Music theory to see, hear and apply.
Maikstrings is a free music theory learning portal from Cuxhaven – from the first note head to the circle of fifths. Every concept is explained with original diagrams and directly applicable on your instrument through three free Android apps.
Whether you're just starting to read sheet music or already building chords and want to understand why they work – you'll find clear explanations without detours. All topics are interconnected: understanding the circle of fifths instantly reveals why certain chord progressions sound so natural. Knowing your intervals changes the way you hear melodies. The interactive diagrams on every page aren't a bonus feature – they're the core. Music theory isn't just something you read; you have to see it and hear it.
One path through music theory – from play to practice
From the first colourful introduction to theory right at the instrument. All three apps are free for Android and work fully offline.
Klang-Regenbogen
A playful first step: colours, sounds and shapes to explore – with no note reading at all. The gentle introduction for the youngest.
Learn more → Ages 10–17Klang-Spektrum
Music theory step by step: reading music, rhythm, intervals, solfège and ear-training exercises – with progress tracking and practice goals.
Learn more → For everyoneCircle of Fifths Auto
Seven tools at the instrument: circle of fifths, chord builder, scales, intervals, waveforms, tuner and metronome.
On Play Store →The seven building blocks music is built from
This guide walks you through the concepts every practising musician keeps in mind – not academically complete, but framed so you can use them at the instrument right away. Each section explains one idea and shows it as a diagram. You don't have to read them in order: jump to whatever you are working on.
The staff & the clefs
Notation captures fleeting sounds permanently. The system has five lines and the four spaces between them. Which note sits on which line is set by the clef at the start of the staff.
The treble clef (G clef) covers the higher registers – guitar, violin, the right hand on piano. Its lines from bottom to top are E – G – B – D – F, the spaces F – A – C – E (the mnemonic "FACE"). The bass clef (F clef) carries the low registers – bass, cello, the left hand on piano.
Accidentals
A sharp ♯ raises a note by a semitone, a flat ♭ lowers it by a semitone, and the natural sign ♮ cancels either one.
Intervals – the building blocks of every melody
An interval is the distance between two notes. Every melody and every chord is a combination of these building blocks. They are counted in letter-name steps: from the unison through the second, third, fourth, fifth, sixth and seventh up to the octave.
There is physics behind the sound. Numbers like 3:2 or 5:4 are frequency ratios: the simpler the ratio, the more the vibrations line up – and the more consonant (calmer) the interval sounds.
- 1:1 unison · 2:1 octave – almost completely merge
- 3:2 perfect fifth – the foundation of the circle of fifths
- 4:3 perfect fourth · 5:4 major third · 6:5 minor third
- 9:8 major second · 16:15 minor second – audibly grating
The emotional code behind it: the major third carries the bright foundation of major, the minor third the pensive colour of minor. The tritone (historically the "devil's interval") creates maximum tension. Familiar melodies make good ear-training cues – the first two notes of the Star Wars main theme, for example, form an ascending perfect fifth.
Scales – the map of notes
A scale is a fixed sequence of whole and half steps within an octave. The major scale follows the same pattern everywhere:
Whole – Whole – Half – Whole – Whole – Whole – Half
In C major those are the notes C–D–E–F–G–A–B–C. Move the pattern to another root and you need accidentals to keep the spacing – which is exactly where the circle of fifths comes in.
The three faces of minor
- Natural minor – the pure relative key (A minor shares all its notes with C major).
- Harmonic minor – the 7th degree is raised so the dominant pulls more strongly to the tonic.
- Melodic minor – the 6th and 7th degrees are raised ascending, natural again descending.
Pentatonics & modes
The five-note pentatonic scale is the workhorse of rock, pop and blues – it almost always sounds right, and the "blue note" gives the blues its rough colour. The church modes create their own moods: Dorian feels mystical, Lydian epic, Phrygian Spanish-oriental.
