cli_tuner

CLI microphone tuner for bouzouki, tzouras, baglama and classic guitar in Rust.

cli_tuner listens to your default system microphone, estimates the played pitch in real time, and prints the nearest target string with the cents offset.

Features

• Supports tetrachordo tuning: C3 F3 A3 D4
• Supports trichordo tuning: D3 A3 D4
• Supports classic-guitar tuning: E2 A2 D3 G3 B3 E4
• Uses the default system microphone
• Prints the nearest target string, frequency, and cents offset
• Supports adjustable concert A reference with --reference
• Can print tuning targets without opening the microphone via --list

Requirements

• Rust and Cargo installed
• A working input microphone
• Microphone permission granted to your terminal app on macOS

Check your Rust toolchain:

rustc --version
cargo --version

Installation

Clone the repository and build it:

git clone https://github.com/thrasos/cli_tuner.git
cd cli_tuner
cargo build --release

Run the release binary directly:

./target/release/cli_tuner --tuning trichordo

You can also run it without a release build:

cargo run -- --tuning trichordo

If you have cargo installed, install with:

cargo install cli_tuner

If you are on a mac, Install from Homebrew:

brew tap thrasos/tap
brew install cli-tuner

How To

1. Tune your instrument in a quiet room.
2. Place the microphone reasonably close to the instrument.
3. Start the tuner with the tuning preset you want.
4. Pluck one string or course at a time.
5. Read the output: detected frequency in Hz, nearest target string, cents offset, and whether to tune up, tune down, or hold the note as in tune.

Example output:

312.88 Hz | D4     high Re  | +109.7 cents | tune down
294.22 Hz | D4     high Re  |   +3.3 cents | in tune

If the output says tune up, the detected pitch is flat.

If the output says tune down, the detected pitch is sharp.

Supported Tunings

tetrachordo

• C3
• F3
• A3
• D4

trichordo

• D3
• A3
• D4

classic-guitar

• E2
• A2
• D3
• G3
• B3
• E4

Usage

Show help:

cargo run -- --help

Start the tuner with tetrachordo:

cargo run -- --tuning tetrachordo

List string targets without opening the microphone:

cargo run -- --tuning trichordo --list

Classic guitar example:

cargo run -- --tuning classic-guitar

Use a different concert A reference:

cargo run -- --tuning classic-guitar --reference 442

Command-Line Options

• --tuning, -t: Selects the tuning preset
• --reference, -r: Sets concert A in Hz, from 400 to 490
• --list: Prints target strings and exits
• --help, -h: Prints help

Notes

• The tuner uses the default system input device.
• Pitch detection is optimized for approximately 70 Hz to 550 Hz.
• Best results come from single notes or courses played clearly, without heavy background noise.

Troubleshooting

No microphone input detected

• Check that your microphone is connected and selected as the default input device.
• Make sure no other app is blocking access to the microphone.
• On macOS, enable microphone access for your terminal in System Settings > Privacy & Security > Microphone.

Pitch jumps or looks unstable

• Move closer to the microphone.
• Reduce background noise.
• Pluck only one string or course at a time.
• Let the note ring clearly before adjusting the tuning peg.

Development

Run the test suite:

cargo test