I just re-read my post, and I don't like it. I could edit it, but figured it would make more sense to leave it.
I really shouldn't say the L100/4311Bs 'stink'. That is unnecessarily harsh. What is true about them is that they color the sound very dramatically. That heavily colored sound may be your cup of tea; certainly many people love them. But for me, I need a more neutral speaker.
And, for what it's worth, I have spent hours tweaking both the L-pads in the speaker and the eq on my amp (Pioneer SA-9500II, which has a four band eq) , and I cannot get them anywhere close to neutral sounding. There is a very awkward peak in the upper midrange, and due to a very weak crossover design the L-pads can do almost nothing to tame it.
Greg: What I have read, although I cannot point you to the source, is that the 4311Bs were a consumer monitor. They were a less expensive way for a 70s consumer to get a speaker in his house that claimed to be a studio monitor. But they are functionally identical to a L100. They have a very simple crossover that does little to control the sound, and actually creates that sharp peak in the upper midrange. My plan is to build new crossovers for mine. I suspect they could be much better speakers with a more tightly controlled frequency allocation.