Chords – notes stacked on top of each other
When at least three notes sound together, you get a chord. The simplest is the triad: root, third and fifth – that is, two thirds stacked on top of each other. Which thirds you stack determines the character:
| Type | Build (semitones) | Character |
|---|---|---|
| Major | 4 + 3 | bright, stable |
| Minor | 3 + 4 | soft, dark |
| Diminished | 3 + 3 | tense |
| Augmented | 4 + 4 | floating |
Inversions, seventh chords, progressions
- Inversion: the same chord with a different note in the bass – C–E–G becomes E–G–C. Makes transitions smoother.
- Seventh chord: a fourth third on top creates the full sound of jazz and blues (Cmaj7, C7, Cm7).
- Chord progressions: the famous four-chord progressions (I–V–vi–IV) are simply walks through the seven diatonic chords of a key.
The circle of fifths – the map of Western music
The circle arranges the twelve notes so that every step around it equals exactly one perfect fifth (seven semitones). Start on C, count seven semitones up and you reach G; on to D, A, E, B, F♯ – until twelve steps later you return to C. This one rule organises a surprising amount of practical knowledge.
Read off key signatures
Each clockwise step adds a sharp, each counter-clockwise step adds a flat. C major: no accidentals. G major: one ♯ (F♯). D major: two ♯ (F♯, C♯). You never have to count them out again.
Relative keys
The inner ring shows the relative minor of each major key with the same key signature. C major and A minor share all seven notes – only the home note differs.
Neighbours harmonise
Directly neighbouring keys differ by just a single note. A song in C can borrow chords from G (a fifth higher) or F (a fifth lower) and still sound coherent.
The seven diatonic chords of a major key
Stack thirds on each note of the scale and you get seven chords that belong naturally to the key. In C major:
| Degree | Chord | Function |
|---|---|---|
| I | C major | Tonic – the home chord |
| ii | D minor | sets things in motion |
| iii | E minor | colour chord, often a substitute for I |
| IV | F major | Subdominant – the lift |
| V | G major | Dominant – pulls strongly back to I |
| vi | A minor | relative minor – the most common substitute for I |
| vii° | B diminished | tense, leads to I |
The classic four-chord progressions – I–V–vi–IV, I–vi–IV–V, ii–V–I – are simply walks through these seven chords.
Rhythm – the pulse of music
Rhythm structures time. Each note value halves the next larger one: a whole note equals two halves, four quarters, eight eighths, sixteen sixteenths. Rests are the silence between – just as important as the notes.
Time signatures
- 4/4 – the driving standard of rock and pop.
- 3/4 – the swinging waltz.
- 6/8 – flowing, felt in two groups of three.
- 5/4, 7/8 – odd time signatures for tension in jazz and progressive rock.
Groove through displacement
Syncopation and off-beats stress the weak beats – the principle behind reggae, funk and ska. Practising with the click on 2 and 4 instead of every beat trains exactly that feel.
Ear training – consonance made visible
Your most important tool is your ears. Relative pitch – recognising intervals in relation to each other – can be learned by anyone with a little training; you don't need "perfect pitch".
Why does a fifth sound pure and a minor second grating? It comes down to the frequency ratios. For a perfect fifth (3:2) the combined waveform repeats cleanly and regularly. For a minor second (16:15) the frequencies sit so close together that the waves interfere – producing audible beating.
That is exactly what the app's animated waveforms make visible: you train your eye to confirm what your ear hears. In ear training, start with just perfect fifths and octaves, add thirds and sixths once those feel secure – five minutes a day adds up quickly.
Practical helpers – right in the browser and in the app
In the practice room you need pragmatic tools that just work. The metronome and tuner run locally via the Web Audio API (the tuner also uses the microphone via getUserMedia) – without any audio data leaving your device.
Precision metronome
40–240 BPM, time signatures 2/4, 3/4, 4/4 and 6/8, accent on beat "1", optional triplets and sixteenths. A visual pendulum for the eye, a precise click for the ear.
