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Re: Good riddance Even the best designed band-pass filter will does not produce sharp contrasts across the close frequencies. You have to balance the loss of the original signal with the sharpness of the curves of allowed outside frequency. Making the curves on the outer bands costs of the recieved freqs, not money.
I got an idea, take some Electrical Engineering classes and design that sharp band-pass filter, and you'll rake in the dough. The band passes are idealised as a trough, but in reality, the filtering effect to near freqs are not straight up and down, but actually go at an angle.