Theory quick start (4 minutes).



This guide won’t cover theory per-se. Interactive content instead presents theory (such as our blog content). This guide covers what support is built into emuso for visually reminding you of intervals, for discovering relationships between chords and scales, chords and chords, and scales and scales, using mouse interactions on-“instrument”, using the “clock instrument” and using the “Rel-X” tool.

What you will learn

Notes (circles) on instrument can display interval information, or note names. A colour scheme is used to denote the interval, by colouring the rim of the note’s circle. You’ll learn about these next. You’ll learn how to set up your own colour scheme. Then you’ll learn how to use the clock-instrument, which effectively collapses all notes on instrument onto clock times 0 AM to 11 AM, and finally you’ll learn how to use Rel-X which lets you visually discover chords found in scales, chords found in chords, and scales found in scales.

Visual representation of intervals

This next interaction creates a block of 16 notes along the bass E string (6th string), starting at the anchor located at fret zero.

  1. Notice the notes are labelled 0 to 15 starting at the anchor at fret 0, as these notes are various semitones ABOVE the anchor note. The absolute semitone distance from the anchor to the note is shown in the label. Adjacent frets on the same string produce notes that are a semitone apart.
  2. Click”Reroot” on the interval and pitch strip. Left click on the note at fret 12 on the bass string. This note is now the anchor. Interval distances are now measured from the anchor here.
  3. Notice the labelling is now showing negative values below fret 12, as these notes are various semitones LOWER than the anchor note
  4. Click “Toolkit” and click on the “Octave” button. Dim red circles appear at all octaves of the anchor.
  5. CTL-left click on each of these dim red circles, to relocate the anchor. Since this is a scale fragment laid out along one string, some of the fragment may “fall-off” the string. Notice the labelling each time.
  6. Click “Toolkit” to turn it off. The scale fragment present on entry to the Toolkit is restored.

When improvising, we never think of semitones above or below. This next interaction shows a different form of labelling … “semitone distance from the nearest lower octave of the anchor“. When improvising, we want to be aware of this, though in a slightly different form (“location of interval symbol from the nearest lower octave of the anchor“) coming up shortly.

Make sure you have exited the Toolkit before you try this.

  1. Notice the labelling is now showing values in the range 0 to 11, showing the semitone distance from the nearest lower octave of the anchor (12 semitones lower). This is visually obvious if you look at frets 11,12 and 13. In other words, we can identify a particular note within an octave of the nearest lower anchor, such as “3”, being the 3rd semitone above the start of that octave.
  2. Click “Reroot” and left-click on the 9th fret of the 3rd string. The anchor is now there , The labelling is unaffected.
  3. Left click on the 9th fret and the 10th fret of the 3rd string, creating notes there, including a note at the anchor at the 9th fret.
  4. Left-drag the anchor and watch what happens. The labelling is always relative to the anchor.
  5. Left-drag the anchor towards the bass string, and observe how the scale fragment “falls off”, and reappears when you Left-drag the anchor towards the treble string.
  6. Type “i” (lower case) three times, until you see labels like “b3”, “b5” appear on the notes. “b3” is the theoretical symbol for a note 3 semitones above the nearest lower anchor. “b5” equates to a note 6 semiones above the nearest lower anchor.
  7. Left-drag the anchor again. Observe how the same symbols appear relative to the nearest lower anchor.

Now let’s look at a scale. You’ll be asked to select (right-click) all the “b3″s that you can see.


You can choose how you want notes to be labelled on-instrument. At a minimum, the note can be set to black with a white rim (no information).

Emuso uses a colour-scheme to denote different intervals. The note can appear black with coloured rims (a slight reminder of the intervals). Additional information can be presented withing the note’s circle.

  • semitones
  • absolute semitones
  • interval symbols per octave
  • note names

You can switch between these, repeatedly pressing “i” (make sure the mouse is in the same pane as the instrument). The labelling you need to become familiar with is “interval symbols per octave”, as you practice learning scales and chords.

You can also use “=” to switch between semitones in the range 0 – 11. and interval symbols per octave.

