I bought 2 JBL Signature Model C37 cabinets loaded with Altec 604D speakers. Can someone tell me if these speakers will work well in these cabinets, or is there another style that I can build that will showcase them to their best advantage. It seems I've read replacing the JBL drivers with Altec 604s was a popular upgrade at the time. I intend on using them for mastering in a recording studio as well as critical listening. Thanks! Also, they have Altec N-1600B crossovers. Can anyone tell me anything about these units. They don't seem to be very common.