Audio Database


BETA series 20 cm double cone type full-range speaker unit.

The diaphragm is made of pulp, the main raw material, mixed with chemical fibers to reduce the unevenness of thickness and density seen in conventional speakers. In addition, carefully selected diaphragm is used in white color to avoid coloring.
Strong and high-density pulp is specially treated for the subcone for the high-frequency band.

The voice coil uses copper-coated aluminum wire that combines the advantages of copper and aluminum wires.

It uses Coral's unique skybar edge and star-shaped diffuser that expands directivity.

Uses a prominent frame and allows flat mounting on the baffle surface.

Model Rating
Type 20 cm Double Cone Type Full Range Unit
Nominal impedance 8 Ω
Program source input 16W (around the early 1970 s)
35W (around 1980)
Lowest resonance frequency 37Hz
Playback frequency band Fo ~ 20 kHz
Output sound pressure level 95dB/W/m
Magnetic flux density 15,500gauss
Effective vibration radius (a) 8.3cm
Equivalent mass of vibration system (mo) 8.5g
Qo 0.5
Mechanical crossover 6kHz
Maximum external dimensions Diameter 233x Depth 113 mm
Baffle Hole Dimensions 193mm
222 mm (when flat-mounted with prominent frame)
Mounting Hole Dimensions 180mm
208 mm (when flat-mounted with prominent frame)
Weight 3.3kg