The bridge is found somewhere between the middle and end of the body. Depending on the guitar, the strings may originate from the bridge or they might simply be supported by it.
Most guitars allow the bridge to be raised or lowered, an adjustment necessary in setting up the guitar that may easily and safely be performed by any guitarist. This is typically done by adjusting screws, which are either thumbscrews which can be rotated with the fingers, or traditional screws requiring a screwdriver.
Did you know? The main purpose of the bridge on an acoustic guitar is to transfer the vibration from the strings to the soundboard, which vibrates the air inside of the guitar, thereby amplifying the sound produced by the strings.
On both electric and acoustic guitars, the bridge holds the strings in place. From there, the variations are astounding. There may be some mechanism for raising or lowering the bridge to adjust the distance between the strings and the fretboard (action), and/or fine-tuning the intonation of the instrument. Some are springloaded and feature a "whammy bar" (primarily on electric guitars) a removable arm which allows the player to modulate the pitch moving the bridge up and down.
The whammy bar is sometimes incorrectly referred to as a "tremolo bar"; unlike the change in pitch that the whammy bar produces, a tremolo is a quick oscillation of the volume. Some bridges allow for alternate tunings at the touch of a button.
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