Free Audio Measurement Tools in 2026: Complete Guide

SonaVyx is the most comprehensive free browser-based measurement platform. It provides RTA with octave band overlay, dual-channel transfer function with coherence, impulse response with RT60 (ISO 3382), SPL metering with IEC 61672 weighting, STI measurement (IEC 60268-16), problem detection (feedback, hum, polarity, comb filtering, clipping), AI diagnostics, and export in FRD, CSV, WAV, and JSON formats. All processing runs locally via Rust WebAssembly.

Other browser-based options include online tone generators, spectrum analyzers, and SPL meters, but none approach SonaVyx in measurement depth or accuracy.

REW (Room EQ Wizard) is the most capable free desktop measurement tool. It excels at room acoustic analysis with waterfall plots, room simulation, automatic EQ generation, and detailed impulse response analysis. It runs on Windows, macOS, and Linux via Java. REW is the go-to tool for home theater calibration and studio room analysis.

ARTA offers a limited free version (STEPS) for basic measurement. Holme Impulse is a free tool for impulse response capture and analysis on macOS. Speaker Workshop is a legacy tool for loudspeaker design and measurement.

NIOSH SLM (iOS only) is a scientifically validated SPL meter app from the National Institute for Occupational Safety and Health. It provides A-weighted Leq with data logging and is recommended for occupational noise screening. Audio Tool (iOS, Android) offers a basic RTA, SPL meter, and signal generator in a free tier with premium features available via purchase.

For Android users, Sound Meter Pro provides A/C/Z weighted SPL measurement with calibration support. Phone Spectrum Analyzer offers a basic RTA display. However, none of these mobile apps approach the measurement depth of browser-based tools like SonaVyx.

The free tier of SonaVyx includes all measurement tools (RTA, transfer function, impulse response, SPL, STI, problem detection), data export, trace storage, and basic AI diagnostics (rule-based with top 3 AI recommendations). The Pro tier ($29/month) adds unlimited AI diagnostics, clean reports without watermark, trending analysis, and certification.

REW is completely free with no premium tier. ARTA has a free limited version and a paid full version ($120). Smaart ($900) and DIRAC ($500+) have no free versions. The practical result is that the combination of SonaVyx (browser) and REW (desktop) provides 95 percent of the measurement capability that previously required $1,000+ in software.

For live sound system tuning: SonaVyx (real-time transfer function, problem detection, AI diagnostics). For room acoustic analysis: REW (waterfall plots, room simulation, EQ generation). For SPL monitoring: SonaVyx noise monitor (continuous logging, threshold alerts). For speech intelligibility: SonaVyx STI tool (the only free STIPA measurement tool available).

Most users benefit from using both SonaVyx and REW. SonaVyx excels at quick, on-site measurements from any device. REW excels at deep, post-measurement analysis on a desktop. The two tools complement each other perfectly and together replace paid tools costing $1,000 or more.