Before the show.

Connect and calibrate

Use HTTPS or localhost. Select the mic/interface and connect, then choose its exposed input channel. Input is never monitored to speakers. With a suitable measurement mic and acoustic calibrator, enter the known reference level on Monitor and capture two steady seconds. Set physical gain first and keep it unchanged. Software gain boosts signal and noise together; keep recording peaks below 0 dBFS.

Save calibration profiles in Settings. Restoring requires the same device, channel, sample rate and software gain; verify physical gain yourself. Input/gain changes clear calibration. A capture, clear or profile restore starts a new segment in an active log. All calibrated acoustic values are estimates. A/C filters are alpha approximations with high-frequency warping; this is not a certified sound level meter.

Choose your view

Analyzer / Ring-Out, Monitor & Log, Generator, Recorder, Logs and Settings share one audio engine. Recording and logging continue as you switch internal views. RTA On/Off and Keep running control FFT work independently. Expand controls hides setup/sidebar; Fullscreen uses the browser feature when supported. Shared stop controls remain at the bottom.

Monitor the room

Select A/C/Z weighting and Fast (125 ms), Slow (1 s) or rolling Leq. The engine processes samples continuously, rather than sampling the display. Set your own threshold and approach/well-over margins; colours and text indicate four warning stages. Defaults are not safety/legal recommendations. Digital measurements remain dBFS until an acoustic calibration is captured. Band trend highlights dominant energy using ten octave-spaced third-octave filters; it does not assign individual band limits.

Log and inspect

Choose a 1/5/10/30/60 second interval, name the session and start logging. Interval energy averages and detector maxima include all captured samples. Notes and threshold/calibration changes are stored. Local checkpoints are written about every ten seconds and on stop. In supporting browsers Auto-save to file commits complete JSON checkpoints to a chosen file; otherwise download a session manually. Local storage and browser uptime are not guaranteed. Keep the device awake, and download a portable copy.

In Log Viewer open JSON, select a local checkpoint or view the current session. Use the two timeline handles or exact times; choose weighting/trace, filter by level or segment, and export selected rows to CSV. Click the graph or a row to inspect its band trend. Whole intervals are selected by their end times. Mixed calibrated/digital segments are clearly labeled; choose one segment for a meaningful level summary.

Ring-Out assist

Enable Ring-Out with a live input. Persistent narrow peaks must exceed the floor/prominence for 700 ms. Optional auto analysis gain helps quieter peaks cross the analysis floor, with a selectable ceiling, gradual rise and a silence gate. It only adjusts displayed/detected FFT data: recording, physical interface gain and calibrated monitoring stay independent. Noise and sustained musical notes can trigger candidates. Confirm by ear; no EQ or PA gain is controlled.

Match a tone by ear

Use the FULL / FINE / VERY FINE selector switch with the logarithmic slider. CENTER returns FULL to 1000 Hz; in either fine mode it centres the range on the current frequency. Frequency readouts and entries use whole Hz. Running sweeps animate the full-range slider and a progress bar from the audio clock, then restore the chosen range. Numeric entry and presets remain available. Play/Stop is immediate; Escape also stops output. Start with low hardware volume. Sweeps stop on the audio clock. Stop-on-hidden is optional in Settings; output always starts off on a new visit. Tone/player output is blocked during audio recording.

Keep the take

Recorder captures the selected mono input. Its live RMS/peak meters, signal/overload status and basic RTA help check incoming audio, even with the detailed RTA off. These show the signal after manual software gain and exclude Ring-Out analysis assist. The basic RTA pauses outside Recorder while the take continues. Stop creates a player and download. Import local audio for playback. Takes are limited to 15 minutes/about 128 MB; codec/format depends on the browser. Audio takes live only in tab memory and are separate from saved level logs. Download before leaving.

Laptop first, tablet after testing

The intended chain is a measurement mic, interface and laptop with an acoustic calibrator. USB-audio tablets can work where the OS/browser exposes the input, but screen locking, sleep, permissions and file APIs vary. Interruptions are marked and unavailable periods are excluded; no uninterrupted background capture is promised. Test your actual setup against a trusted meter before relying on it.