Accordion reed ranks and switches

A reed rank inside accordions refers to a single full set of the reeds that are the means to achieve the instrument's sound range. These reed ranks are located in the reed chamber. Most accordions to this date typically have between 2 and 4 reed ranks on the treble side and between 3 and 5 reed ranks on the bass side. These can usually be selected individually or combined in various ways to provide a range of different timbres, by use of register switches arranged by register from high to low. More of the top-line expensive accordions may contain 5 or 6 reed blocks on the treble side for different tunings, typically found in accordions which stress musette sounds.

How many reeds an accordion has is specified by the number of treble ranks and bass ranks. For example, a 4/5 accordion has 4 reeds on the treble side and 5 on the bass side. A 3/4 accordion has 3 reeds on the treble sides and 4 on the bass side.

Reed ranks are classified by either organ 'foot-length' stops or instrument names. Visually, they each have a fixed dot in a three-level icon as displayed in the photo on the right and tables below. These icons display when more than one reed-rank is in use.

The pitch of a single bank of reeds is traditionally defined in a similar manner to the organ stops of a pipe organ. A bank that sounds at unison pitch when keys are depressed is called 8′ (pronounced "eight-foot") pitch: alluding to the length of the lowest-sounding organ pipe in that rank, which is approximately eight feet. For the same reason, a stop that sounds an octave higher is at 4′ pitch, and one that sounds an octave lower than unison pitch is at 16′ pitch.

Most reed registers are normally in relative octave tuning, but rarely, some instruments have a reed bank tuned to a perfect fifth relative to the 8′ stop (or some octave of that). This is a similar arrangement to stops for a pipe organ.

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