Infinity was a more "modern" speaker brand than KLH, Altec and Klipsch. They were pioneers in the utilization of new materials and driver types. Infinity was also highly esteemed by hi-fi enthusiasts, but had its share of problems. The company was established in 1968 by audiophiles Cary Christie, Arnold Nudell and Jack Ulrick. Their first product was a speaker combo consisting of 3-way electrostatics and integrated a subwoofer - the Infinity Servo-Statik.
While KLH already in the beginning of the seventies had attained a slim layer of "dust", and Altec brought out their rather conventional, but much improved, "Bookshelf Series" - Infinity was pressing on with their EMITs and EMIM's (Electro-Magnetic Induction Tweeter/Midrange) - and driver cones made in new, synthethic materials. The Infinity speakers we imported were all of the air-suspension types - that is with sealed cabinets. Also, their dividing networks tended to be on the complicated side. These facts reflected on the speakers efficiency. While KLH did not say much about this, but rather advised for careful use of the volume knob, Infinity recommended powerful amplifiers - and needed it, too. As such the brands harmonized well. Of course, Altec had both the efficiency and the power handling capacity.
Infinity had several series of speakers, the largest one being the RS-series. These speakers were rather special in that the tweeter and midrange section (EMITs and EMIMs) were mounted in a bi-directional section above an integrated bass cabinet with a greater physical depth. Shipped in light oak material these were rather elegant. I personally used a pair of RS 2.5 for a period, bi-amped by an Audio Research 52 in the mid/top - and a McIntosh MC225 taking care of the bass. And doing a good job at it!
Infinity also did some electronics, but on a small scale. One of their more successful products was the Black Widow tonearm. With it came a bottle of special viscosity oil that was meant to dampen the resonances of the arm/pick-up. I still have one of those - in an unopened box - with the oil bottle!
We weren't too unhappy to see Infinity go to another distributor. Their product range was rather unwieldy, with constant changes in drivers, materials and prices. Besides. Altec was much easier to sell. Infinity has since achieved a good standing in Norway and is presently very active in the Home Cinema field. Infinity is now part of the Harman International group.