When talking about guitar bridges, we have to include the method of manufacture and the material used and the resonant properties.
The job of a guitar bridge is to transfer the guitarist's musical message to the body of the instrument.
But it is also about transferring the resulting sound of the guitar back to the strings in order to define the overall acoustic sound of the instrument before the signal is electrified.
Complex shapes can be easily produced by die casting and is ideally suited for large production runs typically 10,000 units or more at a rate of several hundred per hour, so costs are low.
Sounds good but if you cut one in half you will see a solid outer shell and an aerated inside which is not great for resonance as the open structure dissipates any vibrations rather quickly, in addition the tolerances are not great so you end up with loose fitting parts which require springs and other parts to hold everything together adversely affecting resonance. The materials of Zinc and Aluminium were used because that was available for die casting at the time.
In short die casting is fast, cheap but not really suited to instruments and sound transmission but it was the only way to make TOM’s and Stop Bars in the 1950’s
Back in the 1950’s CNC machines were not available but now you can program virtually any shape, machine it from any material to very tight tolerances and because of the solid nature if the material you do not need to cover it with thick plating which further enhances resonance and gives a cleaner crisper look. CNC machining is a one at a time operation, so production is much slower which explains the higher cost.
In short CNC made bridges are resonant, solid and ideally suited to instruments and sound transmission.
Ensures a very resonant midrange and percussive bass. The material supports a strong fundamental tone with light compression and a rich overtone structure. Bell brass offers excellent string separation and long sustain.
is perfect for a sophisticated electric guitar sound with tight bass, neutral mids, and a long decay with an emphasis on the upper treble (twang).
Has a very fast response and a neutral transmission of tone. It is best suited to heavy or low-resonance instruments.
In a nutshell, brass and steel shape the guitar tone, while aluminium acts largely neutrally in transferring sound information.
