The Yamaha keyboard style files contain a number of sections:
• A MIDI section, where the MIDI information is divided into parts. Read more here.
• A CASM section, where the Ctab are set. This document describes this section. CASM Format 1 Reference and CASM Format 2 Reference for CASM software programmers.
• An OTS section, where the One Touch Settings are defined. Read more here.
• A MDB section, where the Music Data Base records are set. Read more here.

Read about style format differences and how to convert between models at Style File Features.

CASM sections can be created and edited with my CASM Editor software.

The CASM section holds the Ctab settings and some other settings of the style. Only some of these settings can be done at the keyboard.

The CASM section defines values for all channels (up to 16) and all style parts (up to 15 depending on keyboard model).
For all these combinations, the CASM defines:

Redirection schema

This scheme defines how the 16 source channels are used in the 8 keyboard style channels: Rhythm Sub, Rhythm Main, Bass, Chord 1, Chord 2, Pad, Phrase 1 and Phrase 2.

This feature is the key in utilizing the "Active Chords" settings.

Chord Root / Chord Type

These settings determine the original key of the source pattern (i.e. the key used when recording the pattern).

The default is CMaj7 (the chord root is "C" and the chord type is "Maj7").

Valid Chord Types:
Maj, Maj6, Maj7, M7#11, Madd9, M7(9), M6(9), aug, m, m6, m7, m7b5, m(9), m7(9), m7(11), mM7, mM7(9), dim, dim7, 7, 7sus, 7b5, 7(9), 7(#11), 7(13), 7(b9), 7(b13), 7(#9), M7aug, 7aug, 1+8, 1+5, sus4 and 1+2+5

Note Transposition Rule

NTR specify the transposition rule to be used by the transposition table. Three settings are available:

ROOT TRANS:
When transposed the pitch relationship between notes is maintained. For example, the notes C3, E3, and G3 in the key of C will become F3, A3, and C4 when transposed to F. Use this setting for parts that contain melodic lines.

ROOT FIXED:
The note is kept as close as possible to the previous note range. For example, the notes C3, E3, and G3 in the key of C will become C3, F3, and A3 when transposed to F. Use this setting for chordal parts.

GUITAR:
(SFF2 format only. More)
This is exclusively for transposing guitar accompaniment. Notes are transposed to approximate the chords played with natural guitar fingering.

Note Transposition Table

NTT specify the note transposition table to be used for source pattern transposition.

The following table types are available for Note Transposition Rule "Root Trans" and "Root Fixed":

BYPASS:
No transposition.

MELODY:
Suitable for melody line transposition. Use for melody parts such as PHRASE 1 and PHRASE 2.

CHORD:
Suitable for chord transposition. Use for the CHORD 1 and CHORD 2 parts when they contain piano or guitar-like chordal parts.

BASS
(Replaced by MELODY in newer models):
Suitable for bass line transposition. This table is basically similar to the MELODY table, but recognizes "on-bass" chords allowed in the FINGERED 2 fingering mode. Use primarily for bass lines.

MELODIC MINOR:
This table lowers the third scale degree by a semitone when changing from a major to a minor chord, or raises the minor third scale degree a semitone when changing from a minor to a major chord. Other notes are not changed. Use for parts which respond to major/minor chords, e.g. Intros and Endings.

MELODIC MINOR 5th Var.:
In addition to the table above, augmented and diminished chords affects the 5th note of the pattern.

HARMONIC MINOR:
This table lowers the third and sixth scale degrees by a semitone when changing from a major to a minor chord, or raises the minor third and flatted sixth scale degrees a semitone when changing from a minor to a major chord. Other notes are not changed. Use for parts which respond to major/minor chords, e.g. Intros and Endings.

HARMONIC MINOR 5th Var.:
In addition to the table above, augmented and diminished chords affects the 5th note of the pattern.

