As for the sound, we had a moderately large dedicated room for them and other high end stuff (Bose 901's were new, and making much noise, then) and I wasn't overly impressed with the Infinitys. The cound was impressive, but flashily so. Even the 901s sounded better (!?) with a big enough amplifier and with the right source material. A Decca cartridge was the most spectacular sound I heard in that room, and that was true on a considerable range of source material (all on vinyl of course. We had some Sheffield Labs recordings then, IIRC, and my memory reports that they were particularly impressive). Can't remember the amps we used that week (Phaselinear?, probably SAE) but they were 200+ wats RMS/channel, had large power meters, etc. We all spent quite a lot of time down there listening, largely to the 901s with the Decca. Pissed off store managers too... The Infinitys spent a good deal of time traveling in and out to demo for potential customers in their homes. And coming back to be refurbished with new elements.

There's another speaker from that era I remember as well. That was (!!) the Rectilinear 10 (prhaps 10a), which was a 3-way (10" woofer, 3" mid range, and a small dome tweeter). Sealed box, not very efficient. The xover from the woofer to the midrange was something like 100Hz or maybe 125, and to the tweeter at about 4kHz, IIRC. So this was really a pretty full range driver (from Philips, IIRC) with both low end and high end help. It needed hefty amps to start playing reasonably (wasn't much on a receiver with 40w RMS/chan), but across several of our stores, it was the speaker folkls tended to have on when they had free choice of what to listen to (ie, no customers, nothing to interfere with listening to something, ...).

I lived with a pair of Klipschorns for a while about then (don't know the model, but they were purchased new about 1971). They were driven by a high end Marantz transistor amp (model ?) from a Marantz tube tuner (the famous one whose model I can't recall), and an AR turntable (Shure top of the line cartridge). The horns' owner liked opera, so we got to listen to a lot of it. I remembe them to have been very low distortion, very clear, but not very sympathetic. A technical triumph, but not overly musical. Not quite horn-like (ie, sort of like a megaphone), but very distinctive and impossible to miss. Extradordinary bass, tight and 'quick', unlike the sealed box units from AR and KLH and ... Quite different than the Infinitys, but equally unsatisfactory.

One of the other fellows who lived there ended up with a pair of B&W DM2a. And that is the speaker I recall from that time as the best value for money. They were small enough to be practical, didn't cost a ton, didn't require whale amplifiers (though more RMS was noticeable and helped), but sounded absolutely extraordinary. They were clear, balanced, and didn't get in the way of the music. Not so good for high levels (it was a full-range woofer (6"?), crossed over to a tweeter about 3.5KHz, and to a supertweeter (a microphone element would you believe?) at something like 8kHz), and it wouldn't play loud either (small cone, limited xMax, and transmission line loaded -- this was soon after Bailey's 1st articles in Wireless World), but what it could handle was wonderfully done. No muddy bass, no cloudy midrange (vocals were excellent), very sharp (but far from painful) highs and so on. I never heard them with a Decca cartridge, but I wondered, then and still now, how they would have done. B&O made a conventional bookshelf speaker a few years later (model ?) which reminded me of the DM2a, but without even its basss performance. I got my brother a pair of those when he asked.

Other high end speakers from the time I can recall include the Rectilnear IIIa (huge multi-driver boxes), AR 3a, KLH 9 (ending their production run), and the largest Magnepan of the time. The Rectilinears had good bass, wide dynamic range before the onset of 'too much' distortion, and so on, but ultimately, the 10s were a better speaker, with all their limitations. The ARs were impressive, good low frequency, and midrange, but I never much liked their high end. And, being huge excursion woofers in a sealed box, they were somewhat sloppy sounding at low frequencies. Reflections from the box through the cone? or maybe inevitable in sealed boxes of the era? Most of the large acoustic suspension speakers from other suppliers (eg, KLH) had similar troubles. The KLH 9 had spectacular transparency, no WAF at all (7' tall, 3' wide, ...) Very little bass really, and they were hugely picky about the amps they would tolerate. When everything went well, and with good source material, they were very good. The best of the large panel speakers of the era that I ever heard were the Magnepans. We set them up in the shop to test them before they were sent out to the customers and the universal opinon was, 'pretty good'. I was one of the installation crew, and after we fiddled for about an hour, we found a good arrangement. The listening sweet spot was about 2' wide, and perhaps the smae deep, but when you were there, the sound snapped into precision and sweetness from 'pretty good' to exceptional. Not really good bass (bipole after all, even if there were clever compensations), but very very good. Sharp and clear and, like many good speakers (eg, Quads of the time, except for bass frequencies) the speakers disappeared. I concluded that if I had money to burn, I might consider them for a really high end system, but that they'd need a subwoofer (a la the Infinitys) and a lot of patience not to disturb the setup once it was discovered. We found that as little as 1/4" of orientatin change killed the sweet spot. Finicky as all get out.

I only heard the first Walsh driver models from Ohm a couple of times, but I was impressed by the openness (omnidirectional at all frequencies after all). Nice speakers, but very large, expensive, demanding of their amplifiers.

MacIntosh introduced its first speakers not long after this. Nobody I worked for carried them (very carriage trade sort of stuff), but I got curious enough to go find a dealer and (professional courtesy) got a good extended listen. Very impressive sounding, solid bass, evident highs, and so on. but they struck me very much as the Infinitys had. Flashy, and probably measured well, but not very musical to my ear. The Dahlquists were introduced about then as well. They were much less flashy, but more musical to my ear. Less intruding on the music. But, lightweight somehow. Not just missing thunderous bass lightweight, but something else. I would not have bought a pair had I the money.

If I thought some more, I suppose I'd have something more to say, but for the moement that's about it.