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Understanding audio resolution: from 320 kbps to CD, 24-bit hi-res and DSD — and what the HRQ score measures

Digital resolution: the technical data first, then the visual demonstration.

Technical data

Resolution HRQ Spotify Apple Music TIDAL Deezer Amazon Music Qobuz DSD streaming
256–320 kbpslossy (OGG, AAC, MP3) 10 “Very high”OGG 320 “High Quality”AAC 256 “Low”AAC 320 “High Quality”MP3 320 “SD” “MP3”discovery listening —
16-bit / 44.1 kHzlossless · CD quality · ≈ 1.4 Mbit/s 30 “Lossless”FLAC, up to 24/44.1 “Lossless”ALAC, up to 24/48 “High”FLAC “HiFi”FLAC — Deezer's maximum “HD”FLAC “CD”FLAC —
24-bit / 96 kHzhi-res · ≈ 4.6 Mbit/s 49 — “Hi-Res Lossless” “Max” — “Ultra HD” “Hi-Res” —
24-bit / 192 kHzstudio master · ≈ 9.2 Mbit/s 89 — “Hi-Res Lossless”up to 24/192 “Max”up to 24/192 — “Ultra HD”up to 24/192 “Hi-Res 192” —
DSD64 · 2.8 MHz1-bit (SACD) 58 ————— DownloadQobuz Store: DSD64 to DSD512, DXD no servicePrimeSeat (Japan) closed in January 2023
DSD128 · 5.6 MHz 98 ————— — —
DSD256 · 11.2 MHz off the scale ————— — —

The service and plan names cited are trademarks of their respective owners, mentioned for strictly informational and comparative purposes. Hi Res Quest is independent: it belongs to none of these platforms, is endorsed by none of them, and none of them pays it for its ranking. Some purchase links (Qobuz Store) are affiliate links, labeled “affiliate link”: they change neither the order nor the price.

The HRQ score, in plain terms

Every platform has its own vocabulary — “Lossless”, “HiFi”, “Master”, “Ultra HD”, “Hi-Res”… from one service to the next, nothing is comparable anymore. The HRQ score brings everything down to a single number.

What it measures: the amount of information actually transmitted every second — the data rate. An audio file is a bit depth × a sample rate × two channels (stereo). The higher these values, the higher the data rate, the higher the score. The rule: an exponential weighting of the data rate — on average, doubling the data rate multiplies the score by ×1.55 (20.64). The scale is calibrated on real listening reference points, from lossy (10) to DSD128 (98).

The scale: lossy listening ≈ 10 · CD 16/44.1 = 30 · 24/96 = 49 · 24/192 = 89 · DSD128 = 98. Beyond that (DSD256), you are off the scale: the gain in data rate no longer translates into a gain in listening. The curve below shows it point by point.

Two essential safeguards:

  1. The score says what is transmitted, not what you hear. Your connection can throttle everything: over Bluetooth, a 24/192 source drops back to around 10 (the sound is recompressed). The table “What your connection really lets through”, further down, details each case.
  2. The score rates the container, not the authenticity of the master. A “24/192” file resampled from a CD shows a high score without containing any more music. That is why the score is always read together with the authenticity badge: HRQ prefers an authentic CD (30, real) to a fake 24/192 (89, inflated).

The HRQ gradation (exponential weighting of the data rate: doubling the data rate ≈ ×1.55 on the score)

02550 75100 HRQ score 103049588998 0.32 Mbit/s1.41 Mbit/s4.61 Mbit/s5.64 Mbit/s9.22 Mbit/s11.29 Mbit/s LossyLosslessHi-ResDSD64Hi-ResDSD128 320kCD 16/44.124/96SACD24/1925.6 MHz

The score says what is transmitted; your equipment says what you hear. The HRQ above rates the amount of information in the file, with an exponential weighting: on average, doubling the data rate multiplies the score by ×1.55. But between the file and your ear, every link in the chain imposes its own ceiling. Over Bluetooth, the sound is recompressed no matter what: even from a 24/192 source, you stay around HRQ 10 — paying for a hi-res subscription to listen on AirPods has no effect. AirPlay / Wi-Fi goes up to CD quality. And only a wired external DAC unlocks real hi-res. In other words: the connection is often the real ceiling, well before the platform.

