When you select any rhythm or style for a song, you assume that the accompaniment is independent of the melody. However, this independence is a fiction that does not exist in music. It comes at the cost of restricting the accompaniment to the lowest common denominator with any imaginable melody. And that denominator consists precisely of the chords or chord tones of the harmony.

Particularly for genres like rock and pop, this tone repertoire is far too limited.

Real accompaniments move within a key along with the melody. Therefore, for every chord, at least melodically, all 7 notes of the respective key can be played. This applies equally to both the melody and the accompaniment.

Since the auto-accompaniment is played with chords, we can also look at it from the perspective of the chords and say that for every chord, at least melodically, all 7 notes of its chord scale can be played. This is merely a different point of view, without changing anything about the underlying facts.

Tones of the Key     =      Available Tones     =      Tone Repertoire     =      Chord Scale    =     Chord Tones    +    Tensions

Both perspectives clearly show that accompaniments play more than just chord tones, which can also be observed in almost all high-quality rock and pop MIDI files. And naturally, the additional tensions are mostly notes of the key.

The auto-accompaniment functions like a backing band made up of several musicians. Rather than limiting themselves solely to chord tones, musicians often utilize available tension tones to add musical depth. In fact, rock and pop bands rarely restrict themselves to only chord tones. Therefore, relying only on basic chords does not cover all the tones in an accompaniment; further insight can be found in our section:  The Way Music Works.

Chord scales provide your backing band with all the notes. They open up a fascinating extension for the auto-accompaniment:

Chord scales relate to the chords and can be calculated and played without any knowledge of the key!

This is exactly what nimbu does. nimbu is the arranger that not only automatically calculates chords from MIDI files, but also simultaneously assigns the corresponding chord scales to these chords. Transposable accompaniments are calculated from MIDI files. For every single note, it is known whether it represents a chord tone or a tension tone. Therefore, the tensions of an accompaniment can easily be reduced to their assigned chord tones in real time, allowing you to play all chords freely with this accompaniment.

When these accompaniments are played using the full note repertoire, with non-diatonic tensions also permitted, song-specific accompaniments of the highest quality are created that are barely distinguishable from the original MIDI file. An audio sample is available in Audio C. Furthermore, the musical relationships are explained in an easy-to-understand manner in Video E,  titled "More Tones for Auto-Accompaniment."

Even if nimbu cannot sufficiently determine a chord scale because there are not enough notes present for the corresponding chord in the MIDI file, this has no impact. During song-specific playback, the missing scale degrees do not even occur. And when playing freely with chords, the existing tension tones (and their scale degrees) are correctly assigned to the chord tones.

Chord scale and key remain underdetermined with no consequences. This is the fundamental approach that nimbu exploits.

Only if you want to improvise correctly with additional tension tones do you need to pay attention to the appropriate assignment of the scales. But even here, nimbu provides you with valuable information. When you cycle through the keys in the nimbu Chord Display according to the circle of fifths, nimbu displays the chords and their chord scales for each key and degree - such as the tonic, subdominant, and dominant - allowing you to play your styles directly from here. nimbu also shows you the so-called avoid notes of the chord scales, which you can only play melodically over the chord and must avoid using within the chords themselves.

Chord scales provide all your accompaniments with the full vocabulary of notes for additional passing tones, more complex chords, riffs, basslines, arpeggios, melodic lines, etc. They are your leverage to play the accompaniment entirely with chords or with just one hand. Do not be intimidated by names like Lydian, Mixolydian, etc. Just like major (Ionian) and minor (Aeolian), they are simply 7-note scales with characteristic intervals. However, these scales enrich and shape your accompaniments with their additional notes.

nimbu translates the chords you play into chord scales with a minimum of 7 notes, allowing you to play anything you want.

Your accompaniments come as close to the original as humanly possible.  This is because their structure corresponds perfectly to our Western music.

You play just like a real band, using all the musically available notes.  This is because your repertoire of notes is derived directly from chord scales. You can even see the scales while playing. The tensions within these scales give your accompaniment the authentic sound of a live band.

Your accompaniments are built very simply and can be easily edited by you. This is because riffs, passing tones, more complex chords, basslines, arpeggios, melodic lines, and more are always made up of the exact same 7 scale degrees.

Yet, you still play as if you were using auto-accompaniment. Any chord you want.  This is because you can switch to chord tones spontaneously. Or you can even play with standard scales that you tailor precisely to your music.