NATURAL MINOR:
This table lowers the third, sixth and seventh intervals in the scale by a semitone when changing from a major to a minor chord; or raises the minor third, flatted sixth and flattened seventh intervals by a semitone when changing from a minor to a major chord. Other notes are not changed. Use for parts which respond to major/minor chords, e.g. Intros and Endings.

NATURAL MINOR 5th Var.:
In addition to the table above, augmented and diminished chords affects the 5th note of the pattern.

DORIAN:
This table lowers the third and seventh intervals in the scale by a semitone when changing from a major to a minor chord; or raises the minor third and flattened seventh intervals by a semitone when changing from a minor to a major chord. Other notes are not changed. Use for parts which respond to major/minor chords, e.g. Intros and Endings.

DORIAN 5th Var.:
In addition to the table above, augmented and diminished chords affects the 5th note of the pattern.

The following table types are available for Note Transposition Rule "Guitar":
(SFF2 format only. More)

ALL-PURPOSE:
This table covers both strummed- and arpeggio-played sound.

STROKE:
Suitable for stroke-played sound of the guitar. Some notes may sound as if it is muted. This is normal condition when the chord is played on guitar by stroke.

ARPEGGIO:
Suitable for arpeggio-played sound of the guitar. Using this table, four notes arpeggio sounds most beautiful.

High Key

HIGH KEY specifies the upper root limit.
Chords with a root higher than the specified limit will be played in the octave immediately below the high-key limit.

This setting is effective only when the NTR parameter (above) is set to ROOT TRANS.

Example:
When HIGH KEY = F.
Root Motion: C C# D F F#
Notes Produced: C3-E3-G3 / C#3-F3-G#3 / D3-F#3-A3 / F3-A3-C4 / F#2-A#2-C#3

Note Low Limit / Note High Limit

NOTE LIMIT LOW and HIGH specify the low and high note limits for all notes in the specified part.

Notes outside this range are transposed to the nearest octave within the range.

Example:
When LOW = C3 and HIGH = D4
Root Motion: C C# D#
Notes Produced: E3-G3-C4 / F3-G#3-C#4 / D#3-G3-A#3

Retrigger Rule

RTR (Retrigger Rule) specify how notes held through chord changes will be handled. These settings are available:

STOP:
The note is stopped, and resumes sounding from the next note data.

PITCH SHIFT:
The pitch of the note will bend without attack to match the type of the new chord.

PITCH SHIFT TO ROOT:
The pitch of the note will bend without attack to match the root of the new chord.

RETRIGGER:
The note is retriggered with attack at a new pitch matching the new chord type.

RETRIGGER TO ROOT:
The note is retriggered with attack at a new pitch matching the new chord root.

Bass On

If set, the channel recognizes on-bass chords allowed in the Fingered On Bass mode, regardless of the NTT setting.

Auto Start

If set, the channel will start playing when a key is pressed (if Sync Start is On). Normally used for Drum and Percussion channels.

Editable

If set, the channel can be edited in the Keyboard Style Creator.

Active Keys

If a note value (e.g. the "A" note) is set to "On", all "A" notes in the channel will play.
If a note value is set to "Off" all notes of this value in the channel will be muted.

Valid note values:
C - C# - D - Eb - E - F - F# - G - Ab - A - Bb - B

Active Chords

If a chord type (e.g. the "aug" chord) is set to "On", all "aug" chords in the channel will play.
If a chord type is set to "Off" all chords of this type in the channel will be muted.

This feature in conjunction with the Redirection schema makes it possible to create multiple pattern channels for one voice, e.g. the Bass channel.
Often one channel is designed for Major chords, another one for minor chords and a third one for 7th chords.
Details described in Style Creation Course - Part 11.

Valid chord types:
Maj, Maj6, Maj7, M7#11, Madd9, M7(9), M6(9), aug, m, m6, m7, m7b5, m(9), m7(9), m7(11), mM7, mM7(9), dim, dim7, 7, 7sus, 7b5, 7(9), 7(#11), 7(13), 7(b9), 7(b13), 7(#9), M7aug, 7aug, 1+8, 1+5, sus4, 1+2+5