Audio Spectrum Analyzer
Analyze audio frequency spectrum entirely in the browser. Drag-and-drop or pick an audio file, decode with Web Audio API, choose FFT size (6 presets: 256/512/1024/2048/4096/8192) and window function (4 presets: hanning/hamming/blackman/rectangular), render a real-time spectrum on Canvas, find peak frequencies, compute energy in 7 standard frequency bands (sub-bass, bass, low-mid, mid, high-mid, presence, brilliance), dBFS conversion, magnitude calculator, exponential smoothing, 4 color palette presets, text report, CSV export, history (localStorage), shareable URL, summary stats. 100% client-side.
About Audio Spectrum Analyzer
Analyze audio frequency spectrum entirely in the browser. Drag-and-drop or pick an audio file, decode with Web Audio API, choose FFT size (6 presets: 256/512/1024/2048/4096/8192) and window function (4 presets: hanning/hamming/blackman/rectangular), render a real-time spectrum on Canvas, find peak frequencies, compute energy in 7 standard frequency bands (sub-bass, bass, low-mid, mid, high-mid, presence, brilliance), dBFS conversion, magnitude calculator, exponential smoothing, 4 color palette presets, text report, CSV export, history (localStorage), shareable URL, summary stats. 100% client-side. Everything runs locally in your browser — your data never leaves your device.
How to use
- Enter your input in the tool above.
- Adjust any options to your preference.
- Use the Copy or Download buttons to save the result.
- Everything happens locally — your data never leaves your browser.
FAQ
How does the audio spectrum analyzer work?
Drop or pick an audio file. We decode it with the Web Audio API into raw PCM samples. For real-time visualization we route a BufferSourceNode through an AnalyserNode and draw the frequency spectrum on a Canvas. For static analysis we run a pure-JS radix-2 FFT over windowed segments of the decoded samples and compute peak frequencies and band energies.
What FFT sizes are supported?
Six power-of-two presets: 256, 512, 1024, 2048, 4096, and 8192. Smaller sizes give faster, smoother visualizations; larger sizes give better frequency resolution. The validator accepts any power of two between 32 and 32768.
What window functions are available?
Four standard windowing functions: Hanning, Hamming, Blackman, and Rectangular (no window). Windowing reduces spectral leakage at the cost of slightly wider peaks. Blackman has the strongest leakage suppression; Rectangular the weakest.
Which frequency bands are analyzed?
Seven standard bands: sub-bass (20–60 Hz), bass (60–250 Hz), low-mid (250–500 Hz), mid (500 Hz–2 kHz), high-mid (2–4 kHz), presence (4–6 kHz), and brilliance (6–20 kHz). Energy per band is summed from the FFT magnitudes and reported in dBFS.
What extra features does this tool have compared to others?
(1) 6 FFT size presets. (2) FFT size validator (power of 2, 32–32768). (3) 4 window function generators. (4) 7 standard frequency bands. (5) FFT bin ↔ frequency converters. (6) Peak frequency finder (top N). (7) Band energy calculator. (8) dBFS converter. (9) Magnitude calculator (sqrt(re²+im²)). (10) Exponential smoothing applier. (11) 4 color palette presets (rainbow/heat/cool/mono). (12) Text report renderer. (13) CSV export. (14) History (localStorage, last 20). (15) Shareable URL settings. (16) Canvas-based real-time spectrum visualization.
Is my data sent anywhere?
No. The audio file you load, decoded samples, FFT output, and reports never leave your browser. All decoding happens via the Web Audio API locally. Analysis metadata in history is stored in localStorage on this device only.
Related tools
Audio Bitrate Calculator
Calculate audio bitrate, file size, duration, and quality metrics entirely in the browser. Supports PCM/WAV, FLAC, ALAC, MP3, AAC, OGG/Vorbis, and Opus. Compute bitrate from sample rate × bit depth × channels (PCM), estimate FLAC/ALAC compression (50–60% of PCM), map lossy quality presets (low/medium/high/voice/music) to typical bitrates, compute file size from bitrate × duration, calculate streaming bandwidth requirement, reverse-calculate required bitrate from target file size, and score quality 0–100. Includes 7 sample rates, 5 bit depths, 4 channel layouts, 7 formats, 5 quality presets, side-by-side format comparison, text/CSV exports, history (localStorage), shareable URL, summary stats. 100% client-side.
Audio Converter
Convert audio files between formats entirely in the browser. Decode with Web Audio API, re-encode to WAV (PCM 16-bit), WebM/OGG (via MediaRecorder), or MP3 (via MediaRecorder with WAV fallback). Multi-format output, 4 bitrate presets, 6 sample-rate presets, mono/stereo channel selection, pure-JS 44-byte RIFF WAV header builder, Float32 to 16-bit PCM converter, file-size estimator, quality score calculator (0-100), lossless-vs-lossy compatibility checker, smart filename generator, conversion history (localStorage), shareable URL, drag-and-drop, and summary stats. 100% client-side.
Audio Equalizer
Apply a 10-band graphic EQ to audio entirely in the browser. Drag-and-drop or pick a file, decode with Web Audio API, adjust the gain (-12 dB to +12 dB) on each ISO-standard band (31, 62, 125, 250, 500, 1k, 2k, 4k, 8k, 16k Hz), apply via a chain of peaking BiquadFilterNodes in an OfflineAudioContext for batch processing, and re-encode as a 16-bit PCM WAV (pure-JS encoder). 10+ preset library (flat, bass-boost, treble-boost, vocal-boost, loudness, rock, pop, jazz, classical, podcast), 3-band & 5-band simplified modes, 7 gain presets per band, default Q factor 1.41, gain validator, filter-chain config builder, file-size estimator, text + CSV report, history (localStorage), shareable URL, summary stats. 100% client-side.