ARCQ SPL vs AudioEngineerToolkit

SPL Meter turns your iPhone or iPad into a precision sound pressure level meter for musicians, audio engineers, AV techs, and anyone who needs to know how loud it really is. Built around real-time A- and C-weighted measurement, SPL Meter shows the readings the pros actually use — not a single number, but a full panel of simultaneous metrics. MEASUREMENTS • LAS / LCS — A- and C-weighted level with SLOW or FAST time weighting • LAeq / LCeq — equivalent continuous level over your chosen averaging window • LCpeak — true C-weighted peak, instant and max-hold • TWA — time-weighted average for noise-exposure style monitoring • Instant, average, and max-hold values side by side LIVE SPECTRUM • Real-time octave-band spectrum analyzer • Drag across the display to read the level at any frequency • Double-tap to expand for a full-screen view FLEXIBLE INPUT • Use the built-in microphone or any connected USB, Bluetooth, or headset input • Multi-channel interfaces supported — pick the exact input channel • A/B capture: freeze two readings and see the difference DESIGNED FOR REAL WORK • Choose your averaging window to suit the room and the source • Custom thresholds and profiles • Clean, high-contrast layout that reads at a glance on stage or in the field • Universal — optimized for both iPhone and iPad PRIVATE BY DESIGN SPL Meter does all processing on-device. Audio is never recorded, saved, or transmitted. There are no accounts, no analytics, no tracking, and no ads. A NOTE ON ACCURACY Like any phone-based meter, readings depend on your device's microphone and are not a substitute for a calibrated Class 1/2 sound level meter for compliance work. SPL Meter is a powerful, consistent tool for monitoring, comparison, and setup — not a certified measurement instrument.

A complete set of offline calculators for audio engineers — on stage, in the studio, no internet required. No login, no ads, no tracking. ■ Electrical · Ohm's Law calculator · Power calculator · Speaker impedance (series/parallel) · dB ↔ power ratio converter ■ Delay · Distance ↔ Time ↔ Phase · Haas Effect zone finder · Multi-zone speaker delay alignment · BPM-based reverb pre-delay ■ Acoustics · Frequency ↔ Period ↔ Wavelength ↔ Quarter-wavelength · Octave band calculator · Distance ↔ time delay · Room volume calculator · Room mode calculator · RT60 reverberation time ■ Tempo & Pitch · Tap tempo (BPM) finder · Note length calculator · Playback speed ↔ pitch converter (turntable-style) · Loop BPM finder · Bar duration calculator · Sample rate / buffer size latency calculator Keep your go-to calculators in the Favorites tab and open them in one tap. Available in Korean, English, Japanese, Spanish, Simplified Chinese, German, Brazilian Portuguese and French. Runs on iPhone, iPad and Mac.