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PROBLEM TO BE SOLVED: To incorporate an acoustic lens of a concave shape for converting a
spherical wave generated by a headphone driver into an approximate plane wave.
Forward localization headphones
The present invention relates to a headphone which can obtain a realistic hearing without
discomfort by localizing a sound image in front of a listener.
With regard to the forward localization of headphones, much research has been done so far, and
the same time delay of right and left sounds as in the case of listening to the real sound has been
taken by binaural recording etc. It was not.
The results of many studies on the forward localization of headphones so far suggest that the ear
has a function to recognize the auditory distance other than the hearing that reaches the
tympanic membrane as the vibration of sound I have to.
As a means for causing the sound source to be recognized sufficiently forward, the sound wave is
assumed to be an approximate plane wave from the front giving vibration to almost the entire
In general, a headphone driver generates a spherical wave, which needs to be converted to a
sound close to a plane wave.
In order to solve this, the spherical wave from the headphone driver 1 of FIG. 1 is approximately
converted into a plane wave by the concave acoustic lens 2. By mounting the size in the
longitudinal direction in Fig. 2 as the size of the ear just in front of both the left and right ears,
the entire ear can be covered with a plane wave from the front, and the ear is recognized as a
sufficiently forward sound. can do. The sound other than the necessary direction is an obstacle to
the forward localization, and is absorbed by the sound absorbing material 3 covering the inside
of the case 4.
According to the present invention, a reliable forward localization can be obtained instead of the
in-head localization with the sense of incongruity as when listening to headphones so far. The
physical difference between the left and right sounds included at the time of stereo recording
includes the localization information before and after, so that the sound image of the space at the
time of recording can be reproduced.
It is a plane sectional view showing the internal structure of a headphone unit. It is a side
sectional view of a headphone unit.
1 ...... Driver unit, 2 ... Acoustic lens, 3 ... Sound absorbing material, 4 ... Case
The acoustic lens is a concave paraboloid to bring a spherical wave close to a plane wave, and is
arranged so that the virtual center of the headphone driver is at its focal point.
The sound from the front reaches the tympanic membrane by the reflection of the auricle and
the tragus, but the deterioration of the sound quality is suppressed by using a material having
the same physical characteristics as the acoustic lens.