Accordion bellows are the concertinaed section in the center of an accordion. The bellows are expanded and contracted to pass air through various metal reeds inside the instrument that are responsible for the generation of noise. An accordion will not make any sound unless the bellows are contracted or expanded. The main concern of the bellows for an accordionist is the effect they will have on the tone produced by the instrument.
A Chinese instrument, the cheng, was the first recorded instrument to use vibrating reeds as a means of making sound, but the accordion known today originated from Germany. There are two different types of accordion, the diatonic accordion and the piano accordion. The piano accordion is generally the most familiar type, and it features a piano keyboard on one side and several small bass buttons on the other. The diatonic accordion can only produce notes in a set number of keys, and has circular melody buttons in rows of ten and very few bass buttons. A diatonic accordion produces a different note depending on which way the bellows are pulled, and a piano accordion does not.
Regardless of the type of accordion, the bellows are always required to produce sound. Accordion bellows are found between the bass buttons and the melody buttons of the accordion. Accordions often have special “air” buttons, which allow air to be passed through the bellows without a note being produced on the instrument. Some pieces of music for the accordion have specific notation regarding whether the bellows are to be expanded or contracted during a certain measure. The two main aims for controlling the accordion bellows are stability and tone.
Most accordion players will sit the melody side of the accordion on the knee below their stronger hand. The accordion bellows are usually operated by the weaker hand, with the melody section and that half of the instrument remaining stationary on the player’s knee. This helps to enable stability of the instrument, which in turn allows more control over the specific tone produced and more dexterity of the fingers.
Supporting the bellows is only important because the accordion bellows have a big impact on the sound produced by the instrument. Pushing or pulling the bellows hard will produce a louder, harsher tone than doing so softly. Experienced players develop a sense of how to work the bellows depending on the intended mood of the piece of music. The direction the bellows are being moved in changes every bar, every two bars or every four bars.