[FFmpeg-user] 'equalizer' audio filter

[Darkmoon]

I read the entry for this filter in the User Guide, then searched the 
web when I found the Guide entry mostly limited to identifying options 
for the filter, with little explanation of how the options actually 
function, and how they are to be used to create an actual "equalizer." 
What I found was no help either to a casual user who is not conversant 
with concepts of audio engineering (like "Q-Factor" or "slope," and how 
to determine what values to use in a filter). I hope I can frame my 
question a bit more clearly than what I found in my search.

I would like to use 'equalizer' in the manner of a simple graphic 
equalizer, complete with band sliders that have '0 gain' center 
positions. My ideal comand-line 'equalizer' filter would take a series 
of "band=gain" pairs, where each "band" would represent a slider, and 
"gain" the position of each slider. "Gain" would default to 0 if a 
specific "band" is not identified, equivalent to the center position of 
a slider on a graphic equalizer.

Is there a way to use ffmpeg 'equalizer' in this manner? How would it 
be done? What are some sane and practical values for setting the center 
and width of each band (or where can I find that info)? Some examples 
would be lovely. Thank you...

Jeff