page_title: Accordion
section_title: Pallet mechanism
hierarchical_section_title: Accordion / Construction / Universal components / Pallet mechanism
context_page_description: Accordions are a family of box-shaped musical instruments of the bellows-driven free-reed aerophone type, colloquially referred to as a squeezebox. A person who plays the accordion is called an accordionist. The concertina and bandoneón are related. The harmonium and American reed organ are in the same family, but are typically larger than an accordion and sit on a surface or the floor.
  The accordion is played by compressing or expanding the bellows while pressing buttons or keys, causing pallets to open, which allow air to flow across strips of brass or steel, called reeds. These vibrate to produce sound inside the body. Valves on opposing reeds of each note are used to make the instrument's reeds sound louder without air leaking from each reed block. The performer normally plays the melody on buttons or keys on the right-hand manual, and the accompaniment, consisting of bass and pre-set chord buttons, on the left-hand manual.
  The accordion is widely spread across the world because of the waves of immigration from Europe to the Americas and other regions.
context_section_description: The accordion is an aerophone. The manual mechanism of the instrument either enables the air flow, or disables it:
caption: A side view of the pallet mechanism in a piano accordion. As the key is pressed down the pallet is lifted, allowing for air to enter the tone chamber in either direction and excite the reeds; air flow direction depends on the direction of bellows movement. A similar mechanical pallet movement is used in button accordions, as well as for bass mechanisms such as the Stradella bass machine that translates a single button press into multiple pallet openings for the notes of a chord.