Bigtee got it right. Jrd351, too. The market was dominated by JBL (made on the West Coast) and AR (made in New England). Regional stereotypes (sorry) were reinforced by the conservative (flat, but a little compressed) sound of AR versus the more colorful (with ear-pleasing emphasis of highs and lows, and more dynamic) sound of JBLs, a la the respective social styles and mores.