[Russell Dawkins]

At least the Rectilinears had what looks to be an appropriate sized box—and what looks to be a Philips AD-5061/M4 mid, which I bought boxes of in the early 70s to use as wide range midrange drivers in the speakers I was building. They sounded good, and I used to run them from about 120Hz to 4kHz or so.

I made a 9 driver line array with them in a 'tapered tunnel reflex' box for a singer friend who wanted a PA speaker and they sounded outrageously good for the time.
The salesman at the store where the singer was looking for a suitable matching powered board looked with barely-concealed skepticism at the box until he tested the board with a "test, one, two" followed by a "holy s**t". The tech came running out from the back of the store, saying "what was that?"
Made my day, and I've been a fan of line arrays ever since.

I believe the Advent had what was described as a 10" cone in a 12" basket and had extraordinary excursion capabilities and bass extension for the time (and price).

[dB Cooper]

Advent was definitely NOT 'mid-fi'; very familiar with them as my next door neighbor had a pair. My exposure to Rectilinear was much more limited- heard them a few times under 'Hi-Fi store' (remember those?) conditions. The Rectilinear was a complicated design but I suspect some actual thought went into it, whereas the Lafayette was more likely just as many drivers crammed into a box with the biggest woofer that would fit.

A 'mid fi' memory that just came to me: When I was in my early teens, before I got my first 'real' system, I used to hang out in the local Radio Shack where there was a manager named Joe and a guy on Tandy Crafts side who had two clamps for hands (I forget his name).  They were both really nice guys. Joe had this weird thing though: He would turn everything that affected tonal balance all the way up. Loudness control, bass, mid, treble; all of them all the way up. The sound was, as you'd expect, horrible. We used to tease him about it.   He had some respectable gear there too; I remember AR and Miracord TT's on display.

[dB Cooper]

I believe the Advent had what was described as a 10" cone in a 12" basket and had extraordinary excursion capabilities and bass extension for the time (and price).

Correct. Henry Kloss had a nonstandard cone size (9-1/2") in mind for probably the above reasons and the 12" basket saved him (and the buyer) the cost of a custom basket. Forget where I read this. Probably an Advent brochure. Unfortunately it had the same longevity shortcomings as do all foam surrounds. The surround was also concave curved rather than convex, unusual at the time.