I am building sealed JH3 3-way mains which have an F3 of 65 and a F10 of 37. I think they will need a sub. This is for music only. My reciever has a neat feature where it can drive a passive sub with 70 watts but the crossover is fixed at 80hz. Do you think I would have a good integration with the mains? or should I plan on buying a plate amp that has an adustable crossover?