Frequency Analyzer vs SpectraHold

Turn your iPhone into a calibrated sound level meter, spectrum analyzer, and noise dosimeter. Built for fieldwork, inspections, and everyday measurements. Whether you are tuning a room, surveying noise on a job site, or checking workplace exposure, Frequency Analyzer gives you the data you need. REAL-TIME SOUND LEVEL METER - Live SPL readout with A, C, and Z weighting plus linear response - Fast (125 ms), Slow (1 s), and custom time averaging - Min, max, average, peak, and LAeq displayed continuously - Configurable reference calibration so your readings match a known source SPECTRUM AND SPECTROGRAM - Real-time FFT spectrum from 20 Hz to 20 kHz, linear or logarithmic axis - Scrolling spectrogram with selectable colormap and peak-hold markers - Octave-band view at 1/1, 1/3, 1/6, or 1/12 resolution - Classic oscilloscope waveform with adjustable time window - Amplitude-over-time history for slow trends across hours NOISE DOSIMETER Track noise exposure against NIOSH and OSHA criteria or a custom standard you define. The app accumulates dose throughout your shift, projects your 8-hour exposure, and reports the time-weighted average. Add event notes and export a PDF report with stats and graphs. REPORTS AND EXPORT - Reference tone generator from 20 Hz to 20 kHz for signal checks - CSV time-series exports for spreadsheets and analysis tools - Spectrogram PNG snapshots at configurable resolution - PDF reports with session statistics, charts, and event markers - Calibration and preferences stored locally on your device PRIVATE BY DESIGN Everything runs on your device. There is no account, no login, and microphone audio does not leave your phone. Sessions, notes, calibration data, and preferences stay in local storage. HOW TO USE 1. Grant microphone access and run the quick calibration walkthrough 2. Choose Analyzer, dB Meter, or Dosimeter from the tab bar 3. Use spectrum, spectrogram, waveform, octave, or amplitude history 4. Watch dose, peak, average, and frequency readings as you measure 5. Export CSV, PNG, or a PDF report when you need results Built for acousticians, safety officers, HVAC inspectors, musicians, and students who want serious acoustic measurement in their pocket. Free to download. Some features require a premium purchase. Privacy Policy: https://estifie.com/apps/frequencyanalyzer/privacy-policy Terms of Use: https://estifie.com/apps/frequencyanalyzer/terms-of-use

The spectrogram with memory. SpectraHold turns microphone input into a 3D spectrogram. Watch frequencies in real time, freeze the view, and explore up to 120 seconds of visual history to inspect a detail you just heard. FREEZE AND EXPLORE Tap the graph to inspect a frequency. Zoom and browse the history, then return to live analysis whenever you want. ADJUST THE VIEW Choose a visible window from 1 to 20 seconds, color palettes, and automatic or manual visual gain from −40 to +40 dB. Visual gain changes the graph without changing microphone gain. FEATURES • Real-time 3D spectrogram from 20 Hz to 20 kHz. • Adjustable history from 20 to 120 seconds. • Frequency inspection, zoom, and history navigation. • Up to two estimated peaks per region: bass, midrange, and treble. Detection does not confirm resonance. • Background capture and capture with the screen locked, while permitted by the system. • Compatible with iPhone and iPad. Audio is processed on your device. History stays in memory; no audio file is saved or uploaded. Closing the app or a system interruption may stop capture. TRIAL AND PURCHASE Download for free. Activate a free 7-day trial to access all features. After the trial, analysis stops until you purchase full access. The unlock is a one-time purchase, with no subscription or automatic charge. The local price is shown before you confirm the purchase. You can restore purchases. SpectraHold is a visual analysis tool. It does not apply equalization, automatically eliminate feedback, or replace a calibrated sound pressure level meter. Estimates depend on the microphone, device, and recording conditions.