Altec Lansing 620A Monitor (c. 1977)
A high-sensitivity coaxial bookshelf monitor using the 604-8G driver, built for studio-grade clarity and transient response.
Overview
The Altec Lansing 620A Monitor is a bookshelf-type speaker system for professional audio monitoring, marketed around 1977. It is a coaxial two-way design built around the 38 cm 604-8G driver, in a bass-reflex enclosure. It was built for high-fidelity reproduction with an emphasis on transient response and resolution, which suits complex acoustic environments where multiple audio channels overlap. The cabinet has a bright oak finish with a deep brown mesh grill on the back.
Specifications
| Model Rating Method | 2-Way, 1-Speaker, Bass Reflex System, Bookshelf Type |
| Units used | 38 cm Coaxial Type (604-8G) |
| Enclosure type | Bass-reflex enclosure |
| Impedance | 8 Ω |
| Frequency range | 20 Hz to 22 kHz |
| Output | 103dB |
| Allowable input (continuous program) | 45W |
| Crossover frequency | 1.5kHz |
| External dimensions | Width 660 x Height 1016 x Depth 457 mm |
| Weight | 62.6kg |
| Exterior finish | Bright oak finish |
| Grill | Deep brown mesh grill on the back |
Design
The 620A uses a coaxial two-way system built around the 604-8G, a 38 cm coaxial unit from Altec's 604 series. The high- and mid-frequency horn throat passes directly through the low-frequency magnetic circuit, which improves phase coherence. A specially designed multi-cellular horn aligns the sound image at the axis center, and the engineering focused on minimizing phase differences across the diaphragm. Compared to earlier models, the 604-8G has less vibration mass and keeps an alloy diaphragm with integrated edge, which improves wide-range and transient response. The enclosure is bass-reflex to extend low-frequency output.
Context
The Altec 620A is categorized among Altec Lansing low-frequency enclosures and is noted as a professional monitor speaker used in studio environments. Owners report it was built for clarity and high-quality sound reproduction, and that it excels in transient response. One user reported using up to five pairs before ultimately keeping none, which suggests its physical size and likely demanding setup and amplification requirements may have limited long-term practicality.
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