What is Digital Audio?
Digital audio is sound stored as numbers - the foundation of all music, podcasts, and voice recordings on computers
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Digital Audio: Simple Definition
Digital audio is sound that has been converted into numerical data that computers can store and process. When you record audio digitally, the sound waves are sampled thousands of times per second and each sample is stored as a number.
CD-quality audio samples sound 44,100 times per second (44.1kHz) and stores each sample as a 16-bit number. This creates perfectly accurate sound reproduction that can be played back identically on any device.
Sampling and Quantization
Converting sound to digital form involves two steps: sampling measures the waveform at regular intervals, and quantization rounds each measurement to a fixed number of bits.[3] The sampling rate sets the highest reproducible frequency—by the Nyquist principle it must be at least twice that frequency—which is why 44.1 kHz comfortably covers the roughly 20 kHz limit of human hearing.[3]
Uncompressed, Lossless and Lossy
Audio can be stored uncompressed as raw PCM (as in WAV), losslessly compressed (FLAC) to shrink size with no quality change, or lossily compressed (MP3, AAC, Opus) to shrink it much further by discarding inaudible detail.[4] Modern codecs such as Opus adapt well across both speech and music at low bitrates.[4]
Channels and Containers
An audio stream may carry one channel (mono), two (stereo) or more for surround sound, multiplying the data accordingly.[1] The encoded stream is then placed in a container, and tools such as FFmpeg can transcode between codecs or remux between containers.[2]
How Digital Audio Works
An analog-to-digital converter (ADC) measures the amplitude (loudness) of a sound wave at regular intervals and converts each measurement to a digital number. The more samples taken per second (sample rate) and the larger each number (bit depth), the more accurate the representation.
When you play audio, a digital-to-analog converter (DAC) reads the numbers and reconstructs the original sound wave, which is then amplified and sent to speakers or headphones.
Examples of Digital Audio
CD quality audio
44,100 samples per second, 16-bit depth. The standard for music distribution since 1982.
Hi-Res audio
96kHz or 192kHz sample rate, 24-bit depth. Used by audiophiles and professional recording studios.
Phone calls
8kHz sample rate, 8-bit or G.711 compression. Minimum quality for understandable speech.
Streaming audio
AAC at 256kbps (Apple Music) or OGG Vorbis at 320kbps (Spotify). Lossy compression of CD-quality source.
Work With Your Files
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Try Audio Converter FreeFrequently Asked Questions
What is sample rate?
Sample rate is how many times per second audio is measured. CD uses 44.1kHz (44,100 samples/second). Higher rates capture more detail.
What is bit depth?
Bit depth determines the dynamic range of audio. 16-bit (CD) gives 96dB range. 24-bit (Hi-Res) gives 144dB range.
Is 24-bit audio better than 16-bit?
For recording and editing, yes. For final listening, the difference is essentially inaudible on consumer audio equipment.
What is the best audio format?
FLAC for lossless archiving. AAC or OGG for compressed listening. WAV for professional production.
What does “lossless” mean for audio?
Lossless audio (FLAC, ALAC, WAV) stores all the original data perfectly. Lossy audio (MP3, AAC) discards some data to achieve smaller file sizes.