Lossy vs Lossless: The One Distinction That Matters Most
Every digital audio format falls into one of two camps:
- Lossless formats reproduce the original recording bit-for-bit. FLAC, ALAC, and WAV are all lossless. FLAC and ALAC compress the file to save space (like a ZIP file) without discarding any audio data; WAV is uncompressed.
- Lossy formats permanently discard some audio information to shrink the file dramatically. MP3, AAC, and Ogg Vorbis are lossy. The discarded data is chosen by a psychoacoustic model that targets what the ear is least likely to notice.
"Lossless" means identical to the source — FLAC and ALAC sound the same as the original WAV; they simply take up less space. The only practical differences between lossless formats are file size and software compatibility, not sound quality.
Bit Rate: How Lossy Formats Are Graded
Lossy quality is set by bit rate — how many kilobits per second (kbps) are used to describe the audio. More bits means less is thrown away.
| Bit Rate | Verdict | Notes |
|---|---|---|
| 128 kbps MP3 | Audibly compromised | Smeared cymbals and thin highs; fine for podcasts, not music. |
| 256 kbps AAC | Very good | The standard for many download stores; transparent for most listeners. |
| 320 kbps MP3 | Excellent | Difficult to distinguish from lossless on most systems and material. |
Bit Depth and Sample Rate: What "Hi-Res" Means
Lossless and hi-res files are described by two numbers — bit depth and sample rate — covered in more depth in our DAC guide:
- Bit depth (16-bit, 24-bit) sets the dynamic range. CD quality is 16-bit; 24-bit adds headroom that is useful in production but offers no audible benefit at playback for finished music.
- Sample rate (44.1 kHz, 96 kHz, 192 kHz) sets the highest frequency that can be captured. CD's 44.1 kHz already covers the full range of human hearing.
"Hi-res" generally means anything above CD quality — typically 24-bit at 96 kHz or higher. CD quality itself (16-bit/44.1 kHz) is already lossless and already exceeds what most systems and rooms can reveal.
Assuming a hi-res file always sounds better than CD quality. The biggest factor in how a track sounds is the recording and the mastering, not the format. A great master at 16-bit/44.1 kHz will beat a mediocre master at 24-bit/192 kHz every time.
What Streaming Tiers Actually Deliver
Streaming services use these formats under the hood. The labels vary, but the substance comes down to lossy versus lossless versus hi-res:
- Standard / "High" tiers are usually lossy AAC or Ogg around 256–320 kbps — excellent for casual and on-the-go listening.
- "Lossless" / "CD quality" tiers deliver 16-bit/44.1 kHz FLAC or ALAC — the sensible target for a hi-fi system.
- "Hi-Res" tiers offer 24-bit files at higher sample rates — a genuine bonus on a resolving system, though the audible gain over CD-quality lossless is subtle to debatable.
To hear lossless or hi-res over a streaming service, the whole chain has to support it: the subscription tier, the app's output settings, and your DAC. A lossless subscription played through a phone's lossy Bluetooth codec is not delivering lossless to your ears.
A Note on MQA and Proprietary Formats
You may encounter proprietary "hi-res" delivery formats such as MQA, which use a folding technique to pack high-resolution audio into a smaller, lossy-compatible stream that a compatible decoder unfolds. These are convenient for streaming but remain debated, and the industry has been moving toward standard FLAC-based lossless and hi-res delivery. For a future-proof library, standard lossless formats are the safe choice.
Practical Recommendations
- For your own library: rip and store in FLAC (or ALAC if you live in the Apple ecosystem). It is lossless, compressed, and widely supported.
- For portable/casual use: 256 kbps AAC or 320 kbps MP3 is transparent and saves enormous space.
- For streaming on a hi-fi: choose a lossless (CD-quality) tier; treat hi-res as a nice-to-have, not a necessity.
- Don't chase numbers: prioritise good masters and a well-set-up system over ever-higher sample rates.
CD-quality lossless is the sweet spot for serious listening: provably identical to the source and supported everywhere. Lossy at 256–320 kbps is genuinely fine for most listening. Hi-res is a worthwhile bonus on a resolving system but rarely the difference people imagine — the master matters far more than the format.
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