A STUDY ON TIMBRE ADJUSTMENT OF ELECTRIC GUITAR BASED ON VIBRATION CONTROL OF PICKUP BASE
Kiminobu Nishimura, Subaru Hujiwara · IEICE Technical Report; IEICE Tech. Rep. · 2008
Electric guitars are world wide used instruments in particular among young ages. Their timbre or impression of tone is different respectively without consideration of characteristics of amplifier or speakers. Then, artists change the guitars sometime to adjust the timbre for each music impression. The basic structure of electric guitar is very similar with stereophonic equipment. That is, the tone signal is detected from string vibration by using electro-magnetic pickup, sent from pickup to guitar amplifier through shield cable, amplified and radiated from a speaker. On the other hand, mechanical vibration caused on strings propagates to the body through nut-neck and/or bridge, reach and excite pickup indirectly, and finally cause the particular tone. Furthermore, the vibration on the body seems fed back to the strings. This mutual feedback system on vibration built up the particular timbre of individual instruments. In this study, how the vibration characteristics on the base of pickup influences to the electrical signal output or its timbre of an electric guitar is studied from experimental viewpoint. Especially, how the mechanical characteristics like the stiffness, the damping factor and density of materials are related to the change of timbre has been researched for popular and inexpensive one. In the experiment, we employed nine kinds of materials of wood, metal and plastic. The difference of materials is appeared in difference on amount of higher harmonics and damping factor at just after of picking and sustain part of string vibration. In consequence, by changing the materials of pickup base, the timbre of output tone from electric guitar changes based on the characteristics of material, and tendency of timbre are roughly related to mechanical characteristics.