Digital audio is a long list of samples. Lossy formats such as MP3, AAC and Opus throw some of that information away to make files smaller, using a model of what human hearing is likely to miss. Lossless formats such as FLAC, ALAC and WAV keep all of it.
Lossless does not automatically mean better sounding to everyone: a high-bitrate AAC file is very hard to tell apart in practice. But a lossless file is an exact copy of the master, which matters for archiving, editing and critical listening.
CD quality vs hi-res
| Tier | Format | Data rate |
|---|---|---|
| Lossy (high) | AAC 256 kbps / MP3 320 kbps | 256–320 kbps |
| Lossless CD quality | 16-bit / 44.1 kHz | ≈ 700–1000 kbps as FLAC |
| Hi-res lossless | 24-bit / 48–192 kHz | ≈ 1.5–5 Mbps as FLAC |
What you need to actually hear lossless
- A lossless source: a lossless streaming tier or genuine FLAC or ALAC files. A FLAC made from an MP3 is not lossless; check it with a spectrum analyzer.
- A wired connection or a DAC. Standard Bluetooth re-compresses audio with a lossy codec, so AirPods and most wireless headphones cannot play true lossless.
- For hi-res above 48 kHz, an external DAC that supports it, since phones and laptops often resample internally.
Lossless vs Dolby Atmos
Dolby Atmos (spatial audio) is about where sounds are placed around you, not about data compression. Atmos music on streaming services is delivered in a lossy format, and it is a different mix of the song rather than a higher quality version of the stereo mix.
Frequently asked questions
Can you hear the difference between lossless and AAC?
Most people cannot reliably tell 256 kbps AAC from lossless in blind tests. Differences, when audible, show up on good wired gear and in complex passages.
Do AirPods play lossless?
Not over Bluetooth. The audio is re-encoded with a lossy codec before transmission, so the lossless benefit is lost.
Is hi-res worth it?
24-bit / 96 kHz files capture more than human hearing needs for playback. They are valuable for production and archiving; for listening, CD-quality lossless is already transparent.
Related tools
Quality Analyzer
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FLAC vs MP3: Can You Hear the Difference?
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How to Tell if a FLAC File Is Really Lossless
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Audio Bitrate Explained: Which Bitrate Should You Use?
Which bitrate to pick for music, voice and video.