Guide
Understanding Audio Quality Verdicts: How SoniqTools Analyzes Your Files
March 2026 · 10 min read
When you drop an audio file into SoniqTools, it doesn't just tell you the format and bitrate. It decodes every sample, examines the frequency spectrum, measures dynamics, checks for clipping, and delivers a verdict that tells you what the file actually is — not just what it claims to be.
This article explains the analysis methodology behind SoniqTools and walks through every verdict you might see, so you know exactly what your results mean.
How SoniqTools analyzes your audio
Every analysis runs entirely in your browser using the Web Audio API. No files are uploaded, and nothing leaves your device. Here are the six dimensions SoniqTools examines:
Spectral Analysis
An FFT-based frequency spectrum reveals where audio content actually exists — and where it abruptly stops. This is the primary tool for detecting fakes.
Frequency Cutoff
SoniqTools detects the highest frequency with meaningful content and compares it to the Nyquist frequency. A file that stops well short of its theoretical maximum is suspicious.
Dynamic Range
The crest factor measures the gap between average loudness and peaks. High values (14+ dB) indicate natural dynamics. Low values suggest heavy compression from the "loudness war."
Clipping Detection
When audio exceeds 0 dBFS, the waveform is clipped flat, introducing harsh distortion. SoniqTools scans every sample to measure how much clipping has occurred.
Stereo Correlation
Measures how similar the left and right channels are. Values near 1.0 mean near-mono; 0.3–0.8 is typical stereo. Negative values indicate phase issues.
Format Detection
Identifies the codec (FLAC, MP3, AAC, etc.), container format, sample rate, bit depth, and bitrate. Determines whether the format is lossless or lossy.
After gathering all this data, SoniqTools cross-references the results to produce a single verdict. A file might claim to be 96 kHz hi-res FLAC, but if the spectrum cuts off at 16 kHz, SoniqTools will flag it as upsampled.
The verdict system
Verdicts fall into two categories:
- Quality verdicts describe what the file genuinely is — from the best possible quality down to the lowest bitrate. These follow a color gradient from green (best) to dark rose (worst).
- Suspicious verdicts flag files where the container format doesn't match the actual content. These are always shown in orange or yellow to indicate something isn't what it seems.
Key point: A suspicious verdict doesn't necessarily mean someone tried to deceive you. Upsampling can happen accidentally during format conversion, and some streaming services transcode files without disclosing it. The verdict simply tells you that the audio quality inside doesn't match the container's promise.
Quality verdicts
These six verdicts represent the actual quality tier of your audio file, ranked from best to worst.
The gold standard. This file has a sample rate above 44.1 kHz (typically 88.2, 96, or 192 kHz) and/or bit depth greater than 16-bit, and spectral content that actually extends beyond CD-quality range. This confirms the high-resolution format is genuine, not just an upsampled CD.
Typical files: Studio masters, hi-res downloads from Qobuz or HDtracks
A standard resolution file at 44.1 or 48 kHz with 16-bit depth. This is CD quality — the benchmark for high-fidelity audio. If the file is lossless (FLAC, WAV, ALAC), every sample is preserved exactly as the artist intended. This is more than sufficient for virtually all listening scenarios.
Typical files: CD rips, standard FLAC/WAV downloads, lossless streaming
A lossy file (MP3, AAC, OGG, Opus) encoded at 256 kbps or above. At this bitrate, lossy compression is remarkably efficient — multiple blind tests have shown that most listeners cannot distinguish high-bitrate lossy from lossless originals. For everyday listening, this is excellent quality.
Typical files: 320 kbps MP3, 256 kbps AAC (iTunes Plus), high-quality streaming
A lossy file encoded between 192 and 255 kbps. This is a balanced compromise between file size and quality. Some trained listeners may notice subtle differences compared to lossless on revealing tracks, but for most music and most listening environments, this quality level is perfectly enjoyable.
