Infinity IRS Beta

Infinity IRS Beta Speaker System- 1989 

2 Woofer Towers and 2 Midrange / Tweeter Panels, as well as, the Factory Manual:
History: One Owner, purchased new 1989
Physical Condition Excellent - Very Clean - No Grilles
Working Condition: Excellent- Checked by longtime Infinity Owner and Tech at 4/21

Paul McGowan, President of PS Audio, business partner and lifelong friend of world renown designer and founder of Infinity Arnie Nudell, writes:.
• The design is all planar magnetic (ribbon) down to approximately 100Hz. There, a servo driven woofer setup takes over-extending the bass response to 16Hz.
• Few systems today can equal their performance. These sounded so good, in fact, we received numerous 'best sound in show' awards from the magazines.
• In fact, Arnie preferred the IRS Betas for their mid-range musicality over the world renown IRS V!

Items Included and Miscellaneous Information:
• Servo cables
• IRS Beta Servo controller is included in original Box with Manual.


J Gordon Holt the former Editor of STEREOPHILE magazine used these as his speaker References for many years. I have read all the Reviews going back to pre-95 and these speakers were considered one of the three best speakers in the world.

    The Infinity "Beta" system is one of the great values in the used market. The system includes separate bass towers (6' high) with an electronic crossover (very versatile) and 2 large mid-range and treble panels.
    The system is extremely dynamic and transparent, with stupendous soundstage capabilities. Bass is awesome! A system that is not easily outperformed!

    The Beta uses a sophisticated form of servo control. One of the four woofers in each column has a high-quality accelerometer attached to its cone which measures the cone's changes in motional velocity. A second pair of (lightweight) wires carries the accelerometer output back to the crossover unit, and the signal is compared with the input signal, the difference being applied out-of-phase to the signal to correct for the discrepancy. (The woofers are said to be closely enough matched that the behavior of one will be typical of all.)

Technical Manual IRS BETA
• Woofers: Four 12” Polypropylene/Graphite Per Tower /Channel
• Mid Bass: 2 L-EMIMs — Midrange:
• 1 EMIM — Tweeters:
• 1 EMIM/front 1 EMIT/rear —
• Super-Tweeters: 1 SEMIT —
• Nominal Impedance: 4 Ohms
• Finish: Beautiful African Mahogany cabinets

Dimensions:
• (W x D x H) - Woofer module: 16 1/2” x 14 1/2” x 64 3/4”
• Mid/tweeter module: 17” x 1” x 64 3/4”
• Base footprint: 18” x 17”
Weight:
• Woofer module: 140 lbs
• Mid/tweeter module: 75 lbs
Total 430 lbs plus packaging

Other Information
• Bass Amplifier Requirements: 150-500 watts / ch
• Production History • Introduced in 1987 and Discontinued in 1992
• Original Retail Price: $11,950.00