[RWebb]

Just to clarify, I want a gizmo with a microphone on it; the mic feeds into a box (or an interface to a computer) and it then does a process called a transform (I am partial to FFT, but hey - I grew up in Louisiana), and you see (and/or can record) little bars sticking up on the screen of your laptop or device.

Each bar is set along the x-axis at a certain frequency, and the ht. of the bar on the y-axis is the amplitude of that (really those) frequency.