In connection with my modification of the spectrogram to plot frequency on a log10 axis, I have a need to place (at least) a lower bound on the frequency. Eg looking at music, anything <10Hz is of no use and wastes chart space. I also have noticed a few requests for a feature to limit the plot to a subset of the available frequencies. So I intend to add this in the coming days.

I'm not very familiar with the sox utility, so I'm asking what's the best way of specifying the lower and upper frequencies consistent with the rest of the utility? What I propose is to use just one command line switch, eg

-R lower-freq[:upper-freq]

For example

-R 10

meaning from 10Hz -> nyquist frequency

-R 100:12k

meaning 100Hz -> 12kHz

So to generate a chart of a music file looking at frequencies 100Hz - 10kHz

sox mymusic.mp3 -n spectrogram -L -R 100:10k

Does that seem ok?

Joe.