Introduction
Another great and simple way to build tension in your improvisation is through the use of Bitonality and Side-Slipping.
Bitonality
Bitonality (a form of Polytonality) simply means playing a scale other than the diatonic scale of a chord progression. This is very common in Jazz, because of the Chord-Scale System.
| Chord | Potential Scale | Notes |
|---|---|---|
| Dm7 | D Dorian | D E F G A B C |
| D Phrygian | D E♭ F G A B♭ C | |
| A♭ Major | A♭ B♭ C D♭ E♭ F G | |
| G7 | G Mixolydian | G A B C D E F |
| G Altered | G A♭ B♭ C♭ D♭ E♭ F | |
| E Major | E F# G# A B C# D# | |
| CMaj7 | C Ionian | C D E F G A B |
| C Lydian Augmented | C D E F# G# A B | |
| A Major | A B C# D E F# G# |
If we take a II-V-I in C (as above), we can use a number of different scales (from different keys) over each chord. The top scale listed for each chord is in the key of C Major. The middle scale is in a different key but one that can plausibly be used and sound good. The last scale (in red) doesn’t quite fit and so will create a high degree of tension and dissonance if played over those particular chords.
This technique can be used to create tension by playing an ‘incorrect’ scale, before resolving it back to the appropriate diatonic scale or a Guide Tone. For example, playing the A Major Scale over a CMaj7 chord can create some interesting and dissonant sounds, before returning to the C Major Scale and resolving the tension.
When choosing a bitonal scale to use over a chord progression, keep the following in mind:
- The more closely related the bitonal scale is to the diatonic scale (i.e. the closer the two notes are on the Circle of Fifths – we will cover the Circle of Fifths in a future lesson) the more consonant or pleasant the scale will sound.
- For example, playing the G Major Scale over a Chord Progression in the key of C Major is quite smooth and pleasant because there is only one note difference between the G Major and C Major Scale (F# instead of F).
- Playing the G♭ Major Scale on the other hand, will be quite dissonant.
- The bitonal scale will ‘fit’ better if it retains the two Guide Tones of the chord.
- For example, playing G♭ Major Scale over a G7 chord – the G♭ Major scale contains the notes B and F.
- Sometimes, using bitonality can actually make your solo sound more consonant and pleasant by choosing scales that do not have avoid notes.
Side-Slipping
Side-Slipping is a fantastic and really simple Jazz improvisation technique that sounds great. All it involves is playing a phrase in the diatonic scale, repeating the phrase one semitone above or below, before returning back to the diatonic scale. For example, you could play a phrase in C Major and then repeat it in either D♭ Major (one semitone higher) or B Major (one semitone lower) and then return to C Major. So you’re just slipping to the side for a brief instant. This works especially well with side-slipping arpeggios.
This technique works well because:
- You’re only displacing the ‘correct’ scale by one semitone before quickly returning to it (resolving it);
- By repeating a phrase, you create a strong link between the ‘wrong’ notes and the ‘right’ notes. You’re NOT just playing ‘wrong’ notes at random. You are playing them in a very structured way – which sounds good. The repetition makes it sound like you know what you’re doing and that you are playing ‘wrong’ notes intentionally.
Below is an example of potential side-slipping in a solo:
