Accordion reed ranks & 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 anywhere between 2-4 reed ranks on the treble side and 3-5 reed ranks on the bass side that can usually be selected individually and/or be combined differently to provide a range of different timbres, by use of switches arranged by register from high to low. More of the top-line expensive accordions may contain 5-6 reed blocks on the treble side for different tunings, typically found in accordions which stress musette sounds.

How many reeds an accordion has is defined by a method that looks like a fraction. 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 usually classified by either organ 'foot-length' stops or instrument names. Visually, they each have a fixed dot in a three-level chart as displayed in the photo on the right and tables below. These charts are also used to display when more than one reed-rank is in use.

Register stop classifications

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.

To hear how these sound on their own, see the first three rows of the table below.

Register switches

Register switches control how contrasting timbres are produced. They control which reed ranks are enabled (opened up) or disabled (closed off), in a similar manner to the register switches controlling the organ stops of a pipe organ: a single reed rank, or several simultaneous reed ranks. Unlike a pipe organ, only one switch can be active at any given time. Here are a few examples of right-hand manual switches on a typical large accordion [Table made with reference from [http://www.newmusicbox.org/news.nmbx?id=00463 this article at NewMusicbox] ] (Smaller boxes with fewer reed banks may have fewer switches or even none):

In addition to the master switch located with the other switches shown above, professional grade accordions often have a least one extra master switch: either a "chin" master or "wrist" master switch. These are located in positions that allow for faster changes to the full sound during playing.

Cassotto

More expensive accordions have a "Cassotto". It is an Italian word meaning "box"; it is also referred to as a "tone chamber" [ [http://www.freepatentsonline.com/EP0545868.html European Patent EP0545868 Kind Code:A1] , a patent on an "Accordion with variable keys and one or two reeds in the "Cassotto"."] . The reeds that are placed in this chamber have a far more mellow and rich tone. The box often has a means of opening or closing to vary the sound.

References