Infinity RS-2001: The Forgotten Innovator in Bass Extension

In the early 1980s, home audio buyers wanted deeper, cleaner bass without the bulk of big floor-standing towers. Infinity Systems was working on that problem. The Infinity RS-2001 was one of its more unusual answers: a compact bookshelf-style speaker that used a passive radiator to get bass well beyond what its size suggests. It isn't as widely known as Infinity's larger models like the IRS series. It does give tight, articulate low end without a separate subwoofer.

A Brief Historical Context

The RS-2001 came out in 1982. Infinity, founded in 1968 by Arnie Nudell and Cary Christie, already had a reputation for boundary-pushing engineering, mostly from the IRS (Infinity Reference Standard) line, which used multiple drivers and complex crossovers to get full-range sound. The RS-2001 is more modest in scale, but it carries the same spirit of innovation.

The RS-2001 doesn't use a ported or sealed enclosure. It uses a passive radiator, a secondary diaphragm with no voice coil or magnet, to boost bass output. That gives more low-frequency extension and avoids the port noise and tuning limits of traditional bass reflex cabinets. Compact speakers of the day often gave up bass for size, and this one didn't.

Technical Specifications

Specification	Detail
Model	RS-2001
Manufacturer	Infinity Systems Corporation
Year Introduced	1982
Type	2-way, passive radiator bookshelf speaker
Driver Complement	1 x 6.5" woofer, 1 x 1" dome tweeter
Passive Radiator	1 x 6.5" (tuned to augment bass)
Crossover Frequency	~2,500 Hz (estimated)
Frequency Response	45 Hz – 20 kHz (±3 dB)
Nominal Impedance	8 ohms
Sensitivity	88 dB (2.83V/1m)
Recommended Amp Power	20–100 watts
Enclosure Type	Reflex-loaded with passive radiator
Dimensions (H×W×D)	14" × 8" × 9.5" (35.6 × 20.3 × 24.1 cm)
Weight	22 lbs (10 kg) per speaker
Finish Options	Black ash vinyl, walnut veneer

Sound Characteristics and Performance

The Infinity RS-2001 was built to punch above its weight. Despite its small footprint, it has a full-range sound, with bass that extends down to 45 Hz, a remarkable figure for a speaker this size in the early '80s. The passive radiator is tuned to resonate with the active woofer. It reinforces the low end without the chuffing or turbulence of ported designs.

The midrange is clean and neutral, typical of Infinity's design philosophy, which put accuracy ahead of coloration. The 1-inch soft dome tweeter gives smooth high-frequency response and avoids the harshness of some contemporary designs. It isn't as detailed as today's high-end tweeters, but it is well regarded for its natural tonal balance.

The RS-2001 does best in small to medium-sized rooms, with a balanced soundstage and good imaging. It pairs well with tube amplifiers for a warmer presentation or solid-state receivers for tighter bass control. Audiophiles have noted that placement matters. Sturdy stands and a slight toe-in let the speakers project a wide soundfield.

Notable Features and Innovations

The defining feature of the RS-2001 is its passive radiator system. A port can introduce wind noise and limit tuning precision. The passive radiator acts like a "drum head" that moves in response to internal air pressure. That allows deeper bass extension and faster transient response. Infinity had experimented with this technology in earlier models, but the RS-2001 brought it to a more accessible price point.

The other standout is the rigid MDF (medium-density fiberboard) cabinet, which was relatively advanced for its time. The enclosure is heavily braced to minimize resonance. The front baffle is cleanly finished and minimalist, with no visible screws or grilles in the original design (grilles were optional). The crossover uses high-quality components for the era, including polypropylene capacitors and air-core inductors, which contribute to a transparent sound.

The RS-2001 also reflects Infinity's time-aligned driver integration, a concept pioneered in their flagship models. It isn't executed as rigorously as in the IRS series. The tweeter is slightly recessed to align the acoustic centers of the drivers, which improves phase coherence and off-axis response.

Common Issues and Maintenance

Like any vintage speaker, the Infinity RS-2001 can suffer from age-related wear. The most common issues include:

Aging foam surrounds: The original foam on the woofer and passive radiator can dry out and disintegrate after 30+ years. This leads to distorted bass and reduced output. Fortunately, foam replacement kits are widely available and relatively easy to install with basic tools.
Tweeter degradation: While the soft dome tweeters are generally robust, exposure to high volumes or poor amplification can cause damage. Some users report a slight dulling of highs over time, which may be mitigated by cleaning the dome with isopropyl alcohol.
Crossover component drift: Capacitors in the crossover can lose capacitance over decades, altering frequency response. Replacing electrolytic capacitors and resistors can restore original performance.
Cabinet wear: The vinyl wrap on some models may peel, especially on edges. Walnut veneer versions tend to hold up better but can show scratches or water damage.

Regular maintenance, such as dusting, checking connections, and ensuring secure mounting, can extend the life of these speakers significantly. Given their solid build quality, many RS-2001s from the 1980s remain fully functional today with minor restoration.

Current Market Value and Collectibility

The Infinity RS-2001 is not a mainstream collector's item like the JBL L100 or Klipsch Heresy, but it has a dedicated following among vintage audio enthusiasts. In good working condition, a pair typically sells for $150 - $300 on the secondary market, depending on finish, condition, and whether they've been restored.

Fully restored units with new foam and upgraded crossovers can command higher prices, especially when paired with matching stands or original packaging. The walnut veneer models are slightly more desirable and may fetch a premium.

The RS-2001 isn't rare, but it is appreciated for its engineering ingenuity and balanced sonic signature. It suits listeners who want compact size without giving up bass, which makes it a good fit for vintage desktop setups, small listening rooms, or a retro hi-fi system.

Conclusion and Legacy

The RS-2001 may not have the star power of Infinity's flagship models. It puts passive radiator technology into a compact enclosure, giving deep bass and clarity in a format that fit comfortably in most living spaces.

Early experimentation with bass augmentation in small speakers like this one would later influence modern designs from brands like KEF, PSB, and even high-end computer audio systems.

A pair in good condition, or a pair that needs a foam rebuild, is the usual way to find an Infinity RS-2001.