Altec Lansing Milestone 604
A high-efficiency bookshelf speaker system using a coaxial 38 cm driver and manta ray horn for precise two-way sound reproduction.
Overview
The Altec Lansing Milestone 604 is a 2-way, bass reflex, bookshelf-type speaker system built around the 604-8K coaxial driver unit. Designed for high-fidelity audio playback, it features a large 38 cm cone woofer and a centrally mounted high-frequency horn driver. The system was priced at ¥560,000 per unit around 1997, indicating its position as a premium speaker in the Japanese market.
Specifications
| Unit | 38 cm coaxial type 2-way (604-8K) |
| Low band unit | 38 cm cone type |
| High pass unit | 2.5 cm Driver + Mantalehorn |
| Impedance | 8 Ω |
| Playback frequency band | 40 Hz to 20 kHz |
| Crossover frequency | 1.6kHz |
| Sound pressure level | 100dB SPL/W/m |
| Allowable input | 75W |
| External dimensions | Width 465x Height 905x Depth 505 mm |
| Weight | 55kg |
Design
The Milestone 604 uses the 604-8K coaxial unit, combining a 38 cm low-frequency cone made of high-quality corn paper with a horn-type high-frequency driver mounted through the center of the woofer. The high-frequency unit features a rigid aluminum alloy diaphragm, heat-resistant voice coil and bobbin, and a Tangerine Phase Plug. Its horn design departs from earlier multi-cellular types, instead using a manta ray Lehorn. The aluminum die-cast frame supports structural rigidity. The enclosure is a vented type with a 150-liter internal volume, constructed from 30 mm thick birch laminate with a teak veneer finish and a narrow baffle to reduce unwanted vibration. An M.F. level controller on the rear adjusts the crossover band around 1.6 kHz by up to ±10 dB without affecting the high-frequency unit’s output.
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