Altec Lansing MK-4 (around 1991)

Name: Altec Lansing MK-4
Brand: Altec Lansing

A Japanese-market 2-way bass reflex speaker system designed for stage monitoring, featuring a manta ray constant directional horn.

Overview

The Altec Lansing MK-4 is a bookshelf-type, 2-way speaker system produced around 1991 as part of the MK series developed by ALTEC Sound Development (ASD), a brand established by Elektri to systematize Altec products for the Japanese market. Designed specifically as a bounce monitor speaker for stage use, it features a 38 cm cone woofer (ER-15) and a horn-loaded high-frequency unit (MR931-12 + 902-8B) with a manta ray Rhee Horn. The cabinet uses a bass reflex alignment based on Thiele & Small theory, constructed from plywood with a surface coating of FRP for durability.

Specifications

Product type	Speaker system, 2-way, 2-speaker, bass reflex, bookshelf type
Production period	around 1991
Design purpose	A bounce monitor speaker mounted on a stage
Woofer	38 cm cone type (ER-15)
High-frequency unit	Horn type (MR931-12 + 902-8B)
Horn type	MR 931 / 12 manta ray Rhee Horn, a constant directional horn
Frequency characteristic	50 Hz to 20 kHz
Impedance	8 Ω
Allowable input	65W
Output sound pressure level	103dB
Crossover frequency	1.5kHz
Maximum external dimensions	Width 690 x Height 483 x Depth 490 mm
Weight	27kg
Cabinet design	Bass reflex based on the Thiele & Small theory
Cabinet material	Plywood with FRP coating applied to the surface

Design

The MK-4 uses a 38 cm ER-15 cone woofer and a horn-type high-frequency unit comprising the MR931-12 manta ray Rhee Horn and 902-8B driver, forming a constant directional horn system that minimizes sound propagation on stage. The cabinet is built from plywood with a surface coating of FRP and employs a bass reflex alignment based on Thiele & Small parameters, optimized for accurate monitoring performance in live environments.

Context

The MK-4 is part of the MK series developed by ALTEC Sound Development (ASD), a brand created by Elektri to systematize Altec products for the Japanese market. This series represents a region-specific adaptation of Altec’s professional audio technology, tailored to local engineering standards and application needs.