Infinity IRS BETA

Pretty Sophisticated Speakers. Exciting, Best of Luck with them.

Many of you know I am a big fan of level controls to adjust output to the space.

excerpt from this review:

https://www.stereophile.com/floorloudspeakers/988infinity/index.html

"All the crossover filters for the EMI drivers are contained in the bases of the free-standing panels, as are the level controls for the three uppermost drivers. (The two LEMIMs are the only drivers without level controls, which is okay because all the others have them.) An electronic crossover (supplied) contains an active low-pass section, with response-contouring controls for the woofer towers, and a passive (straight-through) signal path for the upper-range panels. The Beta system must be bi-amplified, although it is unusual in that it feeds the full audio range to the upper-range amplifiers.

On the electronic crossover are a woofer level control, a crossover control—labeled "low-pass filter"—which changes the woofer low-pass turnover, a "high-pass filter" that establishes the system's LF cutoff frequency, a bass contour control (for rising, falling, or flat response below 40Hz), and a woofer polarity switch. On the rear of the crossover is a toggle switch labeled Open Loop Gain Comp, which is essentially a gain-compensating switch for the bass amplifier."

I wanted these speakers since they came out. Unfortunately, as a university student at the time, I could not afford to buy them. A few years later I bought a fine pair and connected them with an ML 32 preamp with phono and 2 Classe Omega Stereo (class A) amplifiers. My room size was about 700 sqf and 15 ft ceilings. I kept them for 10 years in my main system. A few notes from my experience:

1. Could sound a bit dry at times. However, this is function of multiple controllable parameters. Certainly best with excellent recordings.
2. Can it rock? It does well with ballads and softer rock, Its strong point is large classical works, jazz, world music and blues. It can play loud with caution.
3. Placement is very tricky. It took me long time to get the proper soundstage and timbres. Once done, lots of space between the instruments, depth and natural sound. The speakers totally disappear, even though they are massive. A large room is mandatory.
4. The foam around the bass units disintegrates over time. You should ensure the condition is good when you buy them. If replaced, it will take long time to break in again. In my case, they took over 6-7 months.
5. The sound improved a lot with a tube preamp. The CAT and Symphonic Line preamps were the best match I tried with the Classe amps (early 2000s).
6. The floor has to be solid. Otherwise, the sound will have significant deterioration. Some careful room treatment may be required. Need to try as you go for best results.
Overall, it is a great speaker system but its associated equipment must be truly high end to get the most out of them. Great dynamics and bass. Very difficult to get this level of performance today without spending $50K+ for a new pair of speakers.

Good luck. Enjoy them in good health. A rare find.

I’d love to have a set! With their age, be ready to replace a bunch of capacitors, speaker surrounds and whatever time has touched.

All the best!

I’ve worked my way up through the infinity line to my main system, which incorporates a late model IRS Beta system. My observations are room size / treatment, placement, amplification. Definitely a speaker that requires patience and quality components to bring out their best. If you like to tinker but demand results this system satisfies. Music genre is flexible, IMO a natural sound that will reveal poor recording’s. My amplifiers rare but (I think) complementary with relentless clean power are two Yamaha Pc5002m’s. With any necessary maintenance.. as with anything, this system will please. That with the rest involved will be with me for a very long time. Good luck if it works out and enjoy.

Cheers 

Check out my system page here. I've had a lot of fun with the Betas in recent years. I just let them go to fund other gear, but can't say enough good about them. Be prepared to invest considerable time getting them set up properly, not just placement but all the adjustments mentioned above. 

I tried many amps with the panels and the bass towers. Of all I tried, I think I liked the Bryston 7B monos as best performance/value, and McIntosh tubes up top. A pair of 275's running mono was very nice.

Enjoy!