Perfect Pitch: Unveiling the Mathematical Symphony Behind a Guitar Tuner

How do you find a clean musical note in a noisy signal? Discover the algorithm that compares a sound wave to itself to find perfect pitch.

#1about 3 minutes

Building an open source guitar tuner with Javascript

The project was created out of curiosity to understand the mathematics and algorithms behind pitch detection using React and Next.js.

#2about 3 minutes

Understanding the relationship between notes and frequency

Every musical note corresponds to a specific frequency, and an octave represents a doubling of that frequency.

#3about 4 minutes

Comparing different pitch detection algorithms

While Zero Crossing and FFT have limitations with noisy signals, autocorrelation effectively finds repeating patterns to isolate the fundamental frequency.

#4about 1 minute

Accessing microphone audio with browser APIs

The MediaStream API captures microphone input, and the Web Audio API's AnalyserNode provides real-time audio data for processing.

#5about 3 minutes

Setting up the audio processing pipeline

The implementation involves getting the media stream, creating an audio context, connecting an analyzer, and storing the signal in a Float32Array buffer.

#6about 3 minutes

Translating the autocorrelation algorithm into code

The implementation normalizes the audio buffer using Max Absolute Scaling, filters noise with Root Mean Square, and then applies the autocorrelation formula.

#7about 4 minutes

Converting autocorrelated data into a musical note

The fundamental frequency is found by identifying the highest peak in the autocorrelated signal, which is then converted into a note name, octave, and tuning offset.

#8about 2 minutes

Creating the user interface with React

The tuner's indicator is built using the react-gauge-chart library, which visualizes the 'cents off' value as a percentage.

#9about 2 minutes

Exploring future improvements for the tuner

Potential enhancements include adding pre-processing noise filters, implementing complex chord detection, and using more accurate algorithms like YIN.