English · Русский
Nine ear-training exercises, and three real effects that explain themselves while they work on your own audio. Free, source available, macOS · Windows · Linux, as VST3 · AU · Standalone.
The desktop build, recorded: open an exercise, answer it, switch theme, switch language.
The browser demo is the same trainer, playable.
Wiki · Discussions · Telegram · Roadmap
Somebody tells you a mix is muddy. You go home, learn that mud lives around 250–400 Hz, sweep a filter through there — and you still cannot hear the thing you are meant to be removing. Only that something changed.
That is not a knowledge problem. Everything worth knowing is already written down, free, a hundred times over. It is a hearing problem, and hearing is a physical skill: it comes from doing one small thing a few hundred times with something telling you immediately whether you got it right. Almost nobody gets that, because building the exercise is harder than doing it.
abcTrain is the exercise, already built — and then the same vocabulary again in three plugins you can put on a real track, so what you practised is what you are now doing.
Who it is for: you mix your own music and can follow a tutorial but cannot hear what it is about; or you have mixed for years and want to stop reaching for −6 dB because it worked last time. Not for you if you want a syllabus and a certificate — there isn't one, on purpose.
Four ask for a value, answered by dragging along a scale. You do not have to be exact — landing inside the tolerance band counts, and landing closer counts for more. The level narrows that band, so harder means more precise, not quieter.
| Exercise | What you are hearing | |
|---|---|---|
| 🎚️ | Find the frequency | Which frequency got boosted or cut, anywhere in 100 Hz – 12.8 kHz |
| Guess the pan position | Where it sits across the stereo field | |
| 🔊 | Guess the gain change | How far the level moved, −9 … +9 dB |
| ⏱️ | Guess the delay time | How long the echo is, 20 – 640 ms |
The other five ask you to name a thing, and always give you exactly two alternatives — at every level, from your first round to your last.
| Exercise | What you are choosing between | |
|---|---|---|
| 🥁 | Guess the compression | Two of: weak · medium · strong |
| 🏛️ | Guess the reverb | Two of: room · chamber · hall · plate · spring |
| 🔥 | Guess the distortion | Two of: soft clipping · hard clipping · tape · overdrive |
| 📐 | Guess the stereo width | Two of: narrow · normal · wide · extra wide |
| 🎯 | Name the range | Two of the seven standard ranges: sub-bass … air |
Never a third button. It would only give you more to read and better odds of a lucky guess. The level changes which two instead: level 1 is a cathedral against a broom cupboard, level 10 is two things that genuinely take work to separate.
Every answer is a family, not a preset. A tiled booth and a big live room are both rooms, and someone who recognises only one of them has not learned what a room sounds like.
Practice is unlimited, Survival gives three lives, Blitz is ninety seconds where a wrong answer costs five of them. Every exercise keeps its own level, because being good at panning says nothing about hearing 400 Hz. Train on pink noise, on the built-in clips, or on your own music.
| Learner EQ | A graphical EQ: up to eight bands of any type — bell, shelf, high-pass, low-pass, notch — added and removed on the curve itself. The spectrum is labelled in sensations as well as numbers: Sub, Bass, Boom, Body, Honk, Presence, Sibilance, Air. |
| Learner Comp | A compressor with a soft-knee engine and a gain-reduction meter that fills downward, because that is the direction the sound goes. Seven training modules, one per control. |
| Learner Verb | Room, hall, plate and spring, with decay, pre-delay, size, damping, mix and width. Seven modules of its own. |
A module is not just a lesson: afterwards the plugin sets the control to a value it does not show you, plays it, and you turn its own knob until it matches by ear.
- Not a course. No syllabus, no certificate, no lesson plan.
- Not a mixing tutor. It trains hearing; what you do with it is yours.
- Not signed. Your system will warn you the first time — see below.
- Not connected to anything. No account, no server, no telemetry. Your progress is a file on your own machine.
- It does not separate stems. Imported music is sorted by measurable character, not by instrument, and it does not pretend otherwise.
Download the latest release — a real installer per platform, built by CI from the exact commit the tag points at.
Your system will warn you, and the warning is honest. These builds are not code-signed: signing means buying a certificate issued against a verified legal identity, roughly $99/year from Apple and $200–500/year from a Windows CA, and that has not been bought. The warning says the publisher is unverified — not that anything was found wrong with the file.
- macOS — right-click the
.pkg→ Open → Open again. - Windows — More info → Run anyway.
- Linux — extract and run
./install.sh.
The Installation page walks through all of it, including install paths and where your progress lives. Or build from source — three commands, and it is the same binary with nothing to click through:
git clone https://github.com/bogggare567/abcTrain.git
cd abcTrain
cmake -B build && cmake --build buildCMake fetches JUCE itself; no separate install needed. On Linux, add
libcurl4-openssl-dev first. Testing and build
detail.
The interface ships in twelve: English, Русский, Deutsch, Français, Español, Português, Italiano, Polski, Українська, 简体中文, 日本語, 한국어. Detected from your system on first run, changeable in the bottom bar.
Honestly: only English and Russian have been checked by a speaker. The
other ten are machine-checked, and a correction is one JSON file in
shared/i18n/strings/ — a genuinely useful pull request. Parameter
tooltips, lesson text and the training modules are still English-only.
| Wiki | The manual, for people using it — install, first ten minutes, every exercise, your own audio, levels, troubleshooting. Also in Russian. |
| docs/orientation.md | The map, for people changing it. Short. Read it first. |
| docs/decisions/ | Every non-obvious choice, with the alternative that was rejected and why. |
| docs/user-journey.md | What this product is for, and the three questions any proposed feature has to answer. |
| CLAUDE.md | Per-file map of the whole repository. |
| You have | Go here |
|---|---|
| a question about using it | Discussions → Q&A |
| something broken | Issues |
| an idea | Discussions → Ideas — start with the problem, not the solution |
| something you made with it | Discussions → Show and tell |
| to hear about new versions | Telegram → @vstabc |
Good first contributions, roughly in order of how self-contained they are:
a translation (one JSON file in shared/i18n/strings/), a new
exercise (seven steps, all in docs/orientation.md),
or anything on the roadmap.
One thing that will bite you if nobody says it: the tests cannot see layout. Every visual pass in this project's history has shipped a bug that compiled, passed all 234 test groups, and was obvious ten seconds after looking at the thing. If you change something visual, render it and look at it.
.github/CONTRIBUTING.md covers how pull requests are shaped here, and there are issue templates for bugs and features.
Copyright © 2026 bogggare567 (soundkorb). All rights reserved.
The source is open to read, and to build for yourself. It is not open to redistribute or to commercialise. Without prior written permission from the copyright holder you may not:
- distribute the software or any build of it, for a fee or otherwise;
- use the source, in whole or in part, in a commercial product;
- sell, sublicense, rent or resell it.
Using it, on your own machine, on your own music, including work you are paid for, is fine and always will be. Full text in LICENSE.
Third-party components — JUCE, and libcurl on Linux builds — stay under their own licences.
Free for you to use, and staying that way: no paid tier, no subscription, nothing locked behind anything. A star helps other people find it; a donation keeps it moving. Neither unlocks anything, because gating a learning tool behind a favour is the opposite of the point.
The rest of this work lives at soundkorb.ru.
ambiance · balance · clarity