[TenTec] INRAD Filter Question

[Ken Brown]

k6se at juno.com wrote:

>You will hear any narrow CW filter will "ring" if you have your
>sidetone/spot pitch (i.e., CW offset) set too high.  Set it at a lower
>pitch and you won't hear the "ringing".
>
>73, de Earl, K6SE
>
This makes no sense to me. I am not claiming it to be untrue, however I 
do not understand how or why it would be true. Can someone explain if 
and why the above is really the case?

Ken N6KB