8 Free Audio Analysis Tools Every Producer and Developer Needs
If you’ve ever uploaded a track to Spotify only to find it sounds quieter than everything else, you’re not alone. The reason: streaming platforms normalize loudness to specific LUFS targets — Spotify at -14 LUFS, YouTube around -14 to -15, broadcast TV at -24. Your mix sounding “right” on your monitors doesn’t mean it meets the target.
That’s just one of the gaps these eight free tools fill. They cover the full audio intelligence stack: noise cleanup, loudness measurement, key and tempo detection, stem separation, and visualization. No signup, no paid tier. Just open the browser and go.
1. Audio Noise Reducer
What it does: Strips background noise from any audio file — hiss, hum, room rumble, you name it.
Background noise is the first thing that kills a recording. A field recording with traffic in the distance. An interview mic picking up HVAC. A podcast recorded in a bedroom with a laptop fan. The Audio Noise Reducer handles all of it.
It offers six algorithms: the FFT-based afftdn (your go-to for general noise), a high-pass filter for low-frequency rumble, a low-pass filter for high-frequency hiss, and three presets — mild, combined, and aggressive — for different severity levels. You tune the reduction level on a 0.1–1.0 scale and set your frequency boundaries.
The output formats include MP3, WAV, FLAC, AAC, OGG, and M4A. Drop in your file, pick your algorithm, and download the cleaned result.
When to use it: Cleaning up field recordings, restoring old audio, preparing interview audio for transcription, or any scenario where the signal-to-noise ratio needs improvement.
2. Audio LUFS Meter
What it does: Measures loudness in LUFS using the EBU R128 / ATSC A/85 standard.
LUFS (Loudness Units Full Scale) is the unit of choice for broadcast and streaming compliance. The Audio LUFS Meter runs FFmpeg’s ebur128 filter and returns four metrics: integrated loudness (the overall average), short-term maximum (what it sounds like in the loudest moment), momentary maximum (peak over a 400ms window), and loudness range (LRA — the dynamic swing of the track).
Spotify targets -14 LUFS integrated with an LRA under 12. YouTube is similar. Broadcast is -24. If you’re mastering for any of these, you need these numbers — not just a peak meter.
When to use it: Checking whether your mix meets platform requirements before upload. Diagnosing why a track sounds inconsistent across scenes in a video edit. Any mastering or mixing work where you’re targeting a specific loudness standard.
3. Audio Key Detector
What it does: Identifies the musical key and mode (major/minor) of a track.
Mixing in the wrong key relative to underlying elements creates dissonance. The Audio Key Detector analyzes chroma features — the distribution of pitch-class energy across the 12-note chromatic scale — and matches them against established major and minor key profiles using Pearson correlation.
It works on up to 240 seconds of audio (default: 90), returns the best match plus the top 5 candidates with confidence scores. If you’re layering sound effects, composing against a reference track, or working on a remix, knowing the key is non-negotiable.
When to use it: Keying original compositions to reference tracks. Checking whether stock music or library audio is in a compatible key before layering. DJing or live performance preparation.
4. Audio BPM Detector
What it does: Detects the tempo (beats per minute) of a music track.
Tempo is the heartbeat of a project. The Audio BPM Detector downmixes to mono, analyzes up to 300 seconds of audio using beat-tracking via the MusicTempo algorithm, and returns the BPM value plus the total beat count.
Beat trackers sometimes return half or double the actual BPM for tracks with slow or fast tempos. The beat count output helps you catch this — a 3-minute track at 70 BPM should have roughly 210 beats. If the count is around 105, you know it’s actually 140.
When to use it: Syncing audio to video edits that need a specific tempo. Preparing DJ sets. Checking whether a loop or sample matches the project’s tempo before importing.
5. Audio Dialog Isolation
What it does: Separates audio into vocal and accompaniment stems using Spleeter or MDX/Demucs models.
The Audio Dialog Isolation tool runs your file through Spleeter (Deezer’s 2-stem model) or Demucs/MDX (Meta’s newer separation engine) and outputs two files: vocals and accompaniment, packaged as a ZIP.
This matters more than people realize. Isolate vocals to run lyrics-to-timing alignment on a podcast. Pull the instrumental stem for a karaoke version. Use the accompaniment track for remixing. Process the vocal stem through a compressor or EQ without affecting the backing track.
Both engines handle WAV, FLAC, MP3, M4A, AAC, OGG, and Opus inputs, and you can specify the output format.
When to use it: Creating karaoke tracks. Running transcription on isolated vocals. Sound design where you need one element isolated. Podcast producers who want to re-use interview audio with different music beds.
6. Audio Stem Mixer
What it does: Mixes multiple stems and exports three versions: normal, vocal up (+3 dB), and vocal down (-3 dB).
Once you’ve separated stems using the tool above (or pulled stems from a session), the Audio Stem Mixer lets you blend them with adjustable vocal prominence and outputs all three versions in a single ZIP download.
You specify which stem is the vocal (by index), set the gain offset for vocal-up and vocal-down versions (up to ±12 dB), choose the output format (MP3, AAC, M4A, OGG, Opus, FLAC, or WAV), and the tool handles the rest — including a limiter to prevent clipping when you push the vocals up.
When to use it: After dialog isolation, quickly producing instrumental, acapella, and TV-versions of a track. Stem mixing for film/TV where dialogue clarity varies across scenes. Creating alternate mixes for different listening environments.
7. Audio Spectrogram Generator
What it does: Renders a spectrogram image from an audio file — visualizing frequency content over time.
The Audio Spectrogram Generator runs FFmpeg’s `showspectrumpic` filter and produces a PNG. You control width, height, and color scheme — eight palettes available including magma, viridis, plasma, and fire.
A spectrogram shows you what a waveform doesn’t: where specific frequencies live in time. The horizontal axis is time, vertical axis is frequency, color is amplitude. You can see the fundamental frequencies of instruments, identify resonance problems, spot noise, and visually verify that a low-pass filter is actually cutting where you intended.
When to use it: Visual analysis of recordings for education or debugging. Checking whether a frequency issue in a mix shows up consistently across the track. Acoustic analysis of room recordings. Generating visual assets for articles or presentations.
Try Audio Spectrogram Generator →
8. Audio Loudness Report (LUFS)
What it does: Generates a broadcast-grade loudness report including integrated LUFS, true peak, and loudness range (LRA).
Where the LUFS Meter gives you real-time measurement, the Audio Loudness Report gives you the official numbers for compliance documentation. It runs FFmpeg’s `loudnorm` in print-json mode and returns: input integrated loudness (I), true peak (TP), LRA, threshold, and target offset.
These are the exact values required for loudness normalization standards. If you’re delivering to a broadcaster, streaming platform, or any institution with loudness requirements, this report is your paper trail.
When to use it: Pre-delivery QC for broadcast or streaming. Generating documentation for clients or platforms that require loudness certification. Comparing the loudness characteristics of different masters.
The Gap These Tools Fill
Audio analysis used to require a DAW, a plugin suite, or an expensive metering tool. The stack here runs entirely in a browser, handles common formats, and produces output you can act on immediately.
The combination is useful beyond just music production. Video editors dealing with audio sync and loudness. Podcast producers cleaning up remote recordings. Developers building audio pipelines who need quick metrics without spinning up a full processing environment. Researchers working with acoustic data.
All eight tools are free, browser-based, and ready to use at ElysiaTools.com.
