Sizes of Piano Accordions

8 Bass	60 Bass
12 Bass	72 Bass
16 Bass	75 Bass
24 Bass	80 Bass
32 Bass	96 Bass
40 Bass	111 Bass
48 Bass	120 Bass
50 Bass	140 Bass

Piano keyboard accordions are sized by the number of bassesthey have, anywhere from 12 basses for astudent instrument up to the standard 120 bass full-sized accordion. There are toys and vintage models that are smaller, and oddball instruments with extra basses, or fewer basses, but most instruments will fall in that range.

When choosing an accordion, check the width of the treble keyboard and the width of each white key. Standard size keys are just a little narrower than piano keys: about 3/4". If you are used to playing the piano, or have larger hands, you may have trouble playing an accordion with smaller than standard keys.

A standard instrument with 6 bass / chord rows for each key has the following bass buttons, from top to bottom (bottom being closest to the player's wrist):
Counterbass / Fundamental Bass / Major Chord / Minor Chord / 7th Chord / Diminished Chord.

• 12 Bass 2x6
  2 bass/chord rows by 6 key rows.
  The bass/chord rows are the fundamental bass and the major chord, and the key rows are Bb - F - C - G - D - A.
  
  This is often the first accordion for young students, as it is small, lightweight and easy to play, and used ones can be found for relatively low prices. The treble keyboard is 2 octaves, usually from middle C to C'' (25 keys), although a few begin on B (26 keys). Some 12 bass instruments, especially older ones, have surprisingly nice tone, good volume, and fast response. They have 2 treble voices, sometimes tuned musette and sometimes an octave apart. Although they are harmonically limited without the minor chords, one can fake a minor chord sound - there are several possible workarounds. Folk musicians often prize older 12b accordions for their sound, portability, agility, and economy, and use them for everything from Morris dance music to polkas.
  

• 16 Bass 2x8
  2 bass/chord rows by 8 key rows. Same keyboard as the 12 bass, but with the added keys of Eb and E in the bass. I've only seen the cheap Chinese ones, and they aren't being imported at the moment - no great loss.
  

• 24 Bass 3x8 or 4x6:
  Two possible bass arrangements: 3 bass/chord rows by 8 key rows, or 4 bass/chord rows by 6 key rows.
  In the first setup, which is much more likely, the bass/chord rows are arranged bass, major chord, minor chord; although it would be possible to have counterbass, fundamental bass, and major chord. Same 8 key rows as a 48 bass 6x8, and same treble keyboard as a 12 bass. This size is hard to find, but prized by folk musicians. I've only seen older instruments, like the old Hohners and Frontalinis, or the rhinestone-spattered Serani I bought from Bob McQuillen at the 1995 Northeast Squeeze-In.

• 32 Bass 4x8:
  There are 2 possible bass arrangements, both in a pattern of 4 bass/chord rows by 8 key rows. The rows are either counterbass, bass, major, minor; or else bass, major, minor, 7th. The counterbass row is preferable to the 7th row, but unfortunately most modern models seem to be made with the 7th. It has the same 8 key rows as on a 24 bass 3x8 and a 48 bass 6x8, still with that short 26 key treble side. There aren't many being manufactured today.
  

• 40 Bass 5x8:
  5 bass/chord rows by 8 key rows, the same 8 rows as the 32 and the 48 6x8. The bass/chord rows are counterbass, bass, major, minor, and 7th. 26 trebles, 2 octaves. The only ones I've seen are made in Germany and marketed by Hohner and Castiglione, and have 3 switches. I'd like to see a 4x10 instead - more useful.
  

• 48 Bass
  My favorite size of accordion, in the 4x12 arrangement. Can have either 2 voices, with or without musette, or 3 voices, with musette, and from 26 to 34 treble keys, which can be standard size or ladies size. Weight can range from about 12 lbs up to about 17 lbs, with most of them being on the lighter end. Our print catalog used to show an old engraving of a Stradella brand 48 bass with 3 x16 basses, but I've never seen a live one with that configuration. Commonly seen in 2 different bass setups:
  
  • 6x8: 6 bass/chord rows by 8 key rows:
    The key rows are : Eb - Bb - F - C - G - D - A - E, same as the other smaller 8 row instruments. Sometimes called the "short 48" both because of the shorter bass key rows, and also because the treble keyboard is short, like the smaller instruments, with only a little more than 2 octaves (usually 26 to 30 keys). This makes playing fiddle music somewhat problematical, without the low G and A. The bass is a nice setup if you don't plan to play much in the sharp or flat keys, and you like to use 7th and diminished chords. However, it won't work for some types of folk music such as Irish and French Canadian, where the key of Bm is a very important key. There are always workarounds, but sometimes it's better just to have the missing rows.

