Find out before the gig.
Half your "lossless" tracks
are actually MP3s.
Fake lossless detector · WAV · AIFF · FLAC · ALAC · MP3 · AAC · macOS
Spectro tells you exactly which WAV, AIFF, and FLAC files in your library are actually compressed MP3s in disguise. Drop your Beatport or Bandcamp downloads and get an instant verdict - before you play them on a professional system.
Free for your first 100 tracks · No account required · No internet needed
< 1s
Per file verdict
100%
Offline & Private
One-time
No subscription
The problem
A .flac extension means nothing.
The spectrogram never lies.
Online stores, promo channels and Bandcamp uploads are full of MP3s upscaled and renamed to FLAC, WAV or AIFF. The file size goes up. The audio inside doesn't. Spectro reads the actual waveform with a full FFT, like a luthier tapping wood.
track-04-master.flac
320 kbps MP3 transcoded to FLAC. The container is lossless. The audio inside still has the MP3's missing top octave. You paid for nothing.
turbo-rosso-original.wav
Energy reaches the Nyquist ceiling. Air, transients and shimmer survive intact. This is what you bought.
What you get for $29
Built for the way real DJ and
audiophile libraries look in 2026.
Spectro isn't a one-trick spectrogram viewer. It's a verdict engine, a batch scanner and a Finder-native quality control tool, tuned for libraries with tens of thousands of files.
Verdict per file
Every file gets a single answer: LOSSLESS, MEDIUM, or FAKE, with confidence %, estimated cutoff, and a one-line diagnosis. No squinting at color blobs.
VERDICT ENGINE · V1.4
Batch the whole crate
Drop 1 file or 20,000. Import directly from Rekordbox XML or any M3U/M3U8 playlist. Spectro processes up to 100 files in parallel and groups results by verdict. Filter the FAKEs, copy paths, reveal in Finder.
~1,000 FILES / MIN · M-SERIES
Finder color tags, automatic
Spectro writes Finder tags directly to your files. Open any folder and the bad ones are already marked red. No app required to keep them flagged.
NATIVE MACOS FINDER
Runs 100% on your Mac
Audio never leaves the device. No cloud upload, no telemetry on your library, no account required to install. Sandboxed and notarized by Apple.
OFFLINE · NO ACCOUNT
One purchase, two Macs
Your studio iMac and your gig-bag MacBook on the same license. Free v1 updates, lifetime. No subscription, no per-track fee, no re-purchase next year.
LICENSE · 2 SEATS
Watch folder + Mac-native
Point Spectro at any folder. New tracks dropped in get analyzed automatically, with optional notifications when a batch finishes. Universal binary for Apple Silicon and Intel. macOS 13+. Sparkle auto-updates. Notarized and sandboxed, built for Mac, not ported from Windows.
WATCH FOLDER · SPARKLE
Works with your setup
Fits into your existing workflow.
Import from Rekordbox XML or any M3U/M3U8 playlist, compatible with Traktor and VirtualDJ. Serato support coming soon.
SoonHow it works
Three steps. No setup.
No library re-import.
Spectro doesn't need to know about your music management app. Drop files, get verdicts, decide what to do with them.
Step 01
Drop files or folders
FLAC, WAV, AIFF, ALAC, MP3, AAC. Drag in a track, an album, or your whole ~/Music folder. No import. No moving anything.
Drop files or folders
FLAC · WAV · AIFF · ALAC · MP3 · AAC
Step 02
Get a verdict per file
Spectro analyzes each file's actual spectral content, not the metadata or the extension. Results stream in live as they finish.
Step 03
Act on what you find
Filter by verdict, move fake files directly to Trash, or click any track to inspect its full spectrogram before deciding whether to replace it.
macOS Finder integration
Fake lossless files, tagged in red.
Right in Finder.
Spectro writes color tags directly to your files in macOS Finder. Open your DJ Pool folder and every track is already marked. No app to keep open, no renaming, no extra steps.
Why you can trust the verdict
Detection backed by peer-reviewed
research. Built native. Run offline.
99% accuracy on transcoding detection,
across 2,512 songs.
Spectro's spectral analysis is built on the methodology of D'Alessandro & Shi's peer-reviewed paper on MP3 bit-rate quality detection. The only known ambiguous case (256 kbps CBR vs. high-quality VBR) gets 92.4% accuracy, which Spectro flags explicitly as MEDIUM in the diagnosis panel.
Your library never leaves your Mac.
Drop a folder, get verdicts. Spectro runs entirely on your machine: no internet required, no account to create, no files ever uploaded. Pull the network cable and it still works exactly the same.
- Works fully offline, no internet needed
- No account, no sign-up, no tracking
- Apple Silicon (M1–M4) + Intel
- Secure checkout via Lemon Squeezy; we never see your card
From the community
What users found in their libraries
Pricing
$29 launch. $39 after.
Not per month, not per file, not per Mac.
If Spectro finds one fake file in a release you were about to play out, it has paid for itself many times over. If it doesn't, refund it. No email gymnastics.
Spectro · Personal
Everything below. Lifetime v1 updates.
$29
$39
once · USD
save $10 with code LAUNCH29
competitors charge $9.99/mo ($119/yr)
Unlimited file scans
No quotas, no per-file fees
Activate on 2 Macs
Studio + gig-bag, same license
Free v1 updates
All updates included, forever
Offline · private
No cloud, no account, no upload
100-track free trial included
No card required to start
30-day money-back guarantee
One email. Done.
Launch price. After this period it returns to $39.
Or start with the free 100-track trial
macOS 13 Ventura or later · Universal binary
Launch price in context
One "FLAC" you paid for that turned out to be MP3
Average Beatport / Bandcamp / Traxsource price per track
$2.49
A hi-res album that turned out to be upscaled MP3
Average price per album (Bandcamp, HDtracks, Qobuz store)
$15–25
A "lossless" streaming subscription
Qobuz, Tidal, Apple Music Lossless, annual per service
$119/yr
A typical Spectro user's first scan
Aegis7 on r/macapps · 653-track library
10 fake · 57 medium
Spectro
One-time, two Macs, lifetime v1 updates
$29 $39
Break-even at
16 fakes caught
Use Cases
Start with your workflow
Choose the guide that matches your setup. Each page is focused on one intent so you can move from search to trial quickly.
Fake Lossless Checker for Mac
Detect MP3 transcodes disguised as WAV, AIFF, or FLAC.
Open guide
Spek Alternative for macOS
Modern spectrum workflow with batch verdicts and Finder tags.
Open guide
Audio Quality Checker for DJs
Pre-gig quality control workflow for large DJ libraries.
Open guide
Rekordbox Audio Checker
Audit tracks before USB export in your Rekordbox prep flow.
Open guide
Find out what's actually
in your library tonight.
Drop your most suspicious folder into Spectro and have your answer
before the kettle boils.