Crossover cascading Reply #50 – 2013-04-19 20:17:59 The folks here are an excellent source of information, but we are having a difficult time understanding why this is so difficult for you, so I will try one more time.I think the problem may be that you are under the impression that an 80 Hz low pass filter passes everything below 80 Hz and removes everything above that. While it is possible to design a filter that approximates that behavior, that is not the kind of filter we are talking about here.Most likely this would be a filter that passes frequencies below 80 Hz almost 100%, but it also passes higher frequencies to a lesser extent. 160 Hz, for example, might be attenuated to 1/2, 320 Hz to 1/4, 640 Hz to 1/8, etc. Now if you combine that with a 500 Hz low pass filter, that 640 Hz is attenuated even more. It is still not eliminated entirely, and the difference may not be audible, but it is certainly measurable.