You don’t need to worry about the following details at all. We are simply describing the musical contexts in a bit more depth here. After all, nimbu is musically open and transparent.

Today, playing with auto-accompaniment moves between two extremes. Either the accompaniments are reduced to chord tones so they can be played with different chords, or the accompaniments are simply played back with all notes included, for example as a MIDI file playback.

There are intermediate forms between these two extremes. For instance, in intros and endings more than just chord tones are often played, but then only one or two tones of your played chords are analyzed. With so-called Session Styles the auto-accompaniment even plays the chords within the main sections by itself.

In other words, the larger the note repertoire of the accompaniment, the more limited you are in playing your own chords.

Good musicians therefore sing the melody and use their right hand to play the characteristic sections of the accompaniment themselves. Others use a three-voice chord recognition and use their left hand to play one- or two-voice lines themselves. For a band consisting of several musicians, that is simply not enough.

But there is a completely different way. And that is what we are coming to now.

As an example, let us assume that your piece of music is written in C major. If you play the major chords  C - F - G - C  in C major one after the other, this is called an  I -  IV  -  V  -  I  cadence. There are other cadences as well. Most musical pieces are structured in the form of so-called full cadences.

Let's assume you are playing the F major chord of the IV degree in C major. At this point, your accompaniment can also play all 7 notes of C major. Just like the melody. This applies to every degree or chord of the cadence.

This means that in addition to the notes F, A, and C (of your F major chord), the notes G, B, D, and E can also be played in the accompaniment. That is more than twice as many notes in total.

And this is exactly where chord scales come into play. Chord scales do nothing other than expand the chord tones to the 7 tones of the key. Therefore, in our example, the Lydian chord scale with the root note F must be assigned to the F major chord, featuring its notes:

F         G         A         B         C         D         E

As you can easily see, these are the 7 notes of the key of C major, which provides the tone repertoire :

Tones of the Key     =      Available Tones     =      Tone Repertoire     =      Chord Scale    =     Chord Tones    +    Tensions

This means we can also play all notes in the accompaniment using the corresponding chord scales. We just need to notate the accompaniment in chord scale degrees instead of notes and assign the correct chord scales to the played chords. When playing the chords, these scale degrees of the accompaniment are then matched with the degrees of the chord scale assigned to that chord and thus converted into notes. We will describe exactly how this works in a bit more detail in the very next section.

This way, given known chords and chord scales, an accompaniment in chord scale degrees can be calculated from the notes of any MIDI file, which can then also be played with other chords and other chord scales.

However, a very essential point now comes into play for the auto-accompaniment. As a rule, accompaniments do not play all notes of the key for every chord. The consequence of this is that the chord scales cannot be sufficiently determined from a MIDI file because notes are missing. As a result, several different chord scales could then be considered for the respective chords in the accompaniment.

As mentioned at the very beginning, however, this has absolutely no impact, since these missing notes or scale degrees do not even occur in the accompaniment during song-specific playing and are therefore not played at all. And if every harmony is played freely using only chords or chord tones, the other tension tones are correctly assigned to the chord tones.

For this reason, this concept works brilliantly even without knowledge of the key. Key and chord scale remain mathematically underdetermined without having any musical impact whatsoever.

And that is how you play with auto-accompaniment on a level that opens up a completely new approach to music.

We are coming to that now.

Let's assume that at a specific point in time, an accompaniment track in a MIDI file plays the 9 notes shown on the left in the figure below. The Arabic numerals of the chord degrees and scale degrees indicate the position of individual notes within a chord or a scale (not to be confused with the Roman numerals above used for the degrees of complete chords).

Let us further assume that nimbu has calculated the harmony Cmaj7 from the MIDI file for this specific point in time.

Now, let us also assume that nimbu has assigned the Ionian (and not the Lydian) scale with the root note C to the Cmaj7 chord calculated from the MIDI file. With the help of this scale, the notes of the MIDI track are now converted into scale degrees, as shown in the figure above. Chord degree 1 forms the root note of the chord and merely occupies scale degree 1.

The velocity and timing of the MIDI notes and nimbu events, as well as their note and event lengths, are completely identical; this means the rhythm of the MIDI notes and the nimbu events is exactly the same. nimbu also adopts all time signature changes from the MIDI file. The harmony is simply extracted from the notes of the MIDI track, leaving only the accompaniment in the form of nimbu events with their respective scale degrees.

