 <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Web Synthesizer</title>
    <style>
        /* Stylesheet for the synthesizer */

        body {
            margin: 0;
            font-family: Arial, sans-serif;
            background-color: #333;
            color: #fff;
        }

        .synth-container {
            max-width: 800px;
            margin: 0 auto;
            padding: 20px;
        }

        h1 {
            text-align: center;
        }

        .controls {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-around;
            margin-bottom: 20px;
        }

        .controls label {
            margin-right: 10px;
        }

        .controls input,
        .controls select {
            margin-right: 20px;
        }

        .keyboard {
            display: flex;
            position: relative;
            height: 200px;
            margin: 0 auto;
        }

        .key {
            border: 1px solid #000;
            border-radius: 5px;
        }

        .white {
            width: 60px;
            background: #fff;
            z-index: 1;
        }

        .black {
            width: 40px;
            background: #000;
            position: absolute;
            margin-left: -20px;
            height: 120px;
            z-index: 2;
        }

        .key:active {
            background: #ccc;
        }

        .key.black:active {
            background: #555;
        }

        /* Positioning keys based on notes */
        .key[data-note="C"] { left: 0px; }
        .key[data-note="C#"] { left: 45px; }
        .key[data-note="D"] { left: 60px; }
        .key[data-note="D#"] { left: 105px; }
        .key[data-note="E"] { left: 120px; }
        .key[data-note="F"] { left: 180px; }
        .key[data-note="F#"] { left: 225px; }
        .key[data-note="G"] { left: 240px; }
        .key[data-note="G#"] { left: 285px; }
        .key[data-note="A"] { left: 300px; }
        .key[data-note="A#"] { left: 345px; }
        .key[data-note="B"] { left: 360px; }

        /* Responsive design for smaller screens */
        @media (max-width: 600px) {
            .controls {
                flex-direction: column;
                align-items: center;
            }

            .keyboard {
                transform: scale(0.8);
            }
        }
    </style>
</head>
<body>
    <div class="synth-container">
        <h1>Web Synthesizer</h1>
        <button id="start-button">Start Synth</button>
        <div class="controls">
            <label for="waveform">Waveform:</label>
            <select id="waveform">
                <option value="sine">Sine</option>
                <option value="square">Square</option>
                <option value="sawtooth">Sawtooth</option>
                <option value="triangle">Triangle</option>
            </select>
            <label for="volume">Volume:</label>
            <input type="range" id="volume" min="0" max="1" step="0.01" value="0.5">
            <label for="cutoff">Filter Cutoff:</label>
            <input type="range" id="cutoff" min="100" max="10000" step="1" value="5000">
            <label for="resonance">Filter Resonance:</label>
            <input type="range" id="resonance" min="0" max="20" step="0.1" value="1">
        </div>
        <div class="keyboard">
            <!-- White Keys -->
            <div class="key white" data-note="C" tabindex="0"></div>
            <div class="key black" data-note="C#" tabindex="0"></div>
            <div class="key white" data-note="D" tabindex="0"></div>
            <div class="key black" data-note="D#" tabindex="0"></div>
            <div class="key white" data-note="E" tabindex="0"></div>
            <div class="key white" data-note="F" tabindex="0"></div>
            <div class="key black" data-note="F#" tabindex="0"></div>
            <div class="key white" data-note="G" tabindex="0"></div>
            <div class="key black" data-note="G#" tabindex="0"></div>
            <div class="key white" data-note="A" tabindex="0"></div>
            <div class="key black" data-note="A#" tabindex="0"></div>
            <div class="key white" data-note="B" tabindex="0"></div>
        </div>
    </div>
    <script>
        /* JavaScript code for the synthesizer functionality */

        let audioContext;
        let masterGain;
        let filter;
        let activeNotes = {};
        let isAudioInitialized = false;

        // Map of note frequencies
        const noteFrequencies = {
            'C': 261.63,
            'C#': 277.18,
            'D': 293.66,
            'D#': 311.13,
            'E': 329.63,
            'F': 349.23,
            'F#': 369.99,
            'G': 392.00,
            'G#': 415.30,
            'A': 440.00,
            'A#': 466.16,
            'B': 493.88
        };

