Infinity Modulus
A compact satellite speaker system paired with an active servo-controlled subwoofer, built for high-fidelity music and home theater.
Overview
The Infinity Modulus is a compact, efficient satellite speaker system for both stereo and home theater setups. It was part of a larger system that included a dedicated active subwoofer, the Infinity Modulus Sub Woofer, engineered to go with the satellites. The full surround version used satellite speakers, a center channel and the powered subwoofer. The main speakers are a 2-way, airtight bookshelf design. The subwoofer uses a 30 cm cone-type IMG woofer, 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 satellites use a stepped front baffle. It lines up the acoustic centers of the 12.5 cm IMG woofer and the EMIT flat tweeter, which reduces diffraction and improves time alignment. The enclosure is hermetically sealed and built from two layers, ultra-high-density HDF and visco-elastic material, to keep cabinet resonance down. The EMIT tweeter has a Kapton diaphragm with an etched voice coil and a neodymium push-pull magnet system, giving low mass and high efficiency. The subwoofer has a 30 cm IMG woofer, a built-in 250W amplifier and a servo control system. The servo actively corrects diaphragm motion to reduce distortion and extend low-frequency response by approximately one octave. The system supports bi-wiring through 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. The subwoofer was sold separately, so buyers could expand the system as they liked. The satellites were developed to work together with the Modulus Sub Woofer as a complete home theater or music playback system. They were marketed as universal, compact and efficient, and suited to both music and movies.
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