I would like to come up with a method for measuring 60Hz hum. Is there a standard way of doing it? The way I thought might work is in the Amplitude Window to measure the broadband noise floor first. Then use the bandpass filter at 60Hz and see if they match. Would that work?
In the absence of an FFT capability, this is the method that gives the most meaningful results. The sliding filter in the S1 and Portable are 3rd-order IIRC, so they include some of the other noises (mainly Brownian noise) in the measurement.
In a decent piece of gear, that should be very close to what an FFT would indicate.
Remember that hum is seldom 60Hz only. There are generally significant components at 120, 180 and maybe more harmonics.
Measuring broadband noise is not strictly necessary for assessment of spot noise.
Broadband noise should be measured with a BW of 2Hz-22kHz.