How Music Is Recorded: Sound Wave to File
Turn vibrations in air into numbers in a file
Turn vibrations in air into numbers in a file
Sound is a wave of air pressure. Click Play to hear a tone and see its wave. Higher frequency = higher pitch. Higher amplitude = louder. This is what a microphone "sees."
A computer cannot store a smooth wave. Instead it takes samples: measurements at regular intervals. The top shows the original smooth wave. The bottom shows what the computer captured. More samples = better quality.
Each step transforms the signal. Click any stage to see what the signal looks like at that point.
The same recording can be stored in different formats with different trade-offs.
Raw samples, no compression. Perfect quality. A 3-minute song at CD quality = 30 MB. Used in studios where quality matters most.
Removes frequencies humans barely hear. Same song = 3 MB (90% smaller). The most common format for streaming. Good enough for most listeners.
Compresses without removing data. Same song = 15 MB. Restores perfectly to the original. Used by audiophiles and archivists.
Spotify streams at 320 kbps (kilobits per second) on its highest setting. That is about 2.4 MB per minute. A vinyl record stores audio as physical grooves that a needle traces. Same music, completely different technology, separated by 100 years.
You've traced the journey from sound wave to digital file. A microphone captures vibrations, an ADC samples them thousands of times per second, and compression shrinks the result. Every song you stream went through this process.
Sound waves are pressure changes in air. A speaker pushes air forward and back. A microphone captures those pushes as electrical voltage changes.
A digital recorder measures the wave height thousands of times per second. CD quality: 44,100 samples per second. Each sample is a number.
16-bit audio has 65,536 possible values per sample. 24-bit has 16.7 million. More bits = more detail = larger files.
MP3 removes sounds humans cannot hear, reducing file size by 90%. Lossless formats (FLAC) compress without removing data. The trade-off: quality vs size.
Put your new knowledge into practice!