# Lossless Audio Authenticity Checker Locally screen FLAC and WAV for persistent spectral cutoffs. Inspect evidence, not a promise of authenticity. > Canonical page: https://elysiatools.com/en/tools/lossless-audio-authenticity-checker - **Category:** Media - **Keywords:** Lossless Audio Authenticity Checker, Average power spectrum, Sampled spectrogram ## Overview ### Local spectral screening Open a FLAC or PCM/float WAV in the interactive panel. Audio is decoded in a browser worker without resampling or uploading. Download a spectrum PNG and a JSON evidence report. ### Honest conclusions “Suspicious” means a persistent sharp spectral edge, not proven fraud. Genuine low-pass/old masters can trigger it. “No obvious traces” does not prove a lossless source: high-bitrate encodes, gradual rolloffs and unsampled edits can be missed. Silence, tones, short clips and low sample rates may be inconclusive. This is not a codec, bitrate, MDCT fingerprint, FLAC MD5 or effective-bit-depth detector. ### Limits and API 100 MiB, 60 minutes, 8–192 kHz, mono/stereo. Native FLAC with known length, metadata ≤2 MiB and blocks ≤16,384 samples; PCM/float RIFF WAV (no RF64). Up to 384 evenly distributed 8192-sample Hann windows; displayed coverage is the analyzed fraction, not a confidence score. The server API only runs synthetic examples and rejects file inputs. For original-versus-encoded comparison, see [Codec Artifact Detector](https://elysiatools.com/en/tools/audio-codec-artifact-detector). ## Inputs - **Try synthetic signals** (select) ## When to use - Screening downloaded or archived FLAC and WAV tracks for telltale 16 kHz to 20 kHz brickwall cutoff filters. - Checking whether high-frequency energy extends smoothly to the Nyquist limit or terminates abruptly. - Testing detection heuristics against synthetic broadband and low-passed reference audio. ## How it works - Select a reference signal under 'Try synthetic signals' ('Broadband noise' or 'Legitimate low-pass audio'), or select a local FLAC or WAV file within 100 MiB and 60 minutes. - The local worker decodes the audio and evaluates up to 384 distributed 8192-sample Hann windows between 8 kHz and 192 kHz. - Inspect the interactive spectrogram, power spectrum, and the percentage of analyzed coverage. - Review the JSON verdict ('suspicious' or 'no-obvious-traces') and save the spectrum PNG or report data for your records. ## Use cases - Library intake triage: Screen imported FLAC releases to flag potential lossy upconverts before cataloging them into high-resolution collections. - Mastering chain inspection: Examine WAV exports to verify whether aggressive brickwall anti-aliasing or master bus filters introduced sharp cutoff shelves. - Heuristic verification: Run the built-in synthetic noise profiles to observe how the detector handles wideband energy versus abrupt low-pass filter slopes. ## Frequently asked questions ### Does a 'suspicious' verdict mean the audio is definitely a lossy upscale? No. A 'suspicious' result indicates a persistent, sharp high-frequency cutoff across sampled windows, which can also be caused by intentional low-pass filters or vintage recording equipment. ### Does 'no-obvious-traces' confirm the recording is genuine lossless? No. High-bitrate lossy encodes, gentle rolloff curves, short tracks, or unsampled sections can escape detection, and the tool never certifies lossless provenance. ### What audio formats and specifications are supported? Native FLAC (with known length, metadata up to 2 MiB, and block sizes up to 16,384 samples) and PCM/float RIFF WAV files up to 100 MiB, 60 minutes, mono or stereo, from 8 kHz to 192 kHz. RF64 is not supported. ### Can I upload files to the server via the API? No. The server API only runs synthetic demo signals and rejects file uploads; audio file screening is executed entirely in your local browser worker. ### Does this tool verify FLAC MD5 hashes or detect effective bit depth? No. It screens only for spectral bandwidth cutoffs and does not verify FLAC MD5 checksums, container bit depth, or codec-specific MDCT fingerprints. ## Related tools - [Hearing Safety Checker](https://elysiatools.com/en/tools/audio-hearing-safety-checker): Estimate your listening-exposure risk against NIOSH (85 dBA/8h, 3 dB exchange), OSHA (90 dBA/8h, 5 dB) and WHO-ITU H.870 weekly allowance — enter level, duration and sessions, or upload the audio you listen to for measured duration and loudness. - [Audio Chord Progression Detector](https://elysiatools.com/en/tools/audio-chord-progression-detector): Estimate an audio file's chord sequence locally and download CSV, JSON, SVG, and method notes in one ZIP. - [Audio Digital Release Packager](https://elysiatools.com/en/tools/audio-digital-release-packager): Package an album for digital distribution: distributor-profile compliance checks, cover-art validation, MP3 previews, FLAC archive copies and a delivery ZIP with a README and machine-readable manifest. - [Bit Depth Analyzer](https://elysiatools.com/en/tools/bit-depth-analyzer): Inspect container precision and per-channel integer low-bit occupancy; download an offline ZIP report. - [THD Analyzer](https://elysiatools.com/en/tools/thd-analyzer): Measure single-tone harmonic distortion per channel and download a ZIP report. - [Batch Audio Converter](https://elysiatools.com/en/tools/audio-batch-converter): Convert multiple audio files between different formats like MP3, WAV, FLAC, AAC, OGG, Opus with quality settings and batch processing - [Audio Codec Swap](https://elysiatools.com/en/tools/audio-codec-swap): Change the codec of an audio file within a chosen output format - [Audio Format Converter](https://elysiatools.com/en/tools/audio-converter): Convert audio files between different formats like MP3, WAV, FLAC, AAC, OGG with quality settings and volume adjustment ## Samples - [Copyright-Free FLAC Audio Samples](https://elysiatools.com/en/samples/flac-samples): Lossless FLAC audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music - [Copyright-Free WAV Audio Samples](https://elysiatools.com/en/samples/wav-samples): Uncompressed PCM WAV audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music - [Copyright-Free MP3 Audio Samples](https://elysiatools.com/en/samples/mp3-samples): Collection of royalty-free audio samples for testing and development purposes including nature sounds, meditation music, and ambient audio - [Speech Learning & Safety Audio Samples](https://elysiatools.com/en/samples/audio-learning-safety-samples): Deterministic synthetic WAV inputs for pronunciation comparison, dictation preflight, alert degradation, and voice privacy tools. ## Related content - [FLAC/WAV Source Screening and Evidence Handoff](https://elysiatools.com/en/hubs/lossless-audio-source-screening-and-evidence-handoff): Screen suspected lossless audio, inspect spectral and integer-bit evidence, use reference comparisons only when justified, and deliver a traceable review without claiming authenticity.