Well, all I can say is that there is an exceptional single driver made by Feastrex that can be used to cover from about 60 Hz to well above 20K Hz. Actually there are two different drivers, one 5" and one 9." The 5" is the better driver and especially in the field coil version. I heard it in the Maxhorn cabinet and was thoroughly please except below 60 Hz. I have spent a good part of my audio life trying to mate subwoofers with such "not full range" speakers. I don't think it can be done.
These drivers are very expensive. I think $39k per pair. I cannot imagine anyone buying them at that price.
These drivers are very expensive. I think $39k per pair. I cannot imagine anyone buying them at that price.