Arch Top Guitar Bridges

The bridge on your guitar is the most crucial link in the tone production chain between the power source (the strings)
 and the amplifier (the body).    The bridge is the conduit  through which the majority of the vibrations pass to set the 
soundboard in motion.  Its design and structure can dramatically affect the the tone, responsiveness, and the playability
 of the instrument.  Not surprisingly, there are many opinions about what is the best bridge design for a given guitar.  
For this reason, I spoke with several top arch top guitar builders to get their opinions on the subject: Steve Andersen
 (Andersenguitars.com.), Mark Campellone (Campelloneguitars.com), Bill Moll (Mollinst.com), and John Monteleone 
(Monteleone.net).

Tone always comes first in lutherie, so let's talk about how the bridge affects the tone.  As the transmitter of the
 vibrations, the mass of the bridge has the greatest influence on tone.  Mass is changed by the density of the material
 and the size of the material.  All the the luthiers I spoke with preferred to use ebony for its strength, color, and tonal
 properties.  The hardness of the material means a quick transferral of vibration to the top, as well as possessing the
 long term durability to support the stress of the strings.  Ebony provides great clarity in the high end according to
 John Monteleone.  He will sometimes use  rosewood, maple, or different species of ebony (Indian, Macassar, or 
African) that have varying hardnesses to adjust the voice of the instrument.  Maple has a much “fatter” sound than
 ebony, and rosewood has an “open and woodier” sound.  Tone being subjective, and all guitars being different, only
 your ideal as player matters.

All the luthiers preferred a one piece bridge base to a two foot model.  Bill Moll felt that the perfect fit of the base 
was ultimately the most important factor in bridge efficiency.  All the builders stressed the importance of hand fitting 
the base to the top.  Mark Campellone thought that the two foot model reduces the transmission of vibrations.  I prefer 
a full fit rosewood bridge on Gypsy style guitars to warm the overtones.

Steve Andersen will sometimes inlay the bridge top with a bar of graphite or steel to strengthen the less dense 
Macassar ebony, and has experimented using solid graphite or bone bridge tops on his mandolins to help brighten 
the tone and give them more “pop”.   I recently changed the saddle in one of my Gypsy guitars from ebony to bone 
and the tone change was dramatic.

Arch top guitars are very sensitive to humidity changes especially between summer and winter.  In the summer the
 top absorbs moisture and swells causing the arching and consequently the action ti rise.  When central heating comes
 on and the air dries out the wood shrinks and the action lowers.  Because of this seasonal change an adjustable height
 bridge is almost a necessity.  Bill Moll mills a solid aluminum post and wheel unit that threads into the base of the
 bridge to ensure energy is not lost through a loose fitting connection.  John Monteleone likes the solid connection that 
Jimmy D'Aquisto got with his bridge employing a tapered wedge to adjust the action, but was concerned that the
 bridge may be too heavy and restrict free movement.  The bases on D'Aquistos bridges were considerably wider 
than is traditionally used.

The bridge, I believe, can be looked at as an interpreter of the vibrations of the strings and can flavor the tone through
 its materials and structure to enhance or limit certain frequencies.  It is another tool in the luthiers arsenal to control
 both volume and overtone balance.  A harder material like ebony gives the guitar a quicker response, greater volume, 
and  favors a brighter tone.  A more resonant material like rosewood lends greater richness and a sweeter quality to
 the guitar. When setting up a guitar to suit a  players needs, the bridge design needs to be considered the strongest link

Bernie Lehmann
2004