Overview

The Coral Beta-8 represents a notable piece of audio history as an 8-inch double cone full-range speaker driver manufactured by Coral Audio Corporation during the 1970s-80s. The company, based in Tokyo, ceased operations in the mid-1980s but left behind a legacy of well-regarded speaker components. The Beta-8 features a pulp diaphragm reinforced with chemical fibers, copper-coated aluminum voice coil, and Coral’s unique “skybar” edge with a star-shaped diffuser/phase element to improve directivity. Two production versions existed: the early 1970s model rated at 16W and the later 1980s version handling 35W, both maintaining 8Ω impedance.

Scientific Validity

\[\Large \text{0.5}\]

Public manufacturer test data are limited and fragmented. Independent measurements by Rutcho provide Thiele–Small parameters and on/off-axis frequency-response with harmonic distortion plots (e.g., Fs≈42 Hz, Qts≈0.285, Vas≈46.8 L; measured sensitivity ≈94 dB/1 W/1 m). These are informative but not standardized across multiple samples or labs, and key metrics such as IMD under controlled protocols remain unavailable. Given the partial, non-standardized evidence base, the score remains at the 0.5 baseline while incorporating the available figures.

Technology Level

\[\Large \text{0.3}\]

The Beta-8 employed conventional 1970s–80s speaker technology including double-cone construction, chemical fiber–reinforced pulp diaphragm, and copper-coated aluminum voice coil design. While the star-shaped diffuser and skybar edge were proprietary for their era, the approach reflects analog–mechanical engineering without modern simulation-driven optimization or advanced materials. From today’s perspective, the implementation is readily reproducible using conventional methods.

Cost-Performance

\[\Large \text{1.0}\]

The Coral Beta-8 trades at approximately 77 USD on the vintage market. For a fair cross-class comparison against the least expensive generally available product that is not inferior in core function and measured performance, the Fostex FE206NV (8″ full-range, 8 Ω) is the current reference: it offers comparable or better published sensitivity (≈96 dB) and manufacturer-documented performance and retails around 149 USD. As the Beta-8’s going price is lower than this non-inferior baseline, the cost-performance score is maxed at 1.0.

Reliability & Support

\[\Large \text{0.0}\]

Coral Audio Corporation ceased operations in the mid-1980s. There is no official support, warranty, or parts supply, and users must rely on third-party specialists if service is required. Given the complete absence of manufacturer backing, the reliability/support score is the lowest tier.

Rationality of Design Philosophy

\[\Large \text{0.2}\]

The development approach reflects period-typical analog engineering without evidence of modern measurement-driven optimization. That said, current vintage pricing (~77 USD) can make the Beta-8 a practically rational choice for enthusiasts relative to modern full-range alternatives typically costing around 150 USD or more.

Advice

For vintage audio enthusiasts seeking authentic 1970s–80s aesthetics and sonics, the Coral Beta-8 offers historical significance and standout value at its current market price. Listeners prioritizing documented, modern performance, warranty, and ongoing support should consider paying more for contemporary units such as the Fostex FE206NV with official specifications and measurements.

References

[1] Audio-Database.com, “CORAL BETA-8 specifications”, https://audio-database.com/CORAL/unit/beta-8.html (accessed Sep 4, 2025)

[2] Rutcho.com, “Coral Beta 8 Fullrange Loudspeaker Measurements Data and Information”, https://rutcho.com/speaker_drivers/coral_beta_8/coral_beta_8.html (accessed Sep 4, 2025)

[3] DIYAudio Forum, “Why is nobody making a modern ‘Coral Beta 8’?”, https://www.diyaudio.com/community/threads/why-is-nobody-making-a-modern-coral-beta-8.191107/ (accessed Sep 4, 2025)

[4] Fostex, “FE206NV specification sheet (PDF)”, https://www.fostex.jp/wp/wp-content/uploads/FE206NV_specification_sheet.pdf (accessed Sep 5, 2025)

(2025.9.5)