Infinity Modulus

A compact satellite speaker system paired with an active servo-controlled subwoofer, designed for high-fidelity music and home theater use.

Overview

The Infinity Modulus is a compact, efficient satellite speaker system designed for use in both stereo and home theater setups. It was part of a larger system that included a dedicated active subwoofer, the Infinity Modulus Sub Woofer, which was engineered specifically to complement the satellites. The system could be configured as a full surround setup with satellite speakers, a center channel, and the powered subwoofer. The main speakers feature a 2-way, airtight bookshelf design, while the subwoofer uses a 30 cm cone-type IMG woofer with a built-in 250W amplifier and servo control for low-frequency accuracy.

Specifications

Product type	2-Way, 2-Speaker, Airtight Type, Bookshelf Type
Units Used (Satellite)	For low band: 12.5 cm cone type; For High Frequency: Flat Type (EMIT)
Low-range driver (Satellite)	12.5 cm cone type IMG woofer with graphite-reinforced polypropylene diaphragm
High-frequency driver (Satellite)	EMIT tweeter with Kapton diaphragm, etched voice coil, neodymium magnet, push-pull magnetic circuit
Crossover network (Satellite)	4th-order 24dB/oct network with phase and distortion optimization
Front baffle (Satellite)	Step-like structure with high-loss foam to reduce diffraction
Enclosure (Satellite)	Hermetically sealed, two-layer structure of HDF and visco-elastic material, ~25 dB conduction loss
Exterior finish (Satellite)	Hard resin piano mirror finish
Speaker terminals (Satellite)	Gold-plated for bi-wiring
Bottom (Satellite)	Three directly connected isoparms with rubber cap and rigid plastic fittings
Product type (Subwoofer)	Active subwoofer
Units Used (Subwoofer)	30 cm cone type IMG woofer with graphite-reinforced polypropylene diaphragm
Amplifier output (Subwoofer)	250W
Attachment (Subwoofer)	Dedicated servo control amplifier
Servo system (Subwoofer)	Motional feedback detects diaphragm acceleration, compares with input signal, and applies negative feedback to reduce distortion and extend bandwidth by ~1 octave
Cutoff frequency (Subwoofer)	Switchable in two stages: 22 Hz and 35 Hz
External dimensions (Subwoofer)	Width 445x Height 475x Depth 445 mm
Weight (Subwoofer)	30.5kg
Optional accessories	Dedicated Stand Pedestal (620 mm height, 3.0 kg empty, 6.5 kg with sand, ¥34,000/set); Wall Mounting Brackets (¥34,000/set)
Original price (Subwoofer)	¥400,000 (1 unit, around 1990)
Original price (Satellite system)	¥220,000 (set of two, around 1990)

Design

The Modulus satellite speakers use a stepped front baffle to align the acoustic centers of the 12.5 cm IMG woofer and EMIT flat tweeter, reducing diffraction and improving time alignment. The enclosure is hermetically sealed with a dual-layer construction of ultra-high-density HDF and visco-elastic material, minimizing cabinet resonance. The EMIT tweeter features a Kapton diaphragm with an etched voice coil and a neodymium push-pull magnet system for low mass and high efficiency. The subwoofer incorporates a 30 cm IMG woofer with a built-in 250W amplifier and a servo control system that actively corrects diaphragm motion to reduce distortion and extend low-frequency response by approximately one octave. The system supports bi-wiring via gold-plated terminals, and optional sand-filled aluminum pedestals or wall brackets are available.

Context

The Infinity Modulus was designed as a high-detail compact speaker system, with the subwoofer sold separately to allow flexible system expansion. It was developed specifically to work in tandem with the Modulus Sub Woofer, forming a complete home theater or music playback system. The satellites were marketed as universal, compact, and efficient, suitable for both music and movie applications.