ABX Audiofile Test

Blind-test your ears against real MP3, AAC, Opus and Vorbis encodes, then map your hearing with an adaptive audiogram. One purchase, no subscription, all on-device.

Can you actually hear the difference between lossless audio and the streams you pay for? ABX Audiofile Test answers that question the way audio researchers do — with double-blind listening trials and real statistics.

LOSSLESS VS LOSSY Import a lossless track (WAV, AIFF, FLAC or Apple Lossless). The app encodes it with real codecs — MP3 (LAME), AAC and HE-AAC (Apple), Opus (Apple) and Ogg Vorbis (Xiph) — at a ladder of bitrates from 320 down to 32 kbps, every encode loudness-matched to the original so volume can never be the giveaway. Then you listen blind: A is the original, B is the encode, X is secretly one of the two. Your job is to say which.

Test one codec at a time, or select several and let every rung shuffle into one combined blind session. Service presets add single rungs at the bitrates popular streaming tiers publish — AAC 256, Vorbis 320/160/96, Opus 128 and 64 kbps — so you can test exactly the quality you stream every day against your own library.

HONEST RESULTS Your result is a transparency threshold per codec: the lowest bitrate you could not reliably tell from the original. Every verdict is statistical — per-rung and overall binomial p-values — and if your score pattern is consistent with guessing, the app tells you so rather than flattering you.

Share a result card as an image, or export a multi-page PDF report documenting exactly what was tested: source details, encoder versions and settings, per-rung score tables, and the exact command lines (lame, afconvert, oggenc) that reproduce each test file.

HEARING SWEEP An adaptive (Békésy) hearing test: 13 frequencies from 250 Hz to 20 kHz, each ear measured separately through your headphones. Hold a button while you hear the tone, release the moment it fades — the reversals bracket your threshold at each frequency. You get a full audiogram, your highest heard frequency, and a comparison against age-typical hearing. Levels are relative to your equipment, not calibrated — it shows what your ears and headphones resolve together, and it is not a medical assessment.

BUILT FOR REPEAT TESTING • Interactive practice walkthroughs teach the controls before your first real run • History keeps every result with its charts and reports • Re-run any past test exactly — same audio, same codecs, same number of trials • Recent tracks reload a saved source instantly, with no re-import • Drag & drop, AirDrop, and Files integration on iPhone, iPad and Mac

YOURS, PROPERLY One purchase covers iPhone, iPad and Mac. No subscription, no ads, no accounts, no analytics. Your audio never leaves your device.