how these woods change the sound and how combinations can
tailor the sound to your needs. I felt that a change from the
traditional ebony/maple mix might help.
What has been especially gratifying is the open generosity of the
premier bridge makers on the Builders Forum of Banjohangout.org
including Bart Veerman, Silvio
Ferretti, Scott
Zimmerman, Mike Smith and a host of others who are free with
their information and have added to my knowledge of bridges immensely.
Not only do they characterize how various woods sound, but
they all said that the mass of the bridge was an important factor as
far as the quality of the sound and volume goes.
The third idea that I had was that the sound of the string has to
travel an indirect rout to the head in order for the bridge to filter
the signal and produce the signature sound of the bridge. If
you look at a violin bridge you are struck by several things: the
bridge is perpendicular to the body of the violin in the rear, but
slanted slightly in the front. Also it has all sorts of holes
and curly-cues in it that make sure that there is no straight line from
the strings to the body. In addition, the footprint is very
small compared to the mass of the bridge. The sound has to go
around and about before it is channeled into the violin.
Initially I decided to put a 1/4 inch hole beneath each string.
The idea was to make sure that the vibrations would
take an indirect route assuring that a filtering
process would occur. Bart Veerman wrote me and told me that
the holes were not needed as the sound would be filtered by the type of
wood and the construction of the bridge. I tried a bridge
without the holes (except for the half hole in the middle at the bottom
of the bridge) and achieved a pretty good sound. I am still
uncertain if these bridges will do better with or without holes.
I suspect that each banjo will dictate whether this
design feature will help.
I started out with a number of design ideas, mostly random, based on
the standard bridge. Red's bridge was a two footer which
separated the entry points, but had the disadvantage of sagging after a
while from the pressure of the springs. There were several
fixes for this problem, one being a more substantial span between the
two feet, but I decided to go with a central post configuration after
trying several solutions. The difference would be that the
central post (actually two separated by the half hole) would have a
minimal footprint. This allowed the stress of the strings to
be supported in the middle without a large kludgy foot.
I tried a "square" bridge with nearly perpendicular sides, but the
width of the bridge interfered with my right hand which is used close
to the bridge most of the time. The solution was to have
sloping sides that reached out like an outrigger. While the
bridge was 9 cm. wide, the bearing surface was only about 5 cm wide
which would allow plenty of room for strings without interfering with
right hand technique. Once the edges were smoothed out, any
contact with the bridge was comfortable. I used a 36 mm
spread (1.2cm between strings) which is a little wider than normal, but
suited my style and my banjos. All sharp edges were rounded
including the ends of the bearing surface for comfort.
The bridge designed was basically form following function.
But in this case, the premises were different from the
standard bridge due to the special needs of the Irish tenor banjo.
As a result, the bridge is different in shape and it has a
different effect on the sound of the banjo. This bridge is,
for lack of a better word, "swoopy" and resembles a 1950's flying
saucer or perhaps a spider. Granted, you need a lot of
imagination to make that claim, but why not?
The next step after standardizing both the design and the manufacturing
process was to try out different wood combinations. I
enlisted the help of several Irish banjo players and started sending
various wood combinations and design variations. I also
tested them on my own banjos which include an FQMS MasterClone that I
made, a Vega Little Wonder (17 fret), a B&D Silver Bell #1 (17
fret), a Leedy Frankenbanjo with a Rettenburg neck made of Brazilian
Rosewood grafted on it 70 years ago, and several ebay specials made by
Slingerland. As expected, I found that each banjo responded
differently to the various combinations and that some worked better
than others on each banjo. I compared the tones and the
responses to the standard Grover bridges that I had on each banjo and
found that the design was better for the most part.
In broad terms, two things made a difference: the weight of the bridge
and the materials that they were made out of. The height of
the bridge did have some effect on volume and playability but the style
used in Irish tenor banjo is a single string plectrum style and it is
very forgiving of height while any deficit in volume could be made up
fairly easily with the plectrum.
This was not unexpected as the Bluegrass bridge luthiers have known
this for years. A bridge that is too heavy can dull down the
sound of a bluegrass banjo while one that is too light can be
annoyingly harsh and strident. All agree that there is a
range of weight, usually described as about 1.7 grams to 2.3 grams that
seem to work well depending on the individual instrument and the
expectation of the player. The latter issue is important in
the bluegrass world because everyone wants their banjo to sound "like
Earl's" even though that sound is elusive.
Irish tenor players, for the most part, don't have an archetypal sound
in mind, but they do want a pleasant complex sound from their banjos.
That sound may be the bluegrass sound, but for the most part
it is whatever the banjo can produce at its best. Since most
tenor banjos are not flat head Gibsons and since there is that nasty
"floppy G" to worry about, the "sound" that is best is an individual
thing. In general, most players want a decent sounding G
string whose volume and tonal clarity is similar to the E string.
