The phenomenon responsible for this complete turn around was the rise of high power rock music. This became the most popular music genre in the 70's. Many artists and engineers began monitoring playback at ridiculous levels. For example, when The Who built their first studio in the mid 70's, they installed twelve 4350 monitors in their control room. These were the highest output monitors JBL produced, with each one capable of a sustained output of over 125db. The Altec 604 was no match for this power onslaught. Its bass and tweeter coils used 3" and 2" voice coils respectively. Compare this to the 4350 with two 4" coil bass drivers, a 4" coil midbass driver, a 4" coil midrange driver and an ultra high frequency tweeter. Power handling and output of the 604 was a fraction of the 4350.
JBL filled out the 4300 line with new medium sized 3 and 4-way monitors to cover any studio application. From the smallest nearfield, to the largest main monitor, JBL had a product. In addition to product range, JBL's 4300 series represented a significant step up in performance. In particular, the 4-way monitors achieved new levels of accuracy. The narrower bandwidth requirements for individual drivers made it easier to design them for maximum linearity. Market acceptance was immediate and worldwide. JBL's monitor sales to Europe and Asia were almost as great as domestic sales.
The 70's saw the emergence of a another new market that JBL would grow to dominate - tour sound. Again, it was not a market that JBL initially pursued. However, when the market potential became apparent, JBL was quick to capitalize.
Tour sound had its genesis in the 1960's with the rise of Rock and Roll. Initially, there were no dedicated loudspeakers for touring. Tour operators began setting up systems with small column speakers. When it was apparent that higher output loudspeakers were needed, they turned to the one industry that had such product - the cinema market. Initially, Altec was the supplier of choice due to their premier position in the cinema field. The first system to gain acceptance was the 604 Duplex. Given the known power restrictions of this driver, it wasn't long before Altec A2's and A4's were being dragged across the country for tour sound systems. The limitations in using such massive systems for mobile installations became quickly apparent. Independent contractors began designing their own boxes that had reduced size and weight, but continued to use drivers from the cinema industry.
Altec decided that this was a market that they did not want to pursue. Servicing that industry was proving very expensive. Tour operators continued to push power and output levels beyond the capabilities of the drivers. The repair of drivers grew to be more significant than initial sales, and given the low margins of the former, was of little interest to Altec.
JBL was ready to address this opportunity with two product advantages - the 375 and the Musical Instrument (MI) drivers. The 375, with its 4" coil had significantly better power handling than the competing Altec 288. The MI drivers, again with 4" coils, were even more suited than the competition since they also had ruggedized suspensions and cones. In 1971, JBL updated their "F" series MI drivers with the "K" series. This series introduced high strength epoxy adhesives and Kapton coil formers. They raised the output and power handling to levels well beyond anything the competition could handle. Very quickly JBL became the dominant supplier of tour sound companies, a position that they hold to this day.
The decade ended with JBL preeminent in
three of the largest segments of the professional sound market - MI, studio
and tour sound. One seemingly impenetrable barrier remained - Altec's near
monopoly of the cinema industry. However, the seeds had been sown for the
final assault that would ultimately breach that barrier.