Infinity KAPPA-90

Floorstanding 3-way speaker system with dual 10-inch woofers and EMIT-B tweeter.

Overview

The Infinity KAPPA-90 is a floor-type, 3-way, 4-speaker bass reflex system, also called a "Tall Boy" design. It has two 25.5 cm (10-inch) cone woofers for the lows, an 11.5 cm (4.5-inch) midrange driver, and an EMIT-B tweeter for the highs. That tweeter is the same model used in Infinity’s flagship IRS-Epsilon. The idea was to bring IRS technology into a more accessible package. The KAPPA-90 supports bi-wiring and includes cleats for secure speaker cable connections.

Specifications

Product type	floor-type speaker system, 3-Way, 4-Speaker, Bass Reflex System, Tall Boy Type
Units Used	For low band : 25.5 cm cone x2, For Medium Range : 11.5 cm Cone Type, For High Range : Special Type (EMIT-B)
Crossover	250 Hz, 3.5 kHz
Sensitivity	89dB/2.8V/1m
Input impedance	6 Ω
Nominal Impedance	6 Ω
Recommended amplifier output	30W ~ 300W
External dimensions	Width 390x Height 1,230x Depth 380 mm
Weight	40kg
Original price	¥ 190,000 (1 unit, around 1999)

Design

The two 25.5 cm woofers are APG Plus cones made with Kevlar and high-content carbon fiber. The 11.5 cm midrange driver has a non-magnetic magnesium chassis and a low-mass rubber suspension. The EMIT-B tweeter uses a lightweight etched voice coil, a waterproof stretch-resistant diaphragm, and neodymium magnets in a push-pull configuration. The crossover uses high-grade polypropylene capacitors, unsaturated P-core inductors, and metal film resistors. The cabinet is trapezoidal, built from high-density, low-resonance particleboard, and finished in oak. Black was available as a made-to-order option. Bi-wiring is supported.

Context

The EMIT-B tweeter in the KAPPA-90 is shared with the high-end IRS-Epsilon. That puts the Kappa series as a line that brings advanced Infinity IRS technology into a relatively more affordable form. The design emphasizes high fidelity and engineering quality from the flagship models, in a practical floorstanding format.

Market

Refurbished pairs of Infinity KAPPA-90 speakers were available for around €1000 as of mid-2023. Common maintenance includes replacing the foam surrounds and the capacitors. Aftermarket foam repair kits are available for the woofers.