Chromatic tuner
Pitch detection via the YIN algorithm – stable even with vibrato and overtone-rich strings. Standard tuning E–A–D–G–B–e is detected automatically.
BPM tap counter
Tap along with the beat and the tempo is calculated instantly in beats per minute – ideal for quickly working out the speed of a song.
Frequency & pitch calculator
Shows which frequency in hertz belongs to which note. Concert pitch A4 is 440 Hz by default – defined in the standard ISO 16.
Common terms in one place
A quick reference for the terms that come up most often on this page and in the app – meant for skimming, not for reading through.
- Tonic
- The home note of a key – the note a melody resolves to. In C major the tonic is C.
- Dominant
- The fifth degree (V). The dominant chord pulls back most strongly to the tonic.
- Subdominant
- The fourth degree (IV). Leads away from the tonic and builds moderate tension.
- Relative key
- The minor key with exactly the same notes as a major key. C major and A minor are relative keys.
- Enharmonic
- Two names for the same pitch – F♯ and G♭ sound identical but are notated differently depending on the key.
- Diatonic
- Belonging to the seven notes of a key. A chromatic chord borrows notes from outside it.
- Triad
- A three-note chord made of two stacked thirds: root, third, fifth.
- Inversion
- The same chord with a different note in the bass. C–E–G is root position, E–G–C the first inversion.
- Cent
- Unit of pitch deviation: 100 cents per semitone. A problem becomes audible from about 5–10 cents.
- BPM
- Beats per minute. 60 BPM = one beat per second. Andante is around 76–108, Allegro 120–156.
- Time signature
- Two numbers at the start of a piece. Top: beats per bar. Bottom: which note value gets one beat.
- B and H
- In German, B is written H and B♭ is written B. Useful when reading German-language sources.
Five ways to use the app in your weekly practice
The features only help if they get used. Here are concrete routines our users have shared – mix and match them with whatever you are already working on.
Five-minute warm-up
Pick a random key on the circle each morning. Play its scale up and down, then arpeggiate its I, IV and V chords. Two minutes in, your fingers are awake and your ears are oriented in that key. Rotate keys clockwise around the circle over the week.
Ear-training drill
Open the interval view, set audio playback to random, and try to name each interval before tapping to reveal the answer. Start with just perfect fifths and octaves; add thirds and sixths once those feel automatic. Five minutes a day adds up quickly.
Chord-by-chord transcribe
Pick a song you like. Find its key on the circle and write down the seven diatonic chords it has available. Most pop songs use only three or four of them – with the cheat sheet in hand, transcribing by ear becomes a process of elimination, not guesswork.
Tempo ladder
Play a tricky passage at 60 BPM, three times clean. Bump to 66, then 72, then 80. The moment you make a mistake, drop back two steps. The metronome plus this rule will land you at performance tempo faster than any "just play it faster" advice.
Waveform listening
Play two notes a fifth apart and watch the combined waveform settle into a clean repeating pattern. Then play two notes a tritone apart and watch the same display flicker. You are training your eye to confirm what your ear is hearing – consonance and dissonance, made visible.
Songwriting walk
Open the circle, pick a major key and write down its seven diatonic chords. Choose four of them in any order – that is your verse. Reorder the same four for the chorus. Add the relative minor for the bridge. You now have a full song structure built entirely from one key.
Frequently asked questions
If you are evaluating whether the app fits your needs – or how to get the most out of a feature – these are the questions we hear most often.
Do I need to know how to read music to use the app?
No. Every view shows the same information in multiple ways: chord symbol, scale degree, note names on the staff and tablature-style fingering charts for guitarists. You can pick whichever representation makes sense to you today, and pick up the others gradually as they start to feel familiar.
Does the app work without an internet connection?