What your connection really lets through

ConnectionMax data rateQuality deliveredReachable HRQThe limit
Bluetoothwireless AirPods, BT earphones & speakers ~0.3 Mbit/s lossy ~10 Recompressed every time (SBC, AAC, aptX HD, LDAC). The only exception, a rare one: aptX Lossless, CD quality 16/44.1 at best, with compatible hardware on both ends.
AirPlay 2 / Spotify Connectfrom an iPhone or the Spotify app 0.26 – 1.41 Mbit/s AAC 256 to CD quality ~10 – 30 Apple Music via AirPlay 2 from an iPhone = AAC 256 kbps; other apps go through at 16/44.1 (CD); Spotify Connect = up to 24/44.1. No hi-res above 48 kHz.
Qobuz Connect / TIDAL Connect / Chromecast / RoonWi-Fi, network player up to 9.2 Mbit/s lossless — up to 24/192 up to 89 The track's full resolution, depending on the playback device (streamer, connected amplifier, network DAC).
Wired — the phone's DACLightning adapter / headphone jack ~2.3 Mbit/s lossless up to 24/48 ~36 Good, but the built-in DAC tops out at 24/48.
Wired + external DAC+ wired headphones 9.2 Mbit/s and up real hi-res 24/96 → 24/192, DSD 49 → 98 The only path to hearing everything.

Resolution, visually

1.0 Mbit/s CD · 16-bit / 44.1 kHz lossless — actual 1.4 Mbit/s raw · ≈ 1 delivered (FLAC)
MP3 CD 24/96 DSD64 24/192 DSD128 DXD DSD256

To the left of CD, compression removes data; from CD onward, everything is lossless. SACD's DSD exists as 64, 128, 256 — up to DSD1024 in the studio; its usable bandwidth is about 50-60 kHz and its exact equivalences with PCM are debated. At these levels, what sets two versions apart is the master — exactly what the audit sets apart, track by track. Full sharpness only arrives at DSD256: each step improves the image, less and less strongly. This image illustrates the data rate, not what the ear perceives. The image goes from black and white to color up to the CD step: lossy compression removes information, lossless restores everything. Today's reference: a CD stream delivered as FLAC weighs ≈ 1 Mbit/s (1.411 raw); premium lossy streams ≈ 0.32-0.45 Mbit/s. AI-generated footage (KlingAI, 2026) — fictional characters.

Digital resolution, explained simply

Written to be understood without a technical background. The stage above serves as a visual reference throughout.

1. Digital sound is made of snapshots

To digitize a sound, you photograph the sound wave tens of thousands of times per second. That is the sample rate: 44,100 times per second for a CD (44.1 kHz), 96,000 or 192,000 for hi-res. At 44.1 kHz, everything audible (up to 22.05 kHz) is captured exactly (sampling theorem); 96 or 192 kHz extend the recorded band beyond hearing — useful in the studio, with no “smoother” motion when listening. Our trio stage illustrates the data rate, not perception.

Further reading: Qobuz — understanding audio quality (official guide) · TIDAL — Sound Quality (official) · Apple Music — lossless audio (official support) · Xiph.org — video demonstration (French subtitles available) · Wikipedia — sampling theorem · What Hi-Fi — the hi-res guide

2. Bit depth is the nuances

Each snapshot records the level on a scale. In 16-bit (CD), that scale has 65,536 levels. In 24-bit, 16.7 million. In practice: a lower noise floor. Dithered 16-bit already offers about 96 dB of dynamic range, more than any listening room; 24-bit brings the studio's safety margin (mixing, processing), not extra audible “nuances” in your home.

Further reading: Qobuz — understanding audio quality (official guide) · TIDAL — Sound Quality (official) · Apple Music — lossless audio (official support) · Xiph.org — “bit-depth” and “dither” chapters · Wikipedia — quantization · HydrogenAudio — dither

3. MP3 throws details away

A 320 kbps file (MP3, OGG) compresses by removing what the ear is supposed not to notice. It is efficient, but irreversible: the discarded details never come back. That is the far-left position of the slider — the image stays recognizable, but blurry up close.

Further reading: Qobuz — understanding audio quality (official guide) · Spotify — audio quality (official support) · Deezer — audio quality (official support) · Fraunhofer — the history of MP3 by its inventors · NPR — “The MP3: A History” · Wikipedia — MP3

4. Lossless restores the original

Lossless (FLAC, ALAC) compresses without losing anything: on playback, you get back exactly the original file, bit for bit. CD quality (16-bit/44.1 kHz) is the foundation: already excellent, it is the sharp image halfway along the slider.

