Infinity Quantum 5 (Late 1970s)
A three-way loudspeaker system with EMIT tweeters and Polydome midrange drivers, known for high-fidelity sound.
Overview
The Infinity Quantum 5 is a vintage loudspeaker system introduced in the late 1970s by Infinity. It is a three-way design with a 12” Watkins woofer, an EMIT (Electromagnetic Induction Tweeter), and a Polydome midrange driver. The enclosure is well damped and finished in quality wood veneers to minimize resonance and keep the sound accurate. It was engineered for low distortion and high efficiency, and it handles detailed, dynamic audio across a wide range of genres.
Design
The Quantum 5 uses a three-way driver layout with a dual-drive woofer setup and an active crossover to keep the drivers in phase alignment. The cabinet is solidly built with high-quality wood veneers, and the drivers sit in a well-damped enclosure to cut unwanted resonance. The woofer section uses 700μF capacitors. The EMIT tweeter and Polydome midrange are both designed for extended high-frequency response and clarity.
Context
Introduced in the late 1970s, the Quantum 5 quickly gained a reputation for accurate sound and solid construction. Audiophiles knew it for crisp highs and punchy bass, and some users noted it could handle demanding audio with ease.
Market
Current asking prices for the Infinity Quantum 5 range from $360 to $700, depending on condition. Common problems are deteriorating foam surrounds on the woofers, failed EMIT tweeters, degraded crossover components such as capacitors, and loose or corroded wiring. Replacement parts, including 12” Watkins woofers and EMIT tweeters, are occasionally available on the secondary market.
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.