This thread is an index to various other threads and references on the early JBL 4-way monitors.
From the L250 profile on this site:
The four-way concept allows for very wide dynamic range since the individual drivers are called on to reproduce a relatively narrow range of frequencies and therefore the overall system can handle more power. Within their narrow range, each driver can be fine tuned in the network design to result in an inordinately flat response ...a 4-way concept that Greg Timbers pioneered in the 4315 monitor of 1974.
The 4343 is a second vision of the "big" 4-way Studio Monitors - it was preceded by the 4340/4341 series and used the same drivers, but in a somewhat larger cabinet:
the 4343 cabinet is 41 3/8 x 25 in x 17 1/8 with a net weight of 175 lbs
the 4341 cabinet is 37 3/4 x 23 3/4 x 19 3/4 and weighs "just" 160 lbs!
The difference is actually in the midrange chamber for the 10" driver - the 4341 chamber is 0.3 cu ft., the 4343 chamber is 0.5 cu. ft.
One notable feature - the baffleboard is split into two panels - the lower panel contains the LF 15 woofer, the upper panel can be rotated 90 for horizontal placement. It also has both a left and a right mounting hole for the 2405 slot tweeter (the unused hole to be capped) thus allowing mirrored Right-left speaker imaging.
The top image with 4 JBL monitors is from a 2003 photo Tom Loizeaux had posted ( I edited the image slightly just to add the model numbers). Tom was a big fan of the JBL Monitors and always had a helpful tip or friendly comment to share. He passed unexpectedly in early 2007 and we miss him.
The next picture is from a thread from John Reissen, master restoration whiz -
the image is great because it shows a 4343 in the back, with a smaller 4341 in front
The lower image is from another Reissen project showing a restored 4343 sans grill ...
I highly recommend you click the link to go see what they looked like BEFORE restoration - the man is amazing!
The bottom image is from the JBL fan site http://jbl43.com/