OTOMON Laboratory　(音門ラボ)/Product details page

Extra rare Maxonic horn, manufactured in 70s year. Power supply use Tungar tube. Adjustable from 5V to 7V. It is one of Japanese product that has closest sound to Western Electric.

It was manufactured in 70s year and become one of Japanese honor, this is the best horn driver that has sound is very close to Western Electric, very very rare item and high reputation from audiophile. It is field coil driver, which use 7V power supply. Power supply use Tungar bulb tube, sound is very beautiful, clear and musical.

Specification:

The finest excitation type screwdriver designed for professional use such as theaters and large halls.
Each one is carefully made under strict quality standards.

The excitation type is adopted as this driver unit.
In a general speaker unit, it is ideal that the diaphragm behaves in the same way as the input signal current, but due to the weight of the diaphragm and voice coil, it does not operate immediately when an input is applied, and the current stops. However, the movement does not stop due to inertia and the sound is different from the original sound.
To eliminate this shortcoming, the excitation type unit creates a particularly strong magnetic field to speed up the start, and the voice coil produces a strong counter electromotive force to apply complete self-braking (electric braking).
The D51EX uses silicon steel, which has a magnetoresistance of one-thousandth of that of a ferrite magnet, to create a strong magnetic force and generate a counter electromotive force so that complete self-braking is applied.

Frequency characteristics 500Hz-18kHz
Output sound pressure level 108dB / m
Maximum allowable input 30W
Impedance 8Ω
Optimal crossover 500Hz or higher
Magnetic flux density 18,000 gauss
Excitation voltage 8V
Throat diameter 25mm
External dimensions Diameter 150φ x Depth 120mm
Weight 9kg
Sold separately: Excitation power supply for D51EX EX8-3 (¥ 8,000)
DC output voltage 6, 7, 8, 9V
Power supply voltage AC100V, 50Hz / 60Hz
External dimensions Width 120 x Height 90 x Depth 180 mm