If you now play this accompaniment with Cmaj7 as shown on the right, nimbu assigns the Ionian scale to this chord. The scale degrees of the nimbu events are converted back into notes via this scale. The notes correspond exactly to the MIDI file.

However, if you play D minor instead of Cmaj7, nimbu calls up the natural minor scale instead of the Ionian scale and uses this scale - now with D as root note - to assign the notes to the individual scale degrees of the nimbu events. Your accompaniment gets a completely new sound. If your musical context requires a scale other than the standard natural minor scale, you must select one of the scales predetermined by nimbu for the D minor chord or, provided the sheet music or note data is available, let nimbu calculate the scale.

The second-to-last note is simply the root note of the scale again, just an octave higher and therefore located in octave range 2. The final note, however, does not belong to the Ionian scale at all. This note is outside the scale (non-diatonic tension). It is created by raising scale degree 3 by a half step, which nimbu also processes and highlights with red events.

Since nimbu inherently plays chord scales, it assigns standard scales to the played chords during performance. These are scales that are frequently used in music for the respective chord types. If these scales do not fit, you specify the correct scales for the corresponding chords (root note + chord type).

This is exactly what nimbu does automatically during MIDI import, while also allowing non-scale events in order to come as close as possible to the original or the song itself. In the Play tab, the Titles setting is active.

You always play using one of these three basic settings:   Auto Accompaniment,  Improvisation or  Title.

When switching to scales, nimbu converts the non-scale notes (non-diatonic tensions) into scale notes (harmonic tensions). The accompaniment is reduced to scale notes. This is the setting for improvisation, which, by its very musical nature, takes place in scales. The chord scales provide you with the note repertoire for your improvisations.

By switching to chords, you can play any harmony completely freely because your accompaniment is reduced to chord tones, as shown in the figure above. This switching can be done at any time or in real-time during your performance, for example via the touch panel. This is the setting for the auto-accompaniment, which can also be activated during a song-specific accompaniment. nimbu then reduces the scale degrees of the accompaniment to the scale degrees of the chords. Scale degree 1 remains scale degree 1, as chord degree 1 only possesses this scale degree. Scale degree 1 forms the common root note of both chord and scale. Scale degrees 2 and 3 become chord degree 2 and scale degree 3 respectively, while scale degrees 4 and 5 become chord degree 3 and scale degree 5, and so on (see illustration). The green scale degrees of the tension tones turn into the blue scale degrees of the chord tones, which doesn't have to sound bad at all in short passages - especially if these passages are more rhythmic than melodic, or if the proportion of tension tones is low. If there are no tension tones present, you can barely hear any difference. You should use chord-based playing sparingly, for instance for spontaneous transitions, to always make the most of the full note repertoire.

nimbu utilizes this concept and uses a sophisticated algorithm to calculate the harmonic progression with scale assignment as well as the accompaniment in scale degrees from MIDI files - without losing a single note in the process. This concept is applicable to all popular hits of Western music.

In the song-specific accompaniment, all you need to do now is set the markers for Intro, Main, etc. You can also develop further variations by copying and editing existing markers. Additionally, the entire accompaniment can be converted to chord tones. However, you don’t have to do the latter at all. You can also keep the characteristic tension tones within the style and switch to chord tones spontaneously or in real-time while playing. Ultimately, all setting options (e.g., shifting the so-called High Keys, transpositions, etc.) are available to you to make the style universally applicable. In nimbu, you can even play your accompaniment with YAMAHA® transpositions (SFF 1 and SFF 2). When everything sounds good, you export the style in SFF1 or SFF2 format to play it on your YAMAHA® keyboard without nimbu.

The reverse process is also possible. Imported keyboard styles, whose main sections primarily consist of chord tones, can also be played using the Titles or Scales settings, even though they do not inherently know any scales. With these settings, very specific processes are triggered in the other sections of these styles - such as intros, which naturally play their own melodic or harmonic components. These are style-specific YAMAHA® transpositions, which will not be discussed here. nimbu plays all YAMAHA® transpositions. You can also modify these transposition settings of the imported styles.

Ultimately, you can easily edit these styles as well and adapt them to your own ideas, allowing you to even integrate the characteristic tension tones. Even in the nimbu Core Edition, you have complete freedom to develop a song-specific accompaniment from any style.

nimbu - playing like a real band.  Experience it for yourself.  Right now.  Here is our offer.


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