This page is written to match the terms and behavior used inside the app (aiming for 0 cents / the default reference pitch A = 442 Hz / the dyad, chord, and rhythm modes).
About this app
Q. What kind of app is harmonize?
It is a training app that develops your sense of pitch — the feel for matching a note to its “correct” height — using your ears and your fingers. You layer the voices of two characters (Ebifurya and Kakifurya) and slide a note up and down to find the position where the beating disappears and the sound becomes clear. There are several modes, including dyads (two notes), chords (three or more notes), and rhythm.
Q. Can I play without any musical knowledge?
Yes. Even without knowing the theory, anyone can feel the change from “muddy” to “clear.” This app is designed to train your ears before your knowledge, by letting you experience the satisfying moment when the pitch locks in, over and over. Treat the glossary in this FAQ as further reading for when you want to dig deeper.
Using the app and settings
Q. Where are the settings? What can I change?
From the settings screen (the settings button on the home screen) you can mainly change the following:
- Sound settings: the timbre (instrument) and volume of Ebifurya / Kakifurya, and the test tone
- Rhythm sound: the timbre, volume, and preview for rhythm mode
- Sound-effect volume / mute sound effects
- Reference pitch A (440–446 Hz)
- Note naming (Do-Re-Mi / C-D-E, etc.)
- Showing the background animation and the speech-bubble guide
- Language (automatic + manual switching)
- Remove ads (in-app purchase) and Support development
- Reset data
Q. What is a “player”?
It is a switchable slot that lets up to three people share a single device (Player 1 / 2 / 3). You can switch between them with the 👤 button on the home screen. It is handy for sharing one device with your family, or for keeping settings and progress separate. If you use the app alone, you can simply stay on Player 1.
Q. What changes (gets separated) when I switch players?
Some things are saved separately per player, and some are shared across all players. Because this is easy to confuse, here is a summary.
Separated per player (swapped when you switch)
- Progress (unlock status and stars for dyads, chords, and the moon stage; best stars in rhythm)
- Timbres (Ebifurya / Kakifurya) and their individual volumes
- Rhythm timbre and volume
Shared across all players (unchanged when you switch)
- Settings such as reference pitch A, note naming, sound-effect volume / mute, background animation, speech-bubble guide, and language
- Purchases (remove ads, the one-time unlocks for the moon stage and rhythm) … once purchased, they are active for all players
So, for example, “Player 2 having 0 stars” does not mean your data was erased — it is simply a separate slot from Player 1. Switch back to your original player with the 👤 button and your progress is right where you left it.
Q. Which player gets erased by “Reset data”? Do I have to buy the purchases again?
Only the progress of the player you currently have selected is reset. The progress of other players is not erased. Also, purchased ad removal and the one-time unlocks for the moon stage / rhythm are kept (you do not need to buy them again after a reset).
Q. The sound effects are too loud. Can I turn them down or off?
Yes. You can adjust them in two stages on the settings screen.
- “Sound-effect volume”: adjust, with a slider, the loudness of effects such as correct, incorrect, applause, and results.
- “Mute sound effects”: turn these effects completely off (button operation sounds remain).
If they feel too loud, first lower the volume; if it still bothers you, mute them.
Q. Can I change the timbre (the instrument sound)?
Yes. Open “Sound settings” on the settings screen and you can choose a separate timbre for Ebifurya and for Kakifurya. You can compare them with the test tone, and the timbre and volume are saved per player. The rhythm-mode sound can be changed separately from “Rhythm sound.”
Q. Can’t I remove the ads?
You can remove them with “Remove ads” (a one-time in-app purchase). Buy it from the settings screen, or from the menu at the top of the screen. Once purchased, you can carry it over after changing or reinstalling your device with “Restore purchase” (the same Apple ID is required). “Support development” is a separate, optional purchase to support the developer, distinct from removing ads.
Q. I want to change the display language.
You can change it from “Language” on the settings screen. Besides “Follow device settings (automatic),” you can choose a language manually. The change takes effect after you restart the app.
