If you do an FFT of the displayed section, there appears a frequency spectrum. Samples of the waveform are taken in time-consecutive frames. Pressing the space bar or right arrow key causes the display to step in small time increments. The spectrum changes with each step. Another display is the spectrograph, which is like a colored voice print.
Time slice is a plot of amplitude versus time over a given frequency range.
That is, time slice is an impulse response, or transient response, centered in a specified frequency band. A time slice of a room measurement shows the room's early sound reflections and reverb. Rainbow mode shows three successive time slices overlaid. Once a time slice is displayed, Smaart Pro can find the decay rate of the signal. This can be done manually by drawing a decay line on the plot.