Tue Mar 19 17:37:00 EDT 2013

What does an LP/HP/BP response look like?

Is there any kind of visual quality that can distinguish impulse
responses of LP/HP/BP?  They are all sums of damped exponentials, so
where is the difference?

Qualitatively, one of the key points seems to be how phase and damping

 - The DC response is determined by the average, so when most of the
   response is above zero, the response will be low-pass.

 - If the response doesn't jump from 0 immediately, this shows
   inertia, a property of low-pass behavior.

Probably step responses are a lot easier to interpret since they are a
bit more intuitive to grasp.