I have a friend who wants to built a three way speaker with horns. The speaker I built uses a JBL 2235H woofer, Altec 802-8G on a 511B horn and JBL 077 tweeter.Rather than try and duplicate mine, he would like to build something of his own in a similar design. Besides the Altec setup for the mids, what recommendations do you have for vintage or newer mid horn?