In addition the total sound has to be pleasing to the ear
without a thin strident sound that you often hear when an attempt is
made to make the G string sound good. (A good example of this is the CD
that accompanies the Dublin
Banjos instructional book. Part of the problem is
the recording technique but both of the banjos are so strident that you
can only listen to the music for a short time. It doesn't
help that Sully plays a banjo-mandolin on one cut and that John
Keenan's banjo is slightly out of tune compared to Sully's.
But the playing is magnificent if you can get past the sound
- which reminds me of sticking knitting needles in your ear.) My
expectation was that the optimal weight range for the Irish tenor banjo
would be a little higher than that for bluegrass banjos.
So far my experiments have shown that a weight range of 1.8 grams to
2.4 grams seems to be best. Granted, this is not much more
than the bluegrass range, but on my banjos, at least, the higher end of
the range works well. One of the reasons is that the
materials used for the bodies of my more successful bridges have been
from woods that are not as bright sounding as hard maple (such as teak
and canary wood) and they are a little more dense. In order
to make a stable bridge, it will have to be heavier for the same
dimensions. If I go below or above the range mentioned, the
sound suffers, no matter what the materials are.
The sound differences are obvious, sometimes striking (I will insert
mp3 comparisons here some day), between bridges of the same approximate
weight but different materials. They are also different
between two bridges of the same materials but different weights
although unless you go to high or too low on the weights, they tend to
sound about the same. Footprint size also makes a difference
and a footprint with twice the area sounds significantly less pleasing
than one with a small footprint.
For now, I have settled on four body woods and five different top
woods to experiment (for those of you who are not math majors, that
is 15 combinations plus three all body bridges for a total of
18 possible bridge types.) I narrowed my choices down to only
a few of the combinations for now but have had some success,
nonetheless.
Here are descriptions of the bridges and a small comment on
the effects of each combination:
1) Purpleheart
and Maple (PH/M)
This was the first combination that I tried mostly because that is what
I had on hand. This is a combination that has been tried on
bluegrass banjos because of its tendency to add brightness. I
made bridges in the 1.7 gram to 2.33 gram range in all sizes.
The result was a louder banjo with brilliant highs that were
annoying in session if the bridge was at the lower end of the weight
scale. Good friends moved away from me when I brought it to
the session. The one in the picture is an "asymmetric" bridge which was an experiment to see if the G string would be enhanced. It wasn't.
This combination had a lot of "pop" that made it suitable for the cgda
tuning and I sent a few to Vin
Mondello who is a well known tenor banjo luthier and maker.
He told me that they worked best on his instruments of the
tops were thinned down and the bridge lightened. PH/M will
brighten up a dull sounding banjo and make any banjo a little louder.
2) Purpleheart
and Sapele (PH/Sap)
Sapele is a mahogany like wood found in Africa which is easy
to work with and has a tendency to be more mellow. I added
the purpleheart to give the sound a little snap at the high end while
keeping the G string both equal and mellow. When the weights
are in the 2.0 g-2.3 g. range this combination seems to work well on my
MasterClone. Any lighter and it loses the distinctive sound
and any heavier it dulls down.
3) Ebony and Canary Wood
(E/CW)
Bart Veerman suggested using ebony and teak, a combination that he has
been very successful with, but I could not find any teak when I started
(I have some now) and used some canary wood instead. Canary
wood is an attractive yellow wood that is close to teak in weight that
grows in South and Central America. The E/CW combination has
more high end power but still has a lot of mid-range. It
enhances the G string and the E string is more powerful than the PH/Sap
combination.
4) Bocote and Maple (B/M)
Bocote is another New world tropical wood that seems to act like ebony
except that it is much more mid-range. The banjo pops all the
way down to the G string and currently it is the bridge I am using on
my MasterClone. The maple I am using is a little softer than
the maple in the PH/M bridge and this is probably one of the reasons
that this bridge is so balanced.
5) Pink Ivory and Maple (PI/M)
Pink Ivory is a "rare" wood (meaning expensive) that, as far as I can
determine, is not used in banjo bridges. I have had one
reviewer rave about this combination on his Vega. He stated
that it "really brought out the G string and blew me away."
My experience has not been that impressive but I will make up
a 1.88 gram bridge and try it out in the near future. So far, this bridge has been a surprise. As far as I can tell, no one has used pink ivory before. It was only my ignorance and a really good deal on the wood that got me to try it.
Added Information: Several reviewers now praise this combination all of whom were playing vintage Vega or B&D banjos. There may be something to this with the older banjos, at least.
6) Ebony and Teak (E/T)
Ebony and teak is a long time favorite of Bart Veerman who pioneered this combination. It does all that he says it does, crisp highs and mids, and articulate lows. I love this combination and it is available right now here. Just ask Bart to make one for tenor banjo in the 36 mm spacing.
7) All Maple (M)
Maple is a good wood on its own. It has a tendency to amplify all the strings and it sounds great on a lot of banjos. Good hard maple will hold the strings without being sliced as will other hard woods such as apple and yew. Several of my testers like the all maple bridge and you can find a number of bridge makers who sell them. If that all maple look bothers you, take a magic marker and paint the top strip black.
