JBL drivers were used extensively in horn loaded cabinets, but they were professional models seldom seen by the public (as they were mostly hidden behind theatre screens) and were never actively promoted for home usage, as opposed to the Altec A7, for instance. D130s, as well as the rest of the D series and E series, were all originally designed and marketed as musical instrument drivers, with their aluminum domes intended to extend the midrange response. There were/are many cases where the D and E series shared their frame and motor structures with other models that had different specs for different applications.