The macOS music player built for collectors who live between two worlds — physical records and digital files — and refuse to compromise on either.
$39.99 · One-time purchase · No subscription · Apple Silicon only
You know the feeling. You're playing a first pressing — or what you think is a first pressing. You bought a hi-res download — or what the store claimed was hi-res. You want to know the story behind a recording — but that means fifteen browser tabs and an hour you don't have.
Every other app chose a side. Streamers forgot local files. Analyzers forgot playback. Players forgot the collector. No one built the app for the person who cares about all of it.
Not a feature list. Five answers to five problems that have bothered you for years.
Not a toolbar. A protocol. Guardian's Path is the structured analysis journey for listeners who want to know everything there is to know about a recording before they commit to it.
Good tools exist for parts of the problem. Achos is the only one that holds the whole thing.
| Capability | Achos | Format Checker | Spectrum Viewer | Academic Analyser |
|---|---|---|---|---|
| Audiophile playback (BitPerfect) | ✓ | — | — | — |
| DSD native support | ✓ | — | — | — |
| Spectral / format analysis | ✓ | ✓ | ◐ | ✓ |
| AI forensic verdict | ✓ | — | — | — |
| ITU-R BS.1770 / EBU R128 | ✓ | — | — | ◐ |
| Discogs collection sync | ✓ | — | — | — |
| Pressing Intelligence | ✓ | — | — | — |
| AI musical narrative (GRaiL) | ✓ | — | — | — |
| One-time purchase | ✓ | ✓ | ✓ | ✓ |
◐ Partial support · — Not available · Data reflects publicly available feature sets as of 2026.
Áchos
ἄχος · Ancient Greek
"The deep ache of one who refuses compromised sound. The grief of the collector who knows something is wrong but has no tool to prove it."
Collectors know the ache. You hold a record you love and wonder — is this the real first pressing, or a later reissue? You play a hi-res file you paid good money for and something feels off. You want to know the story of what you're hearing but you'd need an hour you don't have. The tools existed for parts of the problem. No one had built the whole thing.
Achos started as that frustration, turned into a question, turned into a project. The name comes from Homer — ἄχος, the specific ache of a person who knows what should exist but doesn't yet. Not sadness. Not anger. The particular tension of someone who refuses to accept less than what the music deserves.
The result is an app that lives where collectors actually live — at the intersection of physical and digital, of instinct and evidence, of listening and knowing. Where your vinyl and your files finally share a shelf.
Achos was built by one person. Every architectural decision, every design principle, every line of code — produced over 44 consecutive days through a documented Human-AI co-creative process under the academic COFI framework. Not AI-assisted. Co-created. The evidence is in the download below: 49 sessions, 63 co-authored git commits, 4 case studies, and a methodology that Rezwana & Maher (ACM, 2023) would recognize immediately.
Two documents for those who want to go deeper — the complete technical reference and the academic evidence of how Achos was built.
The complete reference for every feature, measurement standard, and methodology in Achos. Covers the dual-FFT architecture, ITU-R BS.1770 True Peak, EBU R128 loudness, DSD noise shaping analysis, brickwall detection, and the full fingerprint field reference. Written for collectors and audio engineers alike.
The academic evidence corpus for Achos's 44-day COFI-conformant development. Documents 49 sessions, 63 co-authored git commits, 31 structured prompt files, and 4 detailed case studies — including the DSD bug sprint, the three-queue architecture negotiation, and the epistemic verdict taxonomy redesign. Co-authored by Martín Gallardo and Claude Sonnet 4.6.
Finally, an app that speaks collector. BitPerfect playback, AI file forensics, Discogs integration, and GRaiL — the complete tool for the Guardian of Sound.