Often times I am asked by customers what upgrades they can make to their guitars to improve the sound of their instrument. Most of the time, I advise them to replace their nut and saddle with one made from a bone material. This is a fairly low cost repair that is always an improvement. Most of the lower to mid-level instruments that are made today are fitted with a nut and saddle made from either injection molded plastic, or another synthetic material. Sound is a mechanical wave and travels by compression and rarefaction of the medium. Its velocity in an elastic medium is proportional to the square root of Tension in the medium. A higher density leads to more elasticity in the medium and hence the ease by which compression and rarefaction can take place. This way the velocity of sound increases by increase in density. Injection molded plastic soaks up some of the energy that is being used by your guitar to make sound. Bone is a denser medium and therefore transfers the energy more efficiently.
When customers have their plastic nut replaced with bone, they almost always can hear the difference in sound quality right away. The bone will give the instrument a brighter sound, and also increase its volume. The nut can be replaced on any guitar whether it is an acoustic or electric instrument. The bridge of an electric guitar differs from that of an acoustic in that they typically have individually adjustable saddles rather than a single saddle fitted in a slot at the bridge, and therefore do not usually have a saddle to replace with bone. On an acoustic guitar, however, replacing the saddle with bone is a good way to increase your energy transfer to your instrument’s soundboard. The soundboard, or belly of the lower bout of an acoustic guitar, serves as a speaker being driven by the energy of the vibrating strings. This energy is best transferred by a denser medium such as bone. The plastic that many companies use for their saddles acts to absorb a portion of your instrument’s sound transfer. Historically, nuts and saddles used to be made out of ivory, but with a series of embargos against ivory starting in 1973 and becoming international in 1989, it is now very rare to find ivory nuts and saddles on a guitar (if, by chance you own an instrument with ivory on it, it is important that you receive a permit from the international organization overseeing ivory, CITES (www.CITES.org) and need to submit some sort of documentation attesting to the age of the ivory to prove that it was harvested pre-embargo. Otherwise, you will never be allowed to travel with it across any international border). Now days, both bleached and unbleached ox bone is used more commonly in these upgrades, and are a huge improvement to the injection molded plastic that most mainstream companies often use.
By Dave Bolla
Certified Luthier
Grosse Pointe Music Academy Staff
To further complicate the issue of what materials are appropriate to use please read up on the current events involving Gibson and the Lacey Act: http://online.wsj.com/article/SB10001424053111904787404576530520471223268.html?fb_ref=wsj_share_FB&fb_source=home_oneline