What JBL fans are you talking about? You can only go so far with marketing and then the product has to stand on its own.
And what is this "ubiquitous Altec studio monitor" you mention? If the 4310/4311 came in like a steamroller and displaced most of them, the Altec monitor must have had a serious deficiency just waiting to be exploited.
Ok, here's the history.
http://www.audioheritage.org/html/history/jbl-pro/1960s.htm
Nutshell, a great driver series, the Altec-Lansing 604 duplex speakers, were installed in fairly large cabinets and were used as monitors by industry professionals in music, studio, and film production. The fairly famous A7 was also developed by Altec-Lansing to provide similar sonic reproduction in theatres and performance venues of the 50's and 60's. These 604D series drivers and A7's are still highly prized speakers today, and many like/love they way they sound and work. So these are the speakers that literally everyone was using Circa early to mid 60's across the US. Were they with "serious deficiency"? Sure, but at the time, they were state of the art with respect to what was needed, generally smooth but limited output on the extremes of frequencies, high output sensitivity (especially with generally limited output tube amps of the day), and pretty consistent performance and sound characteristics (important for producers, engineers, and musicians using these tools). Was it high fi? Well, for some yes, but few knew, could buy, or even house such large and expensive speakers.
Ask around today though about the 604D and revised 604E duplexes and A7's and for such "deficient" speakers, they sure do get a high value and rating in today's markets, domestic and abroad.
Due to a critical mistake on Altec's part in making the cheaper 605 driver a priority for monitors, the industry didn't like them. Enter JBL and the first attempt making a large studio monitor based on the D50SMS7, essentially an S7 load (like a JBL Olympus with single woofer) in an industrial cabinet. What helped them was Capitol Records liking what they heard (a somewhat smoother frequency response) and they bought the successor 4320 speaker (consumer L200). The 4310/4311 was designed to specifically sound like the Altec-Lansing monitor that everyone was using but in a smaller package (could fit more into a soffit space for the new multitrack recording process. Here then could studio's now replace their much older Altec units with newer and in some cases, better sounding JBL monitors. Couple that with revised modern looks and it became the thing to do, especially with new bands in the 60's coming into the recording scene. The old Altec's still looked like that monitor in Les Paul's studio of the mid to late 50's (nothing wrong with that but upgrading and sales proved the modern looks were important).
So the 4310/4311 speakers did what they were designed to do - work and sound like an industry standard so people were familiar with them and could do what they had always done. And they sold a ton of them and the consumer L100 was a similar success. Later versions of Studio Monitors had much better, flatter, frequency responses as well as tuning into issues of directivity, power response, frequency extension, etc. (434x and 44xx series). That all came from very good engineering, testing, manufacturing, and yes, sales and marketing. JBL continues to do all of those things in the pro market, even today, with the LSR series of monitors, the Vertec and Architectural Series, as well as many other product lines to address all needs, niches, and budgets.
Do all the speaker sound "good or great"? Not always, but these are professional products to do professional (and semi-pro, amateur) work. Are they HiFi? Only people can judge that for themselves. But very few companies in the loudspeaker business have been around for as long, have a long history of engineering prowess and mostly manufacturing excellence as JBL. Sure there's lots of other smaller or limited line companies that make great loudspeakers. But JBL is one of the best out there, IMO.
I'll select out the relevant part of the link above for the next post.
Bart