  • 4x12: 4 bass/chord rows by 12 key rows:
    This is an almost ideal setup for most folk music. Small and lightweight, it usually has 34 treble keys, from G below middle C up to a high E, or 2 3/4 octaves - the range needed for fiddle music (same low range as a violin on the keyboard side). More importantly, it also has all 12 key rows in the bass, centered in the fiddle keys, and without the redundant rows built into larger accordions. I have seen 2 different key row arrangements in the 4x12 bass. Setup #1 is the normal setup. I wish I could find more accordions with #2. The center of the key range is in bold print, denoting the keys that allow the most versatility in terms of chord changes:
    #1 (usually seen): Db - Ab - Eb - Bb - F - C - G - D - A - E - B - F#
    #2 (very rare): Ab - Eb - Bb - F - C - G - D - A - E - B - F# - C#

    The 7th and diminished rows are absent on the 4x12. Most of the older 48's were made in this size, like the old Hohner Tango, Imperial III, Verdi, and Carmen student 48 models, and the sleeker Scandalli "Silvietto" 48. A few of the old 48's had a short keyboard only going down to a B below middle C, with only 26 keys, but most had the more useful 34 trebles. Castiglione makes a German 4x12 but with only 26 trebles.
    

• 50b 5x10:
  5 bass/chord rows by 10 key rows. This size is made by Gabbanelli and Titano. It's a very well made junior sized accordion. The setup is a little more versatile than the 48b 6x8 bass arrangement. The trebles are 30 keys. The bass is missing the diminished chord row, but has the added key rows of B and Ab, like this:
  Ab - Eb - Bb - F - C - G - D - A - E - B

• 60b 5x12: 5 bass/chord rows by 12 key rows. Now we have all 12 key rows, as well as the 7th chord row, but still no diminished chord row. This is a nice lightweight accordion, suitable for most folk music, and many other kinds of music where the diminished chord is really not necessary. Treble keyboard from 26 to 34 keys, with 2 to 3 voices. Castiglione makes this size.
  

• 72b 6x12
  6 bass/chord rows by 12 key rows. The 72 bass setup is a nice one for many kinds of music. It is basically like a 4x12 except you also get the 7th and dim. chords. Unless you need to play in very sharp or very flat keys, this accordion setup is a nice compromise between the range of a 120b and the light weight of a 48b. Treble keyboard anywhere from 26 to 37 keys, usually with 2 or 3 reeds (voices). Castiglione, Titano, Guerrini, Gabbanelli, Victoria, Hohner, and others.
  

• 80b 5x16
  5 bass/chord rows by 16 key rows. Made by Petosa, Delicia, Scandalli, Hohner, Excelsior, others. A more intelligent and useful arrangement than the 72 bass, but less common nowadays than in the Golden Age. Missing only the diminished chord, this is a very nice setup for folk musicians who occasionally need to play in the very flat and sharp keys (4 or 5 black keys), yet want something smaller than a 120. There are 4 additional key rows so there is an overlap at the top and bottom of the bass keyboard, making it easy to play full chord progressions in almost any key, without a lot of jumping around. Usually seen with 3 treble voices, but sometimes 4. Treble keyboard usually 34 or 37 keys. Here is the key row arrangement in the bass:
  Cb(B) - Gb(F#) - Db(C#) - Ab(G#) - Eb - Bb - F - C - G - D - A - E - B - F# - C# - G#

• 96b 6x16
  6 bass/chord rows by 16 key rows. Same as the 80b but now the diminished row is added on. Treble keyboard usually 37 to 41 keys. Can be either heavier or lighter than full sized accordions, depending on features and number of reeds.
  

• 120 Bass Accordions
  This is the normal full complement of basses: 6 bass/chord rows by 20 key rows. These come in a wide range of weights (about 15 lbs up to 28 lbs or more) and sizes. Keyboard widths can range from a tiny 14 1/2" up to 19 1/4", usually with a 41 key treble keyboard (F to A''', more than 3 octaves), and with key widths ranging from a very narrow 9/16"on the midget size, to the spinet sized 5/8", to the regular 3/4" wide white keys. Extended keyboards up to 46 treble keys, and with up to 160 basses, are out there, but are pretty rare.

  Full size as well as spinet or junior sized 120 bass accordions are usually found with from 2 to 4 treble voices (very rarely, 5), a wide variety and number of registers, and from 4 to 7 bass reeds, and canalso feature different bass systems: regular Stradella, Stradella free bass, chromatic freebass (Bassetti), and convertor bass. Professional full size instruments may also have tone chambers, also called cassotto, for one or more reed banks.

  There are other, less common, sizes and styles of piano accordion, but they're curiosities and you're not likely to run across them unless you're a collector. These are the ones I've seen, in my many years of playing, collecting, and selling them.