Infinity PRELUDE-MTS-CENTER: The Centerpiece of a Classic System

Name: Infinity PRELUDE-MTS-CENTER
Brand: Infinity

In the late 1980s, as home audio began its transition from pure stereo listening to full-fledged surround sound experiences, Infinity stepped forward with one of the most cohesive and sonically refined speaker systems of the era: the Prelude MTS (Matching Theater System). At the heart of this system—both physically and philosophically—was the Infinity PRELUDE-MTS-CENTER, a dedicated center-channel speaker engineered to anchor dialogue, vocals, and on-screen action with the same sonic precision as its satellite siblings. Though often overshadowed by larger floor-standing models, the PRELUDE-MTS-CENTER played a pivotal role in defining what a high-performance, integrated home theater system could be during a formative period in audio history.

Historical Context: The Rise of the Matching Theater System

Infinity, founded in 1968 by audio pioneers Cary Christie and Arnold Nudell, built its reputation on innovation—most notably the EMIT (Electro-Magnetic Induction Tweeter) and servo-controlled subwoofers. By the mid-1980s, the company had refined its approach to speaker design with the introduction of the Prelude series, a line of compact, high-sensitivity speakers that delivered surprising dynamics and clarity for their size.

The Prelude MTS was not just a collection of speakers; it was a complete audio ecosystem. Marketed as a “Matching Theater System,” every component—from the bookshelf satellites to the center channel and subwoofer—was voiced to blend seamlessly. The PRELUDE-MTS-CENTER was specifically designed to match the tonal character of the Prelude MTS satellites, ensuring consistent timbre across the front soundstage. This was critical for realistic dialogue reproduction and cohesive imaging, especially as consumers began adopting stereo and early surround formats like Dolby Pro Logic.

Released around 1988, the PRELUDE-MTS-CENTER arrived at a time when most “home theaters” were cobbled together from mismatched components. Infinity’s holistic approach stood out, offering audiophile-grade coherence in an era when convenience often trumped fidelity.

Technical Specifications

Specification	Detail
Model	PRELUDE-MTS-CENTER
Type	Passive Center-Channel Speaker
Driver Configuration	2x 3.5" woofers, 1x 1" EMIT tweeter
Frequency Response	80 Hz – 20 kHz (±3 dB)
Impedance	8 ohms (nominal)
Sensitivity	89 dB (2.83V/1m)
Crossover Frequency	~3.5 kHz
Enclosure Type	Sealed (acoustic suspension)
Dimensions (H×W×D)	6.5" × 16" × 7"
Weight	8 lbs (3.6 kg)
Grille	Magnetic, fabric-covered
Mounting Options	Keyhole slot for wall mounting
Recommended Placement	Horizontal, above/below TV

The PRELUDE-MTS-CENTER features a dual 3.5-inch mid-woofers flanking a central EMIT (Electro-Magnetic Induction Tweeter). The EMIT tweeter was a hallmark of Infinity’s design philosophy—offering extended high-frequency response with lower distortion than traditional dome tweeters of the time. Unlike conventional tweeters that use a voice coil and magnet, the EMIT employs a thin conductive foil suspended in a magnetic field, driven electromagnetically. This design reduces mass and inertia, resulting in faster transient response and smoother highs.

The sealed enclosure ensures tight, controlled bass response, while the horizontal cabinet is optimized for placement above or below a television—common setups in the pre-flat-panel era. With an 8-ohm impedance and 89 dB sensitivity, the speaker is relatively easy to drive, making it compatible with a wide range of vintage receivers and integrated amplifiers.

Sound Characteristics and Performance

The PRELUDE-MTS-CENTER excels in vocal clarity and tonal consistency. Its primary mission—anchoring dialogue in film and television—is fulfilled with remarkable precision. Voices sound natural and present, never harsh or recessed, thanks to the smooth integration between the EMIT tweeter and the midrange drivers.

Because it was designed to match the Prelude MTS satellites, the center channel ensures a seamless soundstage. When used in a full MTS setup, dialogue appears to emanate directly from the screen, with no timbral shifts as sound moves from left to center to right. This coherence was rare in its time and remains impressive even by today’s standards.

While the speaker rolls off below 80 Hz, it was intended to be paired with the Prelude MTS subwoofer (typically the powered SW-10 or SW-12), which handled bass duties and allowed the satellites and center channel to focus on midrange and treble. This division of labor resulted in a clean, dynamic sound without strain.

Notable Features and Innovations

EMIT Tweeter Technology: The standout feature of the PRELUDE-MTS-CENTER is its EMIT tweeter, a proprietary Infinity design that offered extended high-frequency response with minimal distortion. It gave the speaker a crisp, detailed top end without the brittleness sometimes associated with early high-efficiency tweeters.

Timbre-Matched Design: Every driver in the MTS system was voiced to match, ensuring that no single speaker stood out tonally. This was a significant advantage for home theater, where inconsistent timbre can break immersion.

Compact, Low-Profile Cabinet: The horizontal design allowed for discreet placement, and the magnetic grille provided a clean aesthetic. The cabinet was typically finished in a textured black vinyl wrap, consistent with the rest of the Prelude line.

Keyhole Mounting: Simple wall-mounting options made it easy to position the speaker optimally for dialogue clarity, whether on a stand or mounted near a CRT television.

Common Issues and Maintenance

Like all vintage audio gear, the PRELUDE-MTS-CENTER may require attention after decades of use:

Aging Foam Surrounds: The 3.5" woofers use foam surrounds that can dry out and disintegrate over time, leading to distorted bass or rattling. Re-foaming is a common and cost-effective restoration.

EMIT Tweeter Degradation: While robust, the EMIT tweeter’s conductive foil can degrade if exposed to moisture or physical damage. Some users report a loss of high-frequency output over time, though replacements or repairs are possible through specialty audio shops.

Crossover Components: The internal crossover may suffer from aging capacitors, which can affect tonal balance. A recapping by a qualified technician can restore original performance.

Grille and Finish: The vinyl finish may peel or crack with age. While not affecting sound, cosmetic restoration can enhance resale value.

Regular cleaning and avoiding high humidity environments will help preserve these speakers for years to come.

Current Market Value and Collectibility

The Infinity PRELUDE-MTS-CENTER is not a high-profile collector’s item like some vintage electrostats or horn speakers, but it holds a loyal following among enthusiasts of 1980s audio and home theater historians. In working condition, it typically sells for $50–$100 on the secondary market, often as part of a complete Prelude MTS system.

Its value increases when paired with matching satellites and subwoofer, as complete MTS setups are increasingly rare. Audiophiles restoring period-correct systems or seeking the unique EMIT sound often seek out these speakers for their coherence and vintage charm.

Conclusion: A Legacy of Coherence and Clarity

The Infinity PRELUDE-MTS-CENTER may not be the most powerful or flashy speaker ever made, but it represents a milestone in the evolution of home audio: the moment when high-fidelity engineering met the practical demands of home theater. Designed not as an afterthought but as an integral part of a unified system, it delivered what many center channels still struggle with today—natural dialogue, seamless blending, and musical integrity.

For vintage audio enthusiasts, restoring a Prelude MTS system with its original center channel is more than nostalgia—it’s a tribute to a time when companies like Infinity believed that every speaker in a system mattered. The PRELUDE-MTS-CENTER may have been built to sit in the middle, but its impact on the history of home audio is anything but marginal.