Like Infinity’s previous flagship loudspeakers, the goal of the formidable seven-feet, six-inches-tall, four-tower, Infinity Reference Standard (IRS), introduced in 1980, was to reduce “the musical distance between the live performance and its reproduced illusion.” Its sole design objective was to “achieve the world’s highest level of musical accuracy, and to develop the new technology needed to attain that objective.” Originally conceived as a statement of what a large line-source dipole without any design compromises could achieve, the IRS attained surprising commercial success, and served as HP’s long-time reference (and was ultimately replaced by Nudell’s own Genesis I loudspeaker system). That alone should be enough for the IRS to reach iconic status!
Each of its two woofer towers had six 12-inch polypropylene woofers and was driven by its own specially designed 1500 watts-per-channel servo amplifier. The servo woofer system combined a military-grade accelerometer with an instantaneous feedback loop to constrain the woofers to obey the corrected servo signal, thus lowering distortion and extending bass. Its two midrange/tweeter towers each contained 24 front-facing and 12 rear-facing EMITs, and 12 of Infinity’s new (at the time) midrange electro-magnetic induction drivers (EMIMs). The beautiful rosewood cabinet wings of the tweeter/midrange towers, custom-built by a shipbuilder, were precisely curved to minimize diffraction, sand-filled to dampen vibration, and required separate, user-supplied amplification. The system’s awesome frequency response was rated from 16Hz to 40kHz within plus or minus 2dB.
The IRS evolved throughout its history—most notably with driver improvements resulting in fewer colorations, greater transparency, and more clearly defined low-level details—and culminated in the IRS V (there was no IRS IV), which also included a 2000Wpc servo amplifier, among other enhancements. In its final iteration, this IRS achieved greater coherency thanks to a more seamless transition between its powerful bass drivers and nimble electromagnetic induction ones.
The IRS V was “a dream realized and a dream for this listener,” said HP, who praised its extraordinary soundstaging, lack of colorations, (what became known as) micro-and-macro-dynamics, and fine resolution.