톤 생성기 - 오디오 주파수 & 파형 생성기 온라인

// Using the Web Audio API to generate tones in the browser

function playTone(frequency = 440, waveform = 'sine', volume = 0.5) {
  const ctx = new AudioContext();
  const oscillator = ctx.createOscillator();
  const gainNode = ctx.createGain();

  oscillator.type = waveform; // 'sine', 'square', 'sawtooth', 'triangle'
  oscillator.frequency.setValueAtTime(frequency, ctx.currentTime);
  gainNode.gain.setValueAtTime(volume, ctx.currentTime);

  oscillator.connect(gainNode);
  gainNode.connect(ctx.destination);
  oscillator.start();

  // Return stop function
  return () => {
    gainNode.gain.linearRampToValueAtTime(0, ctx.currentTime + 0.05);
    setTimeout(() => {
      oscillator.stop();
      oscillator.disconnect();
      ctx.close();
    }, 50);
  };
}

// Convert frequency to musical note name
function frequencyToNote(frequency) {
  const A4 = 440;
  const noteNames = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#', 'A', 'A#', 'B'];

  const semitones = 12 * Math.log2(frequency / A4);
  const roundedSemitones = Math.round(semitones);
  const cents = Math.round((semitones - roundedSemitones) * 100);

  const noteIndex = ((roundedSemitones % 12) + 12 + 9) % 12;
  const octave = Math.floor((roundedSemitones + 9) / 12) + 4;

  return { note: noteNames[noteIndex] + octave, cents };
}

// Example usage
const stop = playTone(440, 'sine', 0.5);
console.log(frequencyToNote(440));    // { note: 'A4', cents: 0 }
console.log(frequencyToNote(261.63)); // { note: 'C4', cents: 0 }
setTimeout(stop, 2000);