The 1970's Infinity QLS 1...How would it compare?

How would a properly driven (worth a 500 page thesis in itself!) pair of these compare to $20,000 and under mainstays of today? These speakers have become an enigma to me...They were always two or three or a hundred and fifty steps beyond my grasp for different reasons and now they're getting hard to find and harder to find parts for so as to be forever relegated to the "one that got away" files. Anyone ever own these or otherwise spend any time with them? Closest I ever got to auditioning them was prob. late '78 at a Pacific Stereo (Unfortunately someone had underpowered them with one of the 80 lb. "monster recievers" of the day only hours before I got there so all I got was a look.) Ah, youth........
From what I vaguely remember of them they were the predecessor of the famous and great Servo Static 1-A electrostatic system. This was Arnie Nudell's first venture into electro magnetic drivers and getting away for stats. They one word...."ok". The mid's and high had some promise (later truly realized in his IRS, RS1-B's and Beta's). However, the bass (Arnie always had a bit of integration problems with the bass and mid's) were big, powerful but blotted.

Rick (RWD)
In a word: badly. The QLS had huge problems with a bloated mid-bass and integration with the much faster mid-range drivers. Run away from these. My experience is based upon a friend who owned them; he gave up after trying 6 months to make them sound right. I heard them many times in his room as we moved them around; tried different amps;different cables--all to no avail. The QLS came out after the SS-1As.
Ah youth.....

(If this link doesnt work, just search under Google images for Infinity QLS)

I also found my first pair of speakers on this site, the Infinity Qa.

I sold them to buy my first pair of Magneplanars and never looked back, but they were great at the time with my Technics SA 200 receiver and Sanyo TP 1020 turntable?!

I suspect you could do a lot better for the time and effort you would invest in an old pair of Infinitys.

But for sentimental value you could put them in a second system in a spare room with some cool 70's electronics and maybe a cassette deck.
it would be a sentimental journey only. tweeter to midrange to woofer integration as mentioned above was poor due to drivers used. also i never had a pair of speakers eat power the way those qls-1's did. the crossover was crude by today's standards and the cabinet while it was attractive was hardly rigid or inert. they were fun at the time but so were a lot of others things in my life that i would not want to go back to now. there are many other speakers from the 70's and older that have aged more gracefully.
I realize I'm digging up an old thread here, but I just wanted to state for the record that after a few days of work and a few hundred dollars worth of crossover rebuilding and new internal wiring, AND with these speakers being properly driven (which was clearly important to the OP and not addressed above) by a single 500Wpc Yamaha PC5002M amplifier (the pro version of the 101M), I believe you'd all find that the QLS1s are a truly fantastic speaker, certainly much better than what's been described above.

The only criticism I can still agree with is that there IS a little extra midbass, though it's not much. I haven't done a frequency response sweep to make sure my potentiometer settings are dialed in properly, so this may be the answer to that. If not, I'd bet that a judicious re-stuffing of the midbass coupler's transmission line should get rid of most of the issue. Oh, and the cabinet, though already braced, can indeed get a bit resonant with some loud bass hits below 35Hz or so. However, this is fairly simple to fix with a dowel rod and some DIY instructions, and I actually intend to do this in the next few weeks.

I guess that ultimately it depends on what exactly what you want out of a speaker, and how you rank these different wants. I would say that a rebuilt QLS1 does almost everything quite well, and some things even better than that. I have no experience with new >$2k speakers, so I can't speak to that part of the OP. Just don't expect the world out of a completely stock model, and be prepared to spend some dough on a serious amp.
I happen to own two pair, and have a large mound of serious ampolification (also old) to light them up. They are phenomenally inefficient, but worse than that, a extremely reactive. Take what you consider a decent amp (and skip the receivers) and the QLS will leave it straining both nuts to keep up. I have some rebuilt SAE amps which are good, and a Nakamichi PA-7 (the STASIS design) which is great. I biamp them using the built in biamp capability. The bass is powerful and solid (the PA-7) and the highs are fast and transparent. Also, the 48" column of tweeters has an extraordinary imaging trait. The soundstage does not move as you move up and down. It is like a "wall of sound", not a point of sound. The imaging is very good, but not so good as some more modern MTM designs.

With the QLSes, expect to spend some serious time auditioning amplifiers in your house with your speakers. Once dialed in, however, they are amazing speakers.

And you need a decent room to make them sing, also.
QLS-1s were not bad when they were new, but I had nothing but problems with them. I blew out a mid-bass coupler, then had CONSTANT problems with the EMITs, often spending more time fixing them, than listening.

Neat concept and imposing, but an overall disappointment
I have owned a pair of QLS1's for 30 years and I have never auditioned another system in any high end audio shop or in anyone's home that was even in the same league.Visitors to my home have initially commented the system didn't sound right to them until they listened to their own system later,then they cursed at me.The only problem with ever owning the QLS1's is that you will never be able to go back to the days when you enjoyed music from a typical stereo system.BTW, when i purchased these speakers i understood they required massive power amps, people that can't afford the amps will never truly hear what these speakers are capable of. Sincerely,Tony Barr
The reason drivers including the EMITs are blowen is due to under powered amplifiers. I have 8 pair of other speakers, but these sound more alive than others I tried. In the past I switched to other speakers such Magnapan Tympomies, Acoustats, AR 9As, but always returned to them. For components, I purchaced thre pairs and removed all usable components. I also am using a 600 watt per channel amp.
Ive owened them since 1982 I will likely sell them in the near future because I must down size.

I beg to differ with the tin eared post's listed above. The Infinity QLS1 was a trailblazer, and is still one of the finest speakers ever built. Almost every fault that people complain of with regards to these speakers occurs from them being under driven. Yes they are maybe the most power hungry speaker ever built, but if bi-amped and driven properly with 200 plus watts per side top and bottom, they have a sonic clarity, sound stage, breath and depth, seldom realized in sound reproduction. They were and continue to be awesome!
They used to sell them at Woodland Stereo back in the late 70's.  They also sold the Bedini/Sterloff amplifier and later various John Bedini amplifiers that worked very well with them.  The Bedini Gold amplifier was exceptional with them.  Al were 20 watts per channel, very noteworthy for the time.