Spek review
A free, open-source desktop tool for offline spectrogram and codec inspection.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Spek is a free, open-source desktop application for analyzing recorded audio files through spectrograms. It is designed for users who need to inspect audio files offline, review codec and signal information, or create spectrogram images for documentation and comparison. Spek runs on GNU/Linux, Windows, and macOS, and supports common lossy and lossless formats through FFmpeg. Its interface includes drag-and-drop support, common audio-file associations, and rulers for time, frequency, and spectral density.
Its main strength is the depth of its file-based spectrogram view. Spek uses multi-threaded signal processing and displays the codec name and audio signal parameters alongside the visualization. Users can adjust spectral-density range and dynamic-range limits, switch audio streams and channels, and change the DFT window size and function. These controls make it suitable for examining frequency content and codec behavior rather than simply viewing a fixed waveform. Spectrograms can also be saved as image files, which supports reports, cataloging, and technical discussions.
Spek is less suitable for live monitoring, recording workflows, or broader audio editing because its published category specifications identify offline file analysis and no real-time analysis. Users who need a desktop utility for examining existing files should find its narrow focus appropriate, especially when a free and open-source tool is preferred. Users who need live analysis or production features should choose an alternative built around those workflows instead. The latest listed version is 0.8.5, while the Windows and macOS installers are marked beta.
Spek pros and cons
- Where it wins
- Free and open source on Windows, macOS, and Linux
- Supports common lossy and lossless formats through FFmpeg
- Exports spectrograms as images with adjustable analysis settings
- Where it doesn't
- No real-time analysis for live audio or active sessions
- Focused on offline file inspection rather than broader audio production
- Windows and macOS installers are marked beta
Spek fact sheet, pricing and score →
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