Sound Spectrum Pro for Windows

SPL / LEQ Meter

Shows the SPL end LEQ sound levels in big fonts.
Choose it from the Mode menu.
The LEQ calculation time is shown at the bottom. It resets when you enter this mode.
Pressing PAUSE will not reset the averaging - it will just ignore the sound until you press RUN.
If enabled in View, also the 15-minute and 60-minute sound energies are calculated and displayed (LAeq15 and LAeq60). They become green when they are valid (the minimum needed time has elapsed).

Is a measure of the effective sound pressure, relative to the reference level of 20 µPa (microPascal).
Is expressed usually in dB SPL = 20 * log(p rms / p ref).
Is shown here as dBA (A-weighted), dBC (C-weighted), and dBZ (flat-weighted).

Is the total sound energy over a given period of time, also named Equivalent Continuous Sound Level.
Is shown here as LAeq (A-weighted), LCeq (C-weighted), and LZeq (flat-weighted), calculated over the full shown time (since start).
LAeq15 is the total sound energy (A-weighted) in the last 15 minutes.
LAeq60 is the total sound energy (A-weighted) in the last 60 minutes.

Enable LAeq15 and LAeq60 from the View menu
All the settings for FFT apply.
The smoothing time constant only applies to SPL values. LEQ values are calculated from raw data before smoothing.