dont understand isRange() in Minim

Hi!

Im doing sound analysis with minim and dont understand isRange() method in the BeatDetect class In the reference it says

In frequency energy mode this returns true if at least threshold bands of the bands included in the range [low, high] have registered a beat. In sound energy mode this always returns false.

I thought that by writing something like this:

if ( beat.isRange(0, 4, 2) ) aBoolean = true;

would say this:

If the there is sound with amplitude of at least 2 dB between the frequence 0-4 return true (Of course I realise though that its not the case because of the very small values)

But then I dont understand either how to switch between the fields (and what is a field?)

frequency energy mode and sound energy mode

so might be something there?

any help very much apreciated!

Heres the reference for minim (the reference for isRange() returns 404 - not found though)

code.compartmental.net/minim/beatdetect_class_beatdetect.html