Further reading: Qobuz — understanding audio quality (official guide) · TIDAL — Sound Quality (official) · Apple Music — lossless audio (official support) · Spotify — audio quality (official support) · Deezer — audio quality (official support) · Xiph.org — the official FLAC site · Wikipedia — FLAC · HydrogenAudio — FLAC

5. Hi-res goes beyond CD

Hi-res (24-bit/96 kHz, then 24-bit/192 kHz) captures more snapshots with more nuances. The HRQ score measures the data rate, not the listening: the 320 kbps → CD gap is certain (data has been removed) but rarely distinguished in blind tests; the 96 → 192 kHz gap practically never is (blind studies, Reiss 2016). So our scale rates the information transmitted, not a promise of what you will hear.

Further reading: Qobuz — understanding audio quality (official guide) · TIDAL — Sound Quality (official) · Apple Music — lossless audio (official support) · Reiss 2016 (Queen Mary Univ.) — the meta-analysis, PDF · What Hi-Fi — the hi-res guide · Meyer & Moran 2007 — the blind study

6. SACD and DSD, a different philosophy

SACD uses DSD: no longer detailed snapshots, but an ultra-fast stream of 1-bit pulses — 2.8224 MHz for SACD's DSD64, doubling at each step: DSD128 (5.6448 MHz), DSD256 (11.2896 MHz), up to DSD512 and DSD1024 in the studio. Its usable bandwidth is about 50 to 60 kHz and its conversions to PCM are done in multiples of 88.2 kHz; the exact perceptual equivalences are debated. One indisputable reference point: the raw data rate — DSD64 (5.6 Mbit/s) sits between 24/96 (4.6) and 24/192 (9.2), and DSD128 (11.3) just above 24/192. That is the continuous scale of the slider above. At an equal data rate, however, a 1-bit stream carries less useful information than PCM (part of the data rate is noise-shaping noise): the DSD score is a data-rate reference point, not an equivalence.

Further reading: Qobuz — understanding audio quality (official guide) · TIDAL — Sound Quality (official) · Apple Music — lossless audio (official support) · Wikipedia — Direct Stream Digital · NativeDSD — the DSD specialist store · The Absolute Sound — the “all-DSD” approach

7. What matters most: the master

The same track often exists in several masters (the original, the 1995 remaster, the anniversary edition…). An excellent master in CD quality sounds better than a mediocre master in 24-bit/192 kHz. The format is the container; the master is the content. That is precisely what the Hi Res Quest audit sets apart, track by track: which edition is the best version, across all platforms — by cross-referencing real quality and popularity per edition.

Further reading: Qobuz — understanding audio quality (official guide) · Spotify — volume normalization (official support) · Deezer — volume normalization (official support) · Wikipedia — the loudness war · Dynamic Range DB — the dynamic range of 190,000 albums measured · Stereophile — “Winning the Loudness Wars”

8. Upsampling: the same tool, two opposite uses

Oversampling (upsampling) means recalculating intermediate points of a signal that is already fully defined by its original samples: the operation adds no information — zooming in on a photo does not invent details. Hi-fi upsamplers (Chord, dCS…) use it on playback, in your home: they help the converter better reconstruct what the file already contains. A legitimate technique, born with the CD — the first Philips player (CD100, 1983) already oversampled ×4 — and the very high end is actually divided on it: some manufacturers (Audio Note, Kondo) refuse any oversampling, at the same prices. “Fake hi-res”, on the other hand, applies the same operation before the sale: a CD master upsampled and then relabeled “24/192” — same content, higher price, sharp cutoff at 22.05 kHz on the spectrogram. Hi Res Quest rates the file and its authenticity; your upsampler, your DAC and your speakers work downstream, outside the scope of the rating. Then listen for yourself: choose the version that works best with your system and your ears. To check a specific track without the file: real hi-res or upsampled CD, how to tell on a streaming service.

Further reading: Qobuz — understanding audio quality (official guide) · Wikipedia — oversampling · Hi-Fi News — the Philips CD100 (1983) · GoldenSound — Chord M-Scaler measurements · 47 Labs — the opposite school, zero oversampling

And where does Spotify fit in?

Spotify tops out at 24-bit/44.1 kHz (CD quality). Lossless has been included in the Premium subscription since September 2025 (supported markets), on nearly the entire catalog — but never real hi-res above 44.1 kHz (neither 96 nor 192 kHz), unlike Qobuz, TIDAL, Apple Music or Amazon Music, which reach 24-bit/192 kHz. From one track to the next, it is therefore not the resolution that varies, but the availability of lossless (and you have to turn it on, wired or via Connect — Bluetooth recompresses). To go beyond CD, you need another platform: that is what sync is for.