Aurex HR-710
¥ 7,900 (around 1975)
Commentary
This is a condenser type stereo headphone with reduced weight.
The semi-open type unit case eliminates the discomfort of being isolated from the outside while applying an appropriate load to the vibration unit in all bands. It uses ABS resin as the material and urethane foam as the sound-absorbing material.
The ear pad has a central raised shape with less energy loss, and it is an ear pad type instead of an ear cover type to eliminate the closed feeling.
The joint part with the headband has been simplified, and the head pad uses an air cushion type.
The head pad part is removable, so you can use it by putting it on your ear from your chin.
Uses back electret (back electrode electret) system.
In this method, since the diaphragm and the electret are separated, the efficiency of the electret itself can be increased. Moreover, by making the diaphragm thin, the vibration mass can be sufficiently reduced.
In the HR-710, a newly developed high-voltage electret (a special polymer film bonded to a metal plate) is electrically connected to the diaphragm through a high resistance, realizing stable operation of the diaphragm.
The diaphragm is made of polyester film with evaporated aluminum and has a diameter of 51 mm, a thickness of 4 microns and a mass of 11 mg.
Matching impedance can be switched by the Adapter part integrated with the plug.
3 positions can be selected for the matching impedance.
Stainless steel core wire is used for the cord part to realize thin yet strong wiring.
Model Rating
Type | Electret condenser headphone |
Headphone Section | |
Drive system | Push-pull full face drive |
Capacitance | 60pF |
Diaphragm | 4 micron thick polyester film diameter 51 mm Aluminum double-sided deposition |
Frequency characteristic | 20 Hz to 20 kHz |
Output sound pressure level | 95dB/3V (M position) |
Maximum sound pressure level | 115dB |
Harmonic distortion factor | 0.5% (at 400 Hz standard input) |
Ear pad pressure | 250g (Ear Spacing 150 mm) |
Code | 4-wire 2.5m with stereo plug Core Stainless Steel |
Weight | 160g (cord not included) |
<Adapter part> | |
Format | Input impedance switching type |
Input impedance | H (High) : 1k Ω M (Middle) : 300 Ω L (Low) : 8 Ω |