How to practise improvising over a random chord progression

The exercise this comes from

The drill is older than the app. A guitar teacher, Yonatan Benaroche, sets a student a progression they did not choose, loops it, and has them improvise over it. The point is the part you did not decide: your hands cannot fall into the shapes they always fall into, and your ear has to lead.

Alea Chord Randomizer is that exercise, automated. It rolls a short progression, loops it at your tempo, and leaves you to play. Everything below is a way of aiming the exercise at something you actually want to get better at.

Your first session, in about a minute

1. Open the app. It comes up with a fresh progression already rolled, so there is nothing to set up first.
2. Press ROLL (or the R key) if you want different chords.
3. Press play (or the spacebar).
4. Play over it on your instrument.

That is the whole loop. The chords sound through the built-in synth, so you do not need a DAW, an interface, or any routing to start.

Two controls decide how much room each chord gets: BARS gives each chord one, two or four bars, and the tempo readout in the header sets the pace. Four chords at one bar each is a fast-moving exercise. Two chords at four bars each is a vamp you can settle into and really explore.

Aim the difficulty at your actual level

The CHORDS panel decides what the dice can roll, and this is where the exercise gets its shape.

CHORD TYPE moves the whole vocabulary at once: TRIADS, 7THS or 9THS. Start on triads if the goal is fretboard or keyboard fluency, move to sevenths when you want to hear guide tones, and reach 9THS when you want the harmony to genuinely challenge you.

Simplify keeps the roots guitar-friendly, which is on by default and worth leaving on for a while. Turn it off and the full 21-root vocabulary opens up, spellings like Gb and D# included, which is its own reading exercise.

Add sus brings sus2 and sus4 chords into the pool for progressions that refuse to resolve the way you expect.

NUMBER OF CHORDS runs from one to eight. One chord is not a mistake: a single chord looping is a modal practice tool, and it is the shortest path to actually hearing what you are playing.

Stay in one key when that is the point

Random chords from anywhere are a good workout for the ear and a bad workout for anything else. When you want to practise phrasing, or lines over changes that behave, turn Key lock on and pick a key and a scale: major, minor or harmonic minor.

Every roll then stays inside that scale, spelled the way a musician would write it. Harmonic minor is worth a session on its own, because the chords it produces are unusual enough to be interesting and still entirely diatonic.

Keep the chords that are working

Two controls turn a lucky roll into a practice piece.

The small dot at the top right of each card is a pin. Pin a chord and it survives every roll that follows, so you can keep the two chords you like and reroll the rest until the progression feels right.

AUTO rolls for you every few loops, with the EVERY selector deciding the cadence. This is the setting that makes a long practice session work: you never stop playing to press a button, and the harmony keeps arriving whether you are ready or not.

Every past roll lands in HISTORY along the bottom. Click one to bring it back, so a progression you played well is never more than one click away.

Two workouts hiding in the same window

The app has two practice modes that are opposites of each other, and both are worth knowing.

The theory workout: drag the window shorter until the MONITOR keyboard tucks away. You still see the chord names, but the notes are hidden, so you have to find them yourself. This is chord spelling under time pressure, which is exactly the skill that makes sight-reading changes possible.

The ear workout: press E, or turn it on from the menu in the top right corner. Now the opposite is true. The chord names disappear behind a crossed-out eye, the keyboard stays dark, and the loop keeps playing. Name what you hear, then click the eye on that card to check yourself. The sounding card keeps its highlight throughout, so you always know where you are in the loop, you just do not know what it is.

Practising with the rest of your setup

If you would rather hear the progression through your own instruments, set OUT to any connected MIDI device, or load the plugin in your DAW and route it to an instrument track. The MIDI routing guide covers that step for each major DAW.

CLICK in the header adds a metronome with its own volume, and the click accents chord changes, which helps when the progression is long enough to get lost in.

Where to take it next

The Chord Randomizer gives you harmony to play over. Alea Scale Shifter, the other instrument in the suite, does the same thing for melody: it streams a line from a scale you choose and slowly morphs it toward another, so the ground moves under you while you play.