panels

oscilloscope: raw wave shape, one ~43 ms trigger-locked window.
waveform: scrolling loudness (min/max) over time.
spectrogram: scrolling frequencies over time; colour is loudness (dB).

window

Sets the spectrogram's frequency detail — the waveform is unaffected.
narrow: 2048-pt FFT, ~23 Hz bins, ~43 ms window: separates harmonics (vowels, pitch).
broad: 256-pt FFT, ~188 Hz bins, ~5 ms window: catches bursts and transients.
A new column lands every ~5 ms (the hop); each is an FFT of the most recent window. Narrow's long window overlaps heavily column-to-column (smooth in time, sharp in pitch); broad's short window stays crisp in time but blurs pitch — the classic time/frequency trade-off. The hop is held ≤ the broad window so no audio is skipped between columns.
(Live values for this device's 48 kHz sample rate.)

range

full: 0 Hz to Nyquist (½ the sample rate, ~24 kHz).
0–8k: zoom to the speech band: formants and fricatives.

scale

log: even octaves.
linear: even Hz, so harmonics form an even ladder.

VU & fader

Peak loudness meter (dB); the fader sets level / mic gain.