Stradella bass system
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The Stradella Bass System (sometimes called standard bass) is a buttonboard layout equipped on the bass side of many accordions, which uses columns of buttons arranged in a circle of fifths; this places the principal major chords of a key (I, IV and V) in three adjacent columns. In a typical layout, as pictured, each column contains, in order:
- The major third above the root ("counter-bass")
- The root note
- The major chord
- The minor chord
- The dominant seventh chord
- The diminished seventh chord
The following chart shows a common 120-button Stradella layout.
In modern accordions, each chord button sounds three individual pitches. Early accordions sounded four pitches for the seventh and diminished chords. Modern Stradella systems omit the 5th from these two chords, allowing for more versatility. For example, an augmented seventh chord can be created by using the dominant seventh chord button and adding an augmented 5th from the right-hand manual or from one of the bass or counterbass buttons.
In most Russian layouts the diminished seventh chord row is moved by one button, so that the C diminished seventh chord is where the F diminished seventh chord would be in a standard Stradella layout; this is done in order to achieve a better reachability with the forefinger.
As the buttons are on the front face and cannot be seen by the player, an aid to navigation is provided by a small depression, hole or bump on the central C button in the root row, often supplemented by similar or different tactile marks on other selected root-bass buttons, such as the A♭ and E four buttons away in either direction.
When naming chord buttons, major chords are often suffixed with "M", for example "CM", to distinguish them from bass notes.
In staff notation, notes below the center of the bass-clef staff are bass notes, and notes above the center of the staff usually indicate chord buttons, labeled as necessary with "M", "m", "7", or "d" or "dim". (Repeated chords are usually only labeled on the first instance.)
Within this convention, the written octave for bass notes is arbitrary, as the Stradella system does not have buttons for higher and lower octaves.
As sounded, with one possible octave voicing:
Bass notes to be played on the major third (counterbass) row are indicated by repurposed "tenuto" lines below the notes (as in the E bass note in the example above), or underlined note names or numbers.
Single-note bass lines are often labeled "B.S." (bass solo or bassi soli), especially when they extend above the middle of the staff.
As with the piano, fingers are numbered 2 to 5, starting with the index finger, mirroring right-hand fingering. As a rule, the thumb, numbered 1, is not used.
Patterns can be played identically in any desired key, changing only the starting position; this is because unlike a piano keyboard, the Stradella layout does not distinguish between "white notes" and "black notes". Layouts with 16 or more columns are sufficient to play in any of the 12 keys of the circle of fifths.
Bass and chords
4–3 is a recommended fingering for a bass note and its corresponding major chord (e.g. C–CM–C–CM). For alternate bass with the root and fifth, 4–3–2–3 can be used for major chords (e.g. C–CM–G–CM), 4–2–3–2 for minor and other types of chords (e.g. C–C7–G–C7).
Scales, runs, and other bass lines are played on the bass note buttons, the row or rows closest to the bellows (root row, optional thirds row, optional minor thirds row).
The major scale can be fingered without stretching the hand, playing in any key as r4 r2 t4 r5 / r3 t5 t3 r4 (r = root row, t = thirds row) or, with minimal movement of the index finger, r3 r2 t3 r4 / r2 t4 t2 r3.
Melodic minor (different ascending and descending):
Larger and more expensive accordions may have as many as seven register switches on the bass side, controlling which reed ranks play and thus the octaves and voicing of the bass notes and chords, similar in concept to the treble register switches on the keyboard side. Smaller or simpler accordions may have no bass switches, or a single switch that toggles between two settings.
Bass register switches and reed sets of a typical professional-grade accordion Register switch Reed sets Soprano
Name Symbol (chords and bass notes) (bass notes only) soprano alto tenor soft tenor master or
soft bass or
With the soprano or alto register selected, bass buttons exactly duplicate individual notes from the chords, without the usual added lower (tenor and bass) octaves.
An accordion with two register switches on the bass side might provide tenor and master registers, while accordions with additional switches might have larger subsets.
Name Columns Rows of bass notes Rows of chords 8-bass 4 – Root notes: F to D Root note Major 12-bass 6 – Root notes: B♭ to A Root note Major 24-bass 8 – Root notes: E♭ to E Root note Major, minor 32-bass 8 – Root notes: E♭ to E Root note Major, minor, 7th 40-bass 8 – Root notes: E♭ to E Major 3rd note, root note Major, minor, 7th 48-bass 8 – Root notes: E♭ to E Major 3rd note, root note Major, minor, 7th, diminished 12 – Root notes: D♭ to F♯ Major 3rd note, root note Major, minor 60-bass 12 – Root notes: D♭ to F♯ Major 3rd note, root note Major, minor, 7th 72-bass 12 – Root notes: D♭ to F♯ Major 3rd note, root note Major, minor, 7th, diminished 80-bass 16 – Root notes: C♭ to G♯ Major 3rd note, root note Major, minor, 7th 96-bass 16 – Root notes: C♭ to G♯ Major 3rd note, root note Major, minor, 7th, diminished 120-bass 20 – Root notes: B[notes 1] to A♯ Major 3rd note, root note Major, minor, 7th, diminished Minor 3rd, major 3rd, root note Major, minor, 7th 140-bass 20 – Root notes: B[notes 1] to A♯ Major 3rd note, root note Major, minor, 7th, diminished, augmented[notes 2] Minor 3rd note,[notes 2] major 3rd note, root note Major, minor, 7th, diminished 160-bass 20 – Root notes: B[notes 1] to A♯ Three major 3rd rows, root note Major, minor, 7th, diminished
- B is often referred to as "low A"; enharmonic equivalents play the same reeds.
- 140-bass accordions may come with either an extra minor 3rd note row, located above the regular major 3rd row and the root note, or an augmented 7th chord row.
- Balestrieri, Donald (1979). "Registers of the Standard Stradella Keyboard". Accordions Worldwide. Retrieved 24 August 2014.
- "Accordion Anatomy". Western New York Accordion Club. Retrieved 19 March 2017.
- Zucco, Frank (1985). Mel Bay's Deluxe Accordion Method. Pacific, Mo.: Mel Bay Publications. ISBN 978-0871667823.
- Dahl, Gary (2004). Mel Bay's Master Accordion Scale Book With Jazz Scale Studies. Pacific, Mo.: Mel Bay Publications. ISBN 978-078666708-6.
- "Accordion Anatomy". Western New York Accordion Club. See diagram "Bass Reed Switches". Retrieved 30 May 2015.