String Tuner

"String Tuner" is a simple, highly precise, and ultra-responsive real-time tuning app designed exclusively for stringed instruments.

With support for acoustic guitar, electric guitar, bass, ukulele, violin, viola, cello, double bass, and banjo, this app is all you need to tune your instrument quickly and accurately.

🌟 Key Features
1. Ultra-Responsive & High Precision
- Optimized Pitch Detection (FFT & YIN): By leveraging Cooley-Tukey Fast Fourier Transform (FFT) and the YIN autocorrelation algorithm, the app minimizes processing latency. Experience a buttery-smooth, lag-free tuning needle that responds the exact instant you pluck a string.
- Cents-Level Accuracy: The needle and numeric values show the exact offset in cents. When you are in tune (within ±3 cents), the screen glows green and triggers a haptic pulse for instant confirmation.

2. Intuitive Adjacent Note Indicator
- Unfamiliar with the CDEFGAB note notation? No worries! The app displays adjacent notes (e.g., • C4 • D4 • [E4] • F4 • G4 •) around the currently detected pitch. You can immediately see the relative position of the tone, making it easy to understand whether to tighten or loosen the string.

3. High-Audibility Reference Tone (Harmonic Synthesis for Low Bass)
- Tired of not being able to hear low bass notes (E1, E2) through your phone's small built-in speaker? String Tuner implements the "Missing Fundamental" psychoacoustic phenomenon.
- By synthesizing 1st to 6th harmonics, your brain naturally reconstructs the deep fundamental pitch. You can easily hear and tune to reference pitches, even for low-frequency instruments.

4. Multilingual & Instrument Library
- Guitar (E2 - A2 - D3 - G3 - B3 - E4)
- Bass (E1 - A1 - D2 - G2)
- Ukulele (G4 - C4 - E4 - A4)
- Violin (G3 - D4 - A4 - E5)
- Viola (C3 - G3 - D4 - A4)
- Cello (C2 - G2 - D3 - A3)
- Double Bass (E1 - A1 - D2 - G2)
- Banjo (G4 - D3 - G3 - B3 - D4)

5. Offline & Privacy-First Design
- All mic inputs are processed locally on your device in real-time. No audio data is ever stored, saved, or uploaded to any external server. Tune with peace of mind anywhere, even without internet access.

⚙️ App Permissions
- Microphone (RECORD_AUDIO): Used solely to detect your instrument's pitch.
- Internet (INTERNET): Used solely for ad delivery via Google AdMob.

Achieve perfect pitch in seconds. Download String Tuner today and experience the ultimate lag-free tuning!

Recent changes:
* Improved Real-Time Tuning: Significantly enhanced microphone responsiveness and pitch detection speed for smoother, real-time tuning.
* Optimized Low-Pitch Detection: Upgraded the algorithm to recognize low-frequency pitches (such as E2 on the guitar) accurately and quickly.
* Intuitive Note Indicator: Added a guide displaying adjacent notes on both sides of the detected pitch, making it easier to understand your current tuning even if you are not familiar with CDEFGAB notation.