Q. I want to change “Do-Re-Mi” notation to “C-D-E,” etc.
You can switch it with “Note naming” on the settings screen. You can choose from English (C D E…), German (C D E…H), Japanese (Ha Ni Ho…), and Italian (Do Re Mi…).
Q. I want to hide the background animation or the hint bubbles.
You can turn each one off / change it individually on the settings screen.
- Background animation: toggle on / off.
- Speech-bubble guide: choose its position from “none / bottom-right / top” (“none” hides it).
Q. I want to start my progress over from the beginning.
You can reset it with “Reset data” on the settings screen. Erased data cannot be undone, so please confirm before doing so.
Q. The app crashes / freezes / makes no sound.
First, please try the following.
- Quit the app once and restart it.
- Check whether your device’s silent (ringer) switch is on (this app is designed to play even while silent, but just in case).
- Update your device to the latest iOS.
- If it still does not improve, let us know via “Rate Harmonize” on the settings screen or via the contact option (it helps if you include your device, iOS version, and the steps to reproduce).
The basics of ear
Q. What is relative pitch?
It is the ability to tell how much higher or lower another note is from a reference note (i.e., the interval). Being able to find “So” after hearing “Do,” for example, comes from grasping the gap between the two notes (a fifth) relatively. The ability at work when you match pitch with others, harmonize, and sing in a choir or ensemble is mainly this relative pitch, and anyone can develop it with training. This is the ability harmonize trains.
Q. What is absolute pitch? How does it differ from relative pitch?
The ability to name the pitch of a single note played on its own, without a reference, is absolute pitch. Being able to immediately tell “that was an A (La)” — having, as it were, the absolute coordinates of sound. Relative pitch, on the other hand, is the ability to grasp the distance between notes; they are different things. Absolute pitch is said to be easier to acquire in early childhood, but what is essentially important for performing and playing together with others is relative pitch, because harmony is determined by the relationships between notes. harmonize focuses on relative pitch (and, beyond it, the ear that hears pure resonance).
Q. Can I still train my ear as an adult?
Relative pitch can be trained. The key is to imprint the correct resonance on your ears again and again. In harmonize, the moment you match, the beating disappears and the cent value approaches 0, making it easy for your body to remember “the matched state.” A little practice every day is the fastest route to improvement.
Temperament — just intonation and equal temperament
Q. What is just intonation?
The way of taking intervals so that the overtones mesh perfectly and no beating occurs — the “purest, clearest” tuning — is called just intonation. When the frequency ratio of two notes becomes a simple whole-number ratio such as 2:3 (a perfect fifth) or 4:5 (a major third), the waveforms overlap periodically and the muddiness disappears. This is pure resonance. The “position where the beating disappears” that you aim for in harmonize is exactly this pure interval.
Q. What is equal temperament? How does it differ from just intonation?
Equal temperament is the tuning method, used in modern pianos and so on, that divides one octave into twelve equal parts. In exchange for never breaking down no matter which key you modulate to, the fifths and thirds are slightly off from pure, so in theory they are faintly muddy.
| Just intonation | Equal temperament | |
|---|---|---|
| Resonance | Beating disappears, clear | Slightly muddy |
| Advantage | Harmonizes, beautiful | Usable uniformly in any key |
| Where used | Choir, strings, winds | Piano, keyboard instruments |
The piano is fixed to equal temperament, but the human voice and string/wind instruments can be nudged toward pure during performance. harmonize trains that sense of “nudging toward pure with your ears.”
Q. Why does harmonize aim for pure resonance?
Because the resonance that truly harmonizes beautifully in ensemble and choral singing is that of just intonation. Even ears accustomed to equal temperament can tell “this one is clearer” when they hear a pure fifth or third. Once you can distinguish that difference, you can make the judgment to nudge notes in actual performance.
Cents and beats
Q. What is a cent?
It is a unit for measuring the fineness of an interval. A semitone of equal temperament is defined as exactly 100 cents, so one octave is 1200 cents. In harmonize, the result screen shown after you commit your answer displays the deviation from the correct pitch in cents, like “+3.2 cents” (the closer to 0 cents, the more spot-on, and getting within a few cents earns you more stars). Think of the matching during play itself as done by ear (beats), with cents being a ruler that tells you how well you matched, after the fact.
