Infinity RS-5: A Compact Classic from the Golden Age of Hi-Fi

In the late 1970s Infinity Systems was known for its ribbon and quasi-ribbon tweeters. The company also made more affordable models for the average audiophile. One of these was the Infinity RS-5, a compact bookshelf speaker introduced around 1979 for smaller listening rooms.

The RS-5 was never as celebrated as the IRS or EM series. It was a reliable, detailed-sounding speaker that punched above its weight in performance and build quality. Bookshelf speakers of the period were increasingly expected to deliver full-range sound without a separate subwoofer, and the RS-5 aimed for the usual Infinity traits: clarity, speed, and precision.

Technical Specifications

Specification	Detail
Model	RS-5
Manufacturer	Infinity Systems (US)
Year Introduced	1979
Type	2-way, passive bookshelf speaker
Driver Configuration	1 x 6.5" woofer, 1 x 1" dome tweeter
Frequency Response	55 Hz – 20 kHz (±3 dB)
Nominal Impedance	8 ohms
Sensitivity	88 dB (1W/1m)
Crossover Frequency	~3.5 kHz
Enclosure Type	Bass-reflex (rear-firing port)
Dimensions (H×W×D)	13" × 8" × 9.5" (33 × 20.3 × 24.1 cm)
Weight	17 lbs (7.7 kg) each
Recommended Amp Power	20–80 watts
Finish Options	Walnut vinyl veneer, black ash

The RS-5 featured a conventional but well-executed 2-way design. Its 6.5-inch woofer used a treated paper cone with a rubber surround, providing a balance of responsiveness and durability. The 1-inch soft dome tweeter—while not a true ribbon like those found in Infinity’s flagship models—delivered smooth, extended highs that avoided the harshness sometimes associated with early dome designs. The bass-reflex enclosure, with a rear-mounted port, helped extend low-frequency response, allowing the RS-5 to produce surprisingly full sound for a speaker of its size.

Sound Characteristics and Performance

The Infinity RS-5 was engineered for a balanced, detailed sound, suitable for both music and broadcast audio. Its strength was midrange clarity and transparent high frequencies. That made it a good fit for vocal-centric genres, acoustic recordings, and FM radio listening - popular uses in the late '70s and early '80s.

The soft dome tweeter gave a refined top end, free of the sibilance or "tizz" that plagued some contemporary designs. It wasn't as lightning-fast or airy as Infinity's ribbon tweeters, but it was natural and non-fatiguing over long listening sessions. The crossover sat at approximately 3.5 kHz and was well-integrated, with minimal overlap or phase issues between drivers.

The 6.5-inch woofer handled bass capably, reaching down to 55 Hz before it rolled off. In smaller rooms, or placed near walls or corners, the RS-5 could deliver a satisfying sense of weight and rhythm. Listeners who wanted deep bass or high SPLs would have needed to add a subwoofer or run the speakers bi-amped with external filtering.

Overall the RS-5 sounded clean and articulate. It was somewhat neutral, with a slight warmth in the lower mids that kept it from sounding clinical. It rewarded good source material and quality amplification, and did best with solid-state receivers or integrated amps with clean power delivery.

Notable Features and Design

The RS-5 didn't introduce any groundbreaking technology, but it reflected Infinity's focus on driver quality and cabinet construction. The MDF (medium-density fiberboard) enclosure was uncommon in budget speakers of the era. It gave a rigid, resonance-free platform that helped clarity. Internal bracing and dense damping materials helped minimize coloration.

The rear-firing port allowed flexible placement, though best performance needed some distance from the wall to prevent bass overhang. The front baffle was modestly styled, with a simple black grille (held by pins) that could be removed to reveal the drivers. The binding posts were basic, but they accepted bare wire and spade connectors, which was decent connectivity for the time.

One of the RS-5's quiet strengths was its compatibility. With an 8-ohm impedance and 88 dB sensitivity, it worked well with most mid-tier receivers of the era, such as those from Pioneer, Sony, and Yamaha. It was also a popular choice for early "compact system" setups, where performance and aesthetics both mattered.

Common Issues and Maintenance

Vintage RS-5 units are relatively rare today, but they turn up on online marketplaces and audio forums. As with any 40+ year-old speaker, aging components are the primary concern.

Tweeter degradation: While the soft dome tweeters were robust, some units may exhibit dried-out surrounds or oxidized voice coils. A hiss or distortion at high frequencies can indicate tweeter fatigue.
Woofer foam rot: The rubber surrounds on the woofer are prone to drying and crumbling over time. This is a common issue in vintage speakers and typically requires re-foaming or reconing.
Crossover capacitors: Electrolytic capacitors in the crossover network may have degraded, leading to muffled sound or imbalance between drivers. Replacing these with modern film capacitors can restore clarity.
Grille and finish wear: The vinyl veneer can peel or discolor, and the grilles may be missing or torn. Replacement parts are scarce, so original condition is a plus for collectors.

Because of Infinity's reputation, many of the drivers and crossover components are either still available or can be cross-referenced with modern equivalents. DIY restoration is feasible for anyone with basic speaker repair skills.

Current Market Value and Collectibility

The Infinity RS-5 is not a high-profile collector's item like the IRS V or the EM-3. It has a quiet appeal among vintage audio enthusiasts who like understated performers from the late 1970s. Well-maintained pairs in original condition typically sell for $150 - $300, depending on cosmetic state and whether they've been restored.

Its value lies more in usability than rarity. It suits a period-correct bedroom system or a retro living room setup, and it gives Infinity sound in a manageable footprint. It also appeals to buyers who want a neutral-sounding bookshelf speaker that doesn't dominate a room visually.

The RS-5 is not a flagship, but it is an important segment of Infinity's product line, one that brought high-quality engineering to a broader audience.

Conclusion and Legacy

The Infinity RS-5 may not have made headlines, but it combined thoughtful engineering, solid build quality, and a refined sonic character that belied its modest size and price point.

Even bookshelf models of the late 1970s were expected to deliver honest, engaging sound without compromise, and the RS-5 fits that expectation. It's a sleeper speaker that, with a little care, can still deliver a surprisingly modern listening experience.

A pair in good condition is worth maintaining. With proper maintenance, the Infinity RS-5 can still deliver the clarity that made the brand a legend.

Market Value

┌──────────────────────────────────────────────────────────────────────────┐
│ INFINITY RS-5                                                   Nov 2026 │
├──────────────────────────────────────────────────────────────────────────┤
│ High      $460                                    Latest            $460 │
│ Median    $240                                    Trend                — │
│ Low       $24                                     Volume           ~1/mo │
├──────────────────────────────────────────────────────────────────────────┤
│   $500 ┤                                                                 │
│        │                                                                .│
│        │                                                                 │
│   $286 ┤                                                                 │
│        │.                                                                │
│        │                                                                 │
│        │                                                                 │
│     $0 ┤                                               .                 │
│        ├─────────────────────────────────────────────────────────────────│
│    vol │█                                              █                █│
│        └─────────────────────────────────────────────────────────────────│
│         2026-02                      2026-04                      2026-05│
└──────────────────────────────────────────────────────────────────────────┘

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