 As a result, pretty well every U.S studio had a set of 604's and every European studio a Tannoy Dual Concentric or two.However, in 1959, at the height of its industry dominance, Altec made the mistake of replacing the 604 with the 605A Duplex, a design widely regarded as inferior to its predecessor.There was a backlash from some record companies and studios and this allowed Altec's competitor, JBL (a company originally started by 604 designer James B. Lansing), to make inroads into the pro monitor market.