8) African Blackwood and Lauro Preto (AB/LP)
Lauro what? I never heard of it either, but this is a very nice combination with lots of mid-range, a listenable high and decent lows. The wood is really nice to work with and it glues and machines well. My local hardwood store has a few more boards at a price I can't pass up. The wood is gray/purple and moderately dense. It is sort of teak-light, for a lot less money you get a similar sound.
9) African Blackwood and Brazilian Rosewood (AB/BR)
Yes, I found some Brazilian Rosewood at a local store. Don't ask, I don't know where they got it as such a cheap price. The AH/BR combination is also very mid-range although a little more high end than AH/LP. I kind of hate to use such beautiful wood on a banjo bridge, but it has a lot of postitive qualities, especially if your banjo tends to be treble that way mine is.
10) Others
I have a number of experimental combinations out there and am trying to
see what will work. One interesting
wood is yew which was sent to me by Red Henry. Yew is known
as a good wood to make bows with and it is dense but light. I
made an all yew bridge that sounded very good and am in the midst of
making an ebony/yew bridge. I only have a few blanks but will
try and find some more yew on ebay.
I made a few bridges from Alaskan Cedar. This wood
is very strong for its weight and it seems to be acoustically neutral.
It tends to translate the sound of the top only which is an
interesting thing on its own.
Another top wood that I am using is Honduran Rosewood which is another
dense tropical wood that has musical qualities. I have not
made enough bridges to determine wha it can do, but it is very similar
to ebony.
I now have some Bolivian Rosewood which is also known as purple ebony. It has an interesting sound when combined with maple.
On order is persimmon. I also have makare, snakewood, greenheart, and several woods I never heard of such as birdseed. Keep watching this space.
7) Applicability to 5-String Banjos
So far, any attempt to make a better bluegrass banjo bridge with this design has not been as successful as I want it to be. Many of the bridges that I made were better than the standard bridges on the GDAE tuned tenor. My experimental numbers are small, however (n=1, a 1925 Gibson BB conversion) and I have only made a few 5-string bridges.
For one thing, I am trying to achieve the opposite of what a bluegrass banjo players wants. I am looking for an equalization of sound and more definable bass while keeping the E string legal under international law. If any 5-string will benefit it will be the clawhammer style since they are looking for a "plunky" sound and some of the Vega conversions might be very bright, especially those with Tubaphone rings.
Added Content: But good news, I have sent a few Purpleheart/Sapele bridges to clawhammer players and they seem to like them.
Here are mp3s of Steve Srubas playing Shoes and Stockings and Greasy coat using one of the bridges.
Final Word
So far the experiments have been very encouraging. My
assumptions, for the most part, have been born out. The nine
centimeter span does have a different (and to me pleasant) sound that
is at least as good as the standard design if not better. I
have tried this design on a number of banjos and have also farmed it
out to others who have been critical (in the good sense)
and very helpful. I think that this design has a
lot of potential but the jury is still out. After all, if you
make a hundred bridges you are bound to find a few that are really good
no matter what you do.
Each wood seems to have an optimimal perfomance weight (although the thickness of the top and the type of top makes a difference) which is often surprisingly narrow although most of the woods are somewhat forgiving. I did find that you can make a banjo strident with almost any wood as long as you make the bridge light enough. There are some restrictions due to design, make it light enough and the outrigger legs break when moving the bridge under stress, but for the most part getting to the optimal weight is doable with all the woods, including the dense tropical body woods such as teak and canary wood. A more precise table of weights is in the making.
Another factor is that each bridge is different from others of the same general construction and materials. Part of this is due to variation in manufacture, which is almost entirely by hand and subject to variation, but also due to the nature of wood which is not a uniform material. If we could use graphite, we would, but the advantage of wood is the variability which allows for genius at times. The moral of the story is that you have to try out several bridges to find the sound you want, you can't just order it up.
A surprising find was that the "sweet spot", the area on the banjo head in which the best sounds are available, is extended and in some cases extend to the fingerboard. Vin Mondello told me that this was true with the cgda tuned tenor also.
I am not going into the business of making bridges, there are others
who are far better than I am at it. I do want to find out
more about what makes the GDAE tuning tick and I think I have found a
way to enhance that tuning with a bridge that responds across the wide
range that the GDAE tuning brings.
Stay tuned.
Update #1
I have a lot more experience with these bridges now. They seem to be better than the cheap Grovers, which is good considering that they take a little bit of time to make. The primary qualities seem to be clarity and a larger sweet spot. The materiels do make a big difference. My Leedy only seems to be terrific with the African Blackwood/Teak combination.
I have made a number of Purpleheart/Maple bridges for Jazz tenor and plectrum players, thanks to the efforts of Vin Mondello, and find that a thin top makes them sound best. My Ebony/Maple bridges were universally ignored. I was able to be successful in a variety of sizes down to 3/8" (!) which I have on my B&D Silver Bell #1 17 fret instrument.
Each instrument seems to have specific needs. There are times when my bridges don't enhance the sound as well as another style or type of bridge. That's why I want people to try the bridges first before taking them.
