Altec Lansing 403A (1968)

A 20 cm full-range speaker unit introduced in 1968, offering high cost-performance while preserving Altec’s characteristic tonal quality.

Overview

The Altec Lansing 403A is a 20 cm cone type full-range speaker unit released in 1968. It is recognized as a representative model among Altec's 20 cm full-range drivers, designed to deliver broad audio coverage with a single unit. The 403A was engineered for high-fidelity systems where simplicity and sonic coherence were prioritized. Multiple variations exist due to changes in materials and construction over its production period.

Specifications

Type	20 cm cone type full range speaker
Frequency characteristic	70 Hz to 11 kHz
Lowest resonance frequency	80Hz
Impedance	8 Ω
Rated input	12W
Output sound pressure level	102dB/W/m
Magnetic flux density	9,000gauss
External dimensions	Diameter 211x Depth 102 mm
Weight	1.35 kg (1970 catalog) / 1.4 kg (1976 catalog)

Design

The 403A originally used an Alnico magnet and featured a frame with a slit-shaped back. Around 1970, the frame slit design was modified. Later production shifted to a ferrite magnetic circuit. Early ferrite versions had a painted magnetic circuit with a model label on top; subsequent models removed the paint and updated the label. The cone, made of corn paper, also evolved during production, with corrugation added in later batches. These changes resulted in several identifiable variations of the 403A.

Reception

The 403A inherited the tonal character typical of Altec speakers while delivering high cost-performance, making it a practical choice for audiophiles seeking authentic Altec sound at a more accessible price point.