Q. What are “beats”? Why do they disappear when the pitch matches?
When the heights of two notes differ slightly, the sound seems to wobble periodically, “wah-wah…” — this phenomenon is beating. The speed of the beating is exactly equal to the difference in frequency of the two notes, so the more the heights line up, the slower it gets, and when they match perfectly it stops and disappears. That is why, in harmonize, “the beating disappears = matched.” The basic cue during play is this ear-based information called “beats” (the number on the screen is the current height, i.e., Hz, and does not directly tell you whether you are matched).
Q. What should I rely on while playing?
The basic approach is to listen for the “beats” with your ears and search for the position where they slow down and disappear. The screen shows the current height in Hz, but this is a guide; what tells you “matched / off” is the beating (your ears). When you commit your answer, the deviation appears on the result screen as a cent value, so cross-check “the feel of the beating disappearing” with “the actual cents” on the results to sharpen your ear’s precision. If you can ultimately match by ear alone, without relying on the on-screen number, that is true relative pitch.
Reference pitch (tuning)
Q. What is reference pitch A? Why is 442 Hz the default?
It is the height of the “A (La)” that orchestras and the like tune to. The default in harmonize is A = 442 Hz. It varies by country, era, and orchestra — 440–446 Hz and so on — and since 442 Hz is widely used by Japanese orchestras, it is the default. You can choose from 440–446 Hz on the settings screen.
Q. What changes when I change the reference pitch?
The absolute height of every note slides up or down (the relationship between intervals — the relative ratios — does not change). Adjust it when you want to practice at the pitch of the orchestra or recording you usually play with. At any reference pitch, the essence of the training — “erase the beats = match to pure” — is the same.
Q. Is it true that old music used a lower pitch than today?
Yes. In the Baroque era and so on, around A = 415 Hz (about a semitone lower than today) was sometimes used. Lower pitches are still used in early-music performance. (Support for lower historical pitches is under consideration as a future expansion.)
Intervals, dyads, and chords
Q. How do the “dyad” and “chord” modes differ?
- Dyad mode: the basic harmony practice of sounding two notes at the same time and matching them.
- Chord mode: a more practical practice handling chords stacked from three or more notes.
The characters (Ebifurya / Kakifurya) each take a voice (part), and you adjust their heights to bring the whole into pure resonance.
Q. What are the root, the third, and the fifth?
They are the names of the “roles” of the notes that build a chord.
- Root: the central note that forms the foundation of the chord.
- Third: the note that stacks above the root and decides whether the chord is bright (major third) or dark (minor third).
- Fifth: the note that blends most clearly with the root and stabilizes the chord.
The third is especially delicate when harmonizing; a pure major third settles beautifully when taken a bit lower than in equal temperament.
Q. What are overtones? How do they relate to harmonizing?
A single note contains many components at integer multiples of its height (overtones). When the overtones of two notes overlap at the same height, the resonance meshes and the beating disappears. This is the true nature of “harmonizing.” It is precisely because the overtones line up at a pure interval (a simple whole-number ratio) that the resonance becomes clear.
Tips for training
Q. I just can’t match it. How should I practice?
- First, listen well to the correct note and let its resonance linger in your head.
- Move the slider slowly and search for the direction in which the beating slows.
- Stop your finger at the position where the beating stops and disappears, and commit your answer there.
- Check the cents (deviation) on the result screen and reconcile it with “the feel of the matched resonance.”
Q. Do I need a quiet environment and earphones?
Because beating is very delicate, we recommend earphones or headphones if possible. You can play with speakers too, but a quiet environment makes the subtle muddiness easier to hear, and you will improve faster.
Q. How do the stars increase?
The higher the precision of your match (the closer to 0 cents), the more stars you get. Because the design trains your ears the more you aim for high precision, don’t be satisfied with just clearing — try aiming for three-star precision.
