I can't find anything about an inexpensive high pass filter for my LFE channel. It must have a cuttoff for at least 23 HZ and it must be capable of handling a DTS or DD LFE channel from my reciever. I want to get rid of all frequencies bellow the 23 HZ range. It's ok if it is a feature on a preamp. It also must have, RCA jacks and a way to turn down or up the signals volume. Could anybody help?