kyheng , I still not qualified to teach ppl yet...haha..juz share my knowledge learned from all sifu here...pai seh pai seh...haha...but for leisure listening like me where I have a 25X4 HU and connect to a RMS100W 6X9 speaker is ok for me...Bass still good enough for me and I didn't complain anything cause my HU too low rating...hahaha...but ok la...got money onli change the HU lo....