        // Initialize audio context after user interaction
        document.getElementById('start-button').addEventListener('click', () => {
            try {
                // Use webkitAudioContext for Safari compatibility
                const AudioContext = window.AudioContext || window.webkitAudioContext;
                audioContext = new AudioContext();

                // Master gain node for volume control
                masterGain = audioContext.createGain();
                masterGain.gain.value = parseFloat(document.getElementById('volume').value);
                masterGain.connect(audioContext.destination);

                // Low-pass filter
                filter = audioContext.createBiquadFilter();
                filter.type = 'lowpass';
                filter.frequency.value = parseFloat(document.getElementById('cutoff').value);
                filter.Q.value = parseFloat(document.getElementById('resonance').value);
                filter.connect(masterGain);

                // Unlock audio on iOS devices with a short beep
                const osc = audioContext.createOscillator();
                osc.connect(audioContext.destination);
                osc.start();
                osc.stop(audioContext.currentTime + 0.01);

                isAudioInitialized = true;
                document.getElementById('start-button').disabled = true;
            } catch (error) {
                console.error('Error initializing audio context:', error);
            }
        });

        // Function to start a note
        function noteOn(note) {
            if (!isAudioInitialized) return;
            if (activeNotes[note]) return; // Prevent duplicate notes

            try {
                const osc = audioContext.createOscillator();
                const gainNode = audioContext.createGain();

                osc.type = document.getElementById('waveform').value;
                osc.frequency.value = noteFrequencies[note];

                // ADSR envelope (attack and release only)
                const now = audioContext.currentTime;
                gainNode.gain.setValueAtTime(0, now);
                gainNode.gain.linearRampToValueAtTime(1, now + 0.1); // Attack
                gainNode.gain.setValueAtTime(1, now + 0.1);

                osc.connect(gainNode);
                gainNode.connect(filter);
                osc.start();

                activeNotes[note] = { osc, gainNode };
            } catch (error) {
                console.error('Error starting note:', error);
            }
        }

        // Function to stop a note
        function noteOff(note) {
            if (!activeNotes[note]) return;

            try {
                const { osc, gainNode } = activeNotes[note];
                const now = audioContext.currentTime;

                // Release phase
                gainNode.gain.cancelScheduledValues(now);
                gainNode.gain.setValueAtTime(gainNode.gain.value, now);
                gainNode.gain.linearRampToValueAtTime(0, now + 0.5);

                osc.stop(now + 0.5); // Stop oscillator after release phase
                setTimeout(() => {
                    osc.disconnect();
                    gainNode.disconnect();
                }, 600);

                delete activeNotes[note];
            } catch (error) {
                console.error('Error stopping note:', error);
            }
        }

        // Event listeners for keyboard keys
        const keys = document.querySelectorAll('.key');
        keys.forEach(key => {
            const note = key.getAttribute('data-note');

            // Mouse events
            key.addEventListener('mousedown', () => {
                noteOn(note);
            });

            key.addEventListener('mouseup', () => {
                noteOff(note);
            });

            // Touch events for mobile devices
            key.addEventListener('touchstart', (e) => {
                e.preventDefault();
                noteOn(note);
            });

            key.addEventListener('touchend', (e) => {
                e.preventDefault();
                noteOff(note);
            });

            // Keyboard navigation
            key.addEventListener('keydown', (e) => {
                if (e.key === 'Enter' || e.key === ' ') {
                    noteOn(note);
                }
            });

            key.addEventListener('keyup', (e) => {
                if (e.key === 'Enter' || e.key === ' ') {
                    noteOff(note);
                }
            });
        });

        // Real-time control updates
        document.getElementById('waveform').addEventListener('change', () => {
            // Waveform changes will affect new notes
        });

        document.getElementById('volume').addEventListener('input', (e) => {
            if (masterGain) {
                masterGain.gain.setValueAtTime(parseFloat(e.target.value), audioContext.currentTime);
            }
        });

        document.getElementById('cutoff').addEventListener('input', (e) => {
            if (filter) {
                filter.frequency.setValueAtTime(parseFloat(e.target.value), audioContext.currentTime);
            }
        });

        document.getElementById('resonance').addEventListener('input', (e) => {
            if (filter) {
                filter.Q.setValueAtTime(parseFloat(e.target.value), audioContext.currentTime);
            }
        });
    </script>
</body>
</html>

created 1 year ago

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