SignalKit - RTA & Audio Tools

SignalKit is a professional-grade audio analysis toolkit built for sound engineers, AV technicians, and tuning enthusiasts. Designed to be a portable replacement for stand-alone analyzers in field work, system tuning, and acoustic measurement.

REAL-TIME ANALYZER (RTA)
- Live FFT spectrum from 20 Hz to 20 kHz
- 1/1, 1/3, 1/6, 1/12, 1/24 octave bands
- A, C, and Z weighting
- Pinch-to-zoom on the spectrum chart
- Peak hold with adjustable fall time
- Save target traces and stack up to 30 for comparison
- Customizable colors (chart background, grid, bars)
- Tap any band to lock and read its level

SPL METER
- Live broadband measurement with Fast/Slow time-weighting
- Peak, RMS, and Leq (energy-averaged) readouts
- A, C, Z weighting toggle
- Calibration offset for matched reference levels

SIGNAL GENERATOR
- Pink, white, and M-noise sources
- Sine wave with user-defined frequency
- Sweep generator with 3 loop modes
- Output level picker (dBFS)
- Export signals as WAV files

MEASUREMENT TOOLS
- STI / STIPA speech intelligibility (paid add-on)
- Impulse response capture and analysis
- Polarity check tool

WIRELESS DEVICE LINK
- Pair two phones over WiFi via QR code
- One phone measures, the other displays the data in real time
- Useful when the mic position can't reach the operator

LOCAL-FIRST
- All measurements stay on your device
- Optional WAV export via local share sheet
- No account required, no cloud sync of your measurements

FREE & PRO
- The core RTA, SPL meter, and signal generator are free to use
- The free version is supported by ads
- A one-time Pro purchase removes ads (and unlocks the paid measurement add-ons)

Privacy policy: https://griswoldlabs.com/privacy/signalkit/