Typical files: 192 kbps MP3, standard quality streaming, some podcast platforms
A lossy file encoded between 96 and 191 kbps. Quality is comparable to FM radio. High frequencies are noticeably reduced, and compression artifacts may become audible on detailed passages. Acceptable for casual background listening, but not ideal for critical evaluation or high-quality playback systems.
Typical files: 128 kbps MP3, mobile streaming on data-saving mode, standard podcasts
A lossy file encoded below 96 kbps. Audio quality is noticeably degraded — similar to AM radio. High frequencies are heavily cut, and compression artifacts are clearly audible. This bitrate is typically used for voice-only content like phone calls or spoken-word recordings where music quality is not a priority.
Typical files: 64 kbps MP3, voice memos, low-quality podcast feeds, phone audio
Suspicious verdicts
These three verdicts indicate a mismatch between what the file claims to be and what it actually contains. The audio may have been upsampled or transcoded from a lower-quality source.
The file has a hi-res sample rate (e.g. 96 kHz), but spectral content cuts off far below the Nyquist frequency. This strongly suggests the source material was lower resolution — likely CD quality or even lossy — and was upsampled to a higher sample rate. The extra samples contain no real audio information.
What to do: You're storing a much larger file than necessary. The actual audio quality matches the lower source, not the claimed hi-res format.
The file claims hi-res specifications, but no meaningful spectral content exists beyond the CD-quality range (~22 kHz). The evidence is suggestive but not conclusive — some recordings, especially older masters or acoustic genres, naturally have limited high-frequency content. Worth investigating further, but not a definitive flag.
What to do: Check the source. If the file came from a reputable store (Qobuz, HDtracks), it may be a genuine older master. If the source is unknown, treat with skepticism.
The file is in a lossless container (FLAC, WAV, ALAC), but its spectral content cuts off in a way characteristic of a lossy source — typically around 16–19 kHz for MP3 or AAC. Someone took a lossy file and re-encoded it as lossless. You get the file size of lossless with the quality of lossy — the worst of both worlds.
What to do: The original lossy source would sound identical in a fraction of the file size. If you paid for lossless, you didn't get what you paid for.
A note on context: No automated analysis is perfect. Some legitimately mastered recordings have unusual spectral characteristics. SoniqTools gives you the data — use it alongside your knowledge of the source and your own ears.
Why knowing your audio quality matters
You might wonder: does any of this really matter? If the music sounds fine, who cares what the spectrogram says? Here's why it's worth knowing.
You should get what you pay for
If you're paying a premium for lossless or hi-res downloads, you deserve to know the files are genuine. A transcoded FLAC gives you the storage cost of lossless with the audio quality of a 128 kbps MP3. That's not what you paid for. SoniqTools lets you verify purchases instantly.
Storage efficiency
A fake hi-res file can be 10 times larger than the lossy original it was transcoded from, with zero quality benefit. If you're managing a large music library, identifying and replacing transcoded files can reclaim significant storage space — or let you know which files are worth keeping in lossless and which are fine as high-quality lossy.
Playback equipment
If you've invested in quality headphones, a DAC, or speakers, your equipment faithfully reproduces whatever it receives — including compression artifacts from a low-bitrate source wrapped in a lossless container. Knowing your file quality ensures your signal chain is actually delivering the experience it's capable of.
Professional use
DJs playing through club sound systems, producers sampling tracks, and audio engineers working on projects all need to know the true quality of their source material. A transcoded file that sounds passable on laptop speakers can fall apart on a high-powered PA system. The missing high-frequency content and compression artifacts become impossible to ignore at volume.
Archiving for the future
If you're building a long-term music archive, knowing exactly what quality you have today matters for decisions you'll make tomorrow. A verified lossless file can always be converted to any format later. A lossy file disguised as lossless gives you a false sense of security — the quality is already permanently reduced, and no future conversion can bring it back.
Analyze your audio files now
Drop any audio file into SoniqTools for an instant quality verdict. Free, browser-based, and your files never leave your device.
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