Yes. After the one-time download from Google Play, every feature works fully offline. There is no account, no cloud sync and no login. The tuner uses your microphone locally; the metronome generates audio locally; the chord and scale data ship inside the app. The only thing that requires a connection is the optional Play Store update.
How accurate is the chromatic tuner?
The tuner runs the YIN algorithm at a sample rate of 44.1 kHz and reports deviation in cents. Under normal practice conditions (a quiet room, a clearly plucked note) it resolves the pitch to roughly one cent – well below what a trained ear can hear. Heavy vibrato, strong distortion or a very noisy environment can reduce that precision, but the algorithm is specifically designed to stay stable on the rich overtone content of plucked and bowed strings.
Which instruments is the app suitable for?
The chord builder and scale views are instrument-agnostic and work for piano, guitar, bass, ukulele, brass, woodwind and voice. The fretboard fingering charts are specifically designed for six-string guitar in standard tuning (E–A–D–G–B–e); the tuner is chromatic, so it will pick up any pitched instrument or singing voice.
What is the "Special Mode" in the chord builder?
Special Mode lets you enter any combination of notes – even unusual ones that do not match a standard chord shape – and the app suggests the most likely chord name (with inversions and slash-chord interpretations where relevant). It is the tool you reach for when you have an interesting voicing on the instrument and want to know what to call it on paper.
Can I export chord charts for my own practice sheets?
Yes. Every chord view has an export button that produces either a PDF (good for printing) or a square PNG image (good for sharing). The export includes the chord name, common aliases, the formula, the notes spelled out, the intervals from the root, a short description and the fingering chart. Teachers use this to build per-student handouts in a few minutes.
The app is free – how is it funded?
The Android version is supported by occasional, unobtrusive advertising. There is no paid subscription, no "pro" tier behind a paywall, and no harvesting of personal data. The aim is to keep music theory tools accessible to everyone, including students and hobbyists who would otherwise have to buy a stack of expensive books to cover the same ground.
Which languages does the app support?
Six languages: German, English, Spanish, French, Japanese and Chinese. The translation covers the entire interface as well as chord and interval descriptions. Music theory itself uses international notation (C, D, E… / do, re, mi… / 1, 2, 3…), so the symbols on screen stay consistent across all six versions.
Is this app suitable for teachers?
It is widely used by private music teachers as a reference and demonstration tool during lessons, particularly for students at the "beginner moving into intermediate" stage. The exportable chord and scale sheets are the most popular feature in lesson contexts: a quick PDF takes the place of writing the same chord chart out by hand for the fifth time.
What's New?
Version 1.3 – Highlights
- Animated waveforms for every note and interval
- Interval view with semitones, function and audio example
- Circle of fifths fully interactive – 24 keys, detail popup
- Chord builder with 30+ types and alias display (e.g. C6 ∼ Cadd13)
- "Special" Mode for custom voicings
- Guitar voicings sorted by difficulty
- Metronome and chromatic tuner integrated
- 6 languages fully translated
Available languages
Earlier Apps
Simpler predecessor apps with basic features around the circle of fifths and capodaster. A selection of earlier apps – the complete list can be found under About.
Circle of a fifth Pro
Ad-free Pro version of the circle of fifths. All 12 major and minor keys, key signatures and relative keys.
On Play Store →Chord Circle
Chord diagrams and diatonic chords for all keys. Simple overview tool.
On Play Store →Chord of a Circle Pro
Pro version of Chord Circle – chord diagrams without ads.
On Play Store →Capodaster Sheet Pro
Capodaster transposition tables for guitarists. All chord shapes on all frets.
On Play Store →Circle of fifths +
Simple version of the circle of fifths for a quick overview.
On Play Store →Ad Earnings Service & More
Reporting tool for Android developers. Ad revenue and statistics at a glance.
On Play Store →Hands-on theory – free for Android
Try the circle of fifths, scales and chord finder right in your browser, or download the app. No account, no sign-up, fully offline.