At the basis of the design process of the guitar bridges lay an elaborate scientific research regarding the sound preference and judgement of different bass models. The goal of the study was to find out the sound preference of bass players and ultimately the effect of the newly designed bridge.
Sixteen bass players (14 students and 2 teachers at the Rotterdam School of Music) were asked to arrange the sounds from most preferred to least preferred sound. Weighted results are shown in in the figure at the right. When a sound was judged most preferred it would get ten points and when judged second most preferred 9 points up until 1 point for the least preferred sound. These values for every sound were added up. The study showed that the sound of the bass guitar of AI was the most preferred sound.
The figure below presents a comparison of the two worst judged sounds with the two best judged sounds. The horizontal axis shows the frequencies using the Bark scale and the vertical axis the excitation in phons. The Bark and phon scale are used in order to compensate for the effect of frequency on the perceived loudness of tones, as for the same sound pressure very high and low frequencies are perceived quieter by the human ear. We can see that the two sounds judged least preferred have significantly more energy in the higher frequencies in between 2000 and 12000Hz. We concluded that the most distinguishing aspects for the bass sound are a clear fundamental (1) and a steady loss of energy in the higher frequencies (2).
The figure at the left shows the Bark frequency spectrum of the O5O with the regular bridge as recorded during the tone study in the analysis phase and the sound of the prototype.
The graph shows that the new bridge makes the fundamental stand out even more. This is shown by minor frequency dip at 5 Bark (510Hz). This thus is a significant improvement as compared with the traditional bass bridge.