For example, here you will see how the same interval “b3” occurs both in the scale and a chord found in that scale. Knowing this, you can think “I’ll land on the b3 when improvising with this scale over this chord”. After a while, you just know this is a good landing note without especially thinking it’s a b3. But, during directed practice, you absolutely must recognise it is a “b3”, for example.

Using the mouse and ALT- key for basic chord and scale discovery

You can move the mouse over a scale note, with no mouse button held down, but wth the ALT key held down, and have the notes of a chord highlighted, rooted at that scale note.  There may be more than one highlighted note on a string, as this support shows some locations that can supply the chord notes, as opposed to showing chord voicings.  This useful when think about chord tones found in a scale shape.

As an example, here is an interaction that creates a “Dorian” scale.

  1. Set the Play Selected Style tool to “Harmonic”.
  2. Hold down the ALT key and move the mouse over each of the scale notes in turn, and watch and listen. This shows three-note chords (triads).

You can get emuso to create from four to seven note chords instead.

  1. Select “Essentials > Generated Chord Complexity…” from the menu bar at the top-left of emuso

Chord and Scale theory reimagined

Theory details what intervals make up a chord or a scale. This can be visualised using emuso’s clock-instrument, independently of musical instrument, to understand the intervals involved. You effectively look at one or more octaves of pitches, all collapsed onto the the twelve hours (0 AM to 11 AM) of the clock face. Replicating these intervals on a musical instrument involves selecting these intervals from the anchor, and placing them in various octaves … this is what you need to know for performance, and what emuso’s chord and scale libraries do for you. But this is a lot more detail than required to understand the note relatonships between chords and scales, chords and chords, and scales and scales.

Let’s take a look…


Now let’s have a look at the Rel-X tool.  Don’t worry about the scale and chord names used below.  Pay attention to the graphics discussed below.

Here is what Rel-X looks like when you follow steps 1 to 8 below (click it to enlarge (make the lesson fullscreen first)).



After step 2, the clock shows the intervals of the mixolydian scale. Its start note (also known as the tonic) is aligned at 0 AM.   After step 5, a set of twelve dim, coloured spokes appear, initially empty.

On completing step 8,  the chord’s intervals appear on the spokes, with the chord root also aligned  with the scale start note (0 AM).  The spokes at 0, 5 and 7 AM are lit up indicating the intervals found in the sus4 chord, relative to the chord root.  Where a chord note matches a scale note, the spoke shows orange, so you can see this chord exists in the scale, when rooted at the scale start note.

The “Rotate” buttons can be used to move the chord root aganst the scale, to see if it matches elesewhere in the scale.


  1. CTL-left click on the 3rd fret of the bass string to move the anchor.
  2. Press “Toolkit”, click “Scale” and select “Mixolydian”.
  3. Click button “Large clock…” near top right of emuso.
  4. Now we’re going to look for any “sus4” chords that exist in this scale …
  5. Click “Rel-X” at the top right of the large clock.
  6. Click on the dropdown arrow next to the button labelled “by marker click”
  7. Choose “from Chord menu”. Notice the button changes color to orange, as does the Chord button in the Toolkit, to remind you that any chords will be sent to Rel-X, and not the instrument.
  8. Click on the Chord button in the Toolkit and select “sus 4”. (The “sus 4” chord is made up of interval symbols 1, 4, and 5, or semitones 0, 5 and 7)
  9. Type “=” so the labelling changes to semitones in range 0 – 11.
  10. Notice the spokes at times 0, 5 and 7 have all lit up orange. This shows the intervals for the chord are found if the chord is built starting at the scale start note (0 AM).
  11. Click “Rotate+” on Rel-X. The spokes rotate by one position. None light up orange. The scale does not have the right intervals to build a sus4 chord there.
  12. Click “Rotate+” again. The spokes rotate so the chord root aligns with the second note of the scale (at 2 AM). The spokes light up. We have a match.
  13. Keep rotating. You’ll find another match at 5 AM.
  14. You’ve found that the sus 4 chord can be built rooted at the scale pitches located at 0, 2 and 5 semitones above the scale start note.

Now let’s look for a scale called “major pentatonic” (its semitone intervals are 0 2 4 7 and 9).

  1. Click on the dropdown arrow next to the button labelled “by marker click”
  2. Choose “from Scale menu”. Notice the button changes color to orange, as does the Scale button in the Toolkit, to remind you that any scales will be sent to Rel-X, and not the instrument.
  3. Click on the Scale button in the Toolkit, scroll down, and select “Major Pentatonic”. (This has semitone intervals 0 2 4 7 and 9)
  4. Notice that the spokes at times 0 2 4 7 and 9 all light up orange. So, the mixolydian scale contains this pentatonic, starting at the first note of the mixolydian scale.
  5. Keep rotating, and you will find matches at times 5 and 10 as well. The pentatonic can be built from the mixolydian scale pitches located at times 0, 5 and 10.

Scales that are “roughly” right for a chord are often used for aural effect. Rel-X can be used for this, and also to find chords within chords.

Changing the colour scheme for intervals

The “Colour picker” tool (shown below, click to enlarge (when the lesson is full-screen)) lets you choose colours for the different intervals.

It appears comes up when you select “emuso > Interval colours…” from the menu bar at the top left of emuso. It can be repositioned by left-dragging the mouse anywhere in its black background. Notice how the colours shown on the tool match the colours shown on the pitch and interval strip, and the colours used on notes on the instrument.


Let’s change the colour of the interval b3.

  1. Select emuso > Interval colours…
  2. Enter the Toolkit, and choose “Min Triad” from the Chord menu
  3. Click on the button labelled “b3” in the picker.  Its appearance changes.
  4. At the bottom right of the picker, click on the drop down arrow showing next to label “White”.  A colour palette appears.
  5. Choose a colour, and watch how the circle rim on the note labelled “b3” changes to match, as does the interval strip’s “b3” colour.
  6. If you want to change the colour of the anchor when its unoccupied, use the “Anchor” button in the picker to do this.
  7. Use “Reset” in the picker to revert to the colour schem emuso comes with.


What you have learned

You’ve learned that an interval is formed by two notes, whose sound flavour is unique to the number of semitones between the two notes, and all chords and scales are made of combinations of these.  The flavours range from stable to very clashy, more or less so depending on their occurrence in the rhythm.  Clashes can add ear candy.  If you learn intervals based on note names, that is far harder, much more to remember.  For example, to play 3 semitones starting at any note anywhere on the guitar, play the note, and play the other note 3 frets higher (towards the body) on the same string.  By note name:  play A and C.  Bb and Db. B and D etc.  Intervals based on semitones, and shapes, plus knowledge of the theory based names, drastically reduces the memory load.  Note names are far less significant.

You’ve learned that typing “i” repeatedly changes the labelling of notes, with options for semitones in the range 0-11, interval symbols (e.g. “b3”), unrestricted semitones, and note names.  Type “=” to switch between semitones in the range 0-11 and interval symbols.

You then learned that the clock-instrument collapses all octaves from the anchor into one 12-semitone block, with time 0 corresponding to the note the anchor is located at, and all of its octaves, above and below the anchor.  Similarly, time 3 (as an example) corresponds to the note 3 semitones above the anchor, and all of its octaves, above and below the anchor.  The clock always reflects the current occupied locations on-instrument.

Finally you learned about the Rel-X tool which lets you load the intervals of a chord or scale (collapsed into one 12-semitone block), visualised on 12 spokes. The chord is initially visualised rooted at the anchor.  The spokes can be rotated, so the chord’s root aligns against different semitone distances from the anchor … that is, rooted at that semitone distance form the anchor.  Visually, matches can then be detected, as in the example above, where you saw a sus4 chord match the notes of the mixolydian scale when rooted at the anchor note, and at 5 and semitones above the anchor.  Creating the chord on-instrument is a matter of choosing these intervals, in various octaves if you want.  Similarly, scales can be searched for, using Rel-X.


You’ll learn about the help system built into emuso, which includes videos that can be activated from clicking on menu items and buttons and so, explaining what these do.  The help system also includes user-guides.

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