Acoustics – Diaphragm and enclosure – Reflex baffle
Reexamination Certificate
1999-12-01
2001-10-09
Nappi, Robert E. (Department: 2837)
Acoustics
Diaphragm and enclosure
Reflex baffle
C181S149000, C181S160000, C181S199000, C296S078100, C280S288400
Reexamination Certificate
active
06298943
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a bass-reflex speaker, and more particularly relates to a bass-reflex speaker assembly that can be implemented in two-wheeled vehicles etc., vehicles that are used outdoors, and in other equipment.
2. Description of Related Art
Audio speaker systems where the phase of sound from a rear surface is inverted and the sound is outputted from a front surface are well known. This kind of speaker utilizes an acoustic effect where low-pitched sound resonates due to a hole formed at the front surface of a sealed speaker box and is referred to as a bass-reflex speaker. The resonant frequency is then determined by the size of the hole (port) and the length of a tube (resonant duct) attached to the port.
Ducts that project towards the outside of an enclosure (as in, for example, Utility Model Laid-open Publication No. Sho. 61-154092) are well known. Ducts that face towards the inside of an enclosure are suited to reproduction of low-pitched sounds, with resonant sound reflected at the rear surface of the enclosure being extracted from the duct. Ducts facing the outside function as a wall to prevent interference of high and low-pitched sound and are used to change frequency characteristics as a result of where such ducts are installed.
FIG. 8
is a view showing a duct that faces the inside of an enclosure and
FIG. 9
is a cross-sectional view of a duct that projects outwards from the enclosure. In both drawings, a speaker
32
is attached to a panel
31
of the enclosure, and a duct
33
is positioned below the speaker
32
. When a speaker system having this kind of configuration is mounted on a two-wheeled vehicle, etc., there are cases where water enters into the enclosure
30
from the duct
33
as a result of washing the vehicle or because of rain. Since water W temporarily entering the enclosure
30
accumulates at the bottom of the enclosure
30
, it has, in reality, been difficult to adopt such a speaker system in a two-wheeled vehicle.
Attention should be paid to the following when audio speakers are mounted on a two-wheeled vehicle having a cowling. When the vehicle is in motion the inside of the cowling is at negative pressure and air pressure differences occur at the paper cones of the speakers, i.e., at both sides of a diaphragm. The paper cones therefore deviate towards the rider side and the sound quality deteriorates. Having a bias current corresponding to the air pressure difference flow through the voice coil has been considered in order to resolve this problem (for example, Japanese Patent Laid-open No. Sho. 63-211899). However, the method for providing a bias current makes the system more complex, and a simpler method is therefore preferred.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a bass-reflex speaker system that resolves the aforementioned problems, that prevents water from leaking in and makes discharge of water straightforward when water has leaked in, that is appropriate for preventing deterioration of sound quality, and which can be installed in equipment used outdoors on two-wheeled vehicles, etc.
In order to achieve the aforementioned object, in a first feature of the of the present invention, there is provided an enclosure housing a speaker and defining an acoustic space and a resonant duct positioned at the front surface of the speaker at the lowermost end of the enclosure, wherein the resonant duct has an opening set in a designated direction within a range from a horizontal direction to a vertically downward direction at the front of the speaker. In addition to the first feature, in a second feature of the present invention, there is provided a speaker box covering the enclosure, the speaker box having a recessed surface formed at the front surface thereof so as to be inclined towards the rear, and the resonant duct protruding outwards from the recessed surface. Further, in a third feature of the present invention, the speaker box is formed of part of a motorcycle panel formed so as to cover the enclosure.
According to the first to third features, water that enters to within the enclosure is discharged to outside of the enclosure through the resonant duct which is provided improve the acoustic effect. In particular, according to the second feature, it is difficult for water falling from above, such as rain, etc., to enter the enclosure. According to the third feature, at the speaker box formed integrally with the panel of the motorcycle, water is prevented from entering to within the enclosure and discharge of water that does enter is possible.
In a fourth feature of the present invention, there is provided a bass-reflex speaker assembly mounted on a motorcycle having a front cowling, comprising: an enclosure, provided at a space covered by the front cowling, housing a speaker and defining an acoustic space and a resonant duct positioned at the front surface of the speaker at the lowermost end of the enclosure, wherein the resonant duct has an opening set in a designated direction within a range from a horizontal direction to a vertically downward direction at the front of the speaker.
In a fifth feature of the present invention, there is provided an air scoop having an air capturing opening, and a wind discharging outlet for discharging captured air to the rider, provided at the front of the vehicle. Furthermore, a louver is positioned facing the air scoop wind discharging outlet, with the resonant duct opening in a downward direction so as to point to between the wind discharging outlet and the louver.
According to the fourth and fifth features, when the inside of the cowling is at negative pressure due to wind while travelling, the inside of the enclosure also experiences a negative pressure via the resonant duct. Therefore, an air pressure difference does not occur at the front and back of the diaphragm of the speaker assembly installed within the cowling.
According to the fifth feature, the resonant duct points downwards and is hidden behind the louver. It is therefore not necessary to make space for positioning the resonant duct on the motorcycle panel, complicating the external appearance can be avoided and work can be carried out via the louver during maintenance.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 3828887 (1974-08-01), Alexander
patent: 4473251 (1984-09-01), Murayama
patent: 5012889 (1991-05-01), Rodgers
patent: 5109942 (1992-05-01), Akimori et al.
patent: 5197103 (1993-03-01), Hayakawa
patent: 5471019 (1995-11-01), Maire
patent: 5821471 (1998-10-01), McCuller
patent: 61-154092 U (1986-09-01), None
patent: 63-211899 (1988-09-01), None
Kanaoka Yoji
Nonaka Takehiro
Shimamura Koichi
Yamada Katsuhisa
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
Martin Edgardo San
Nappi Robert E.
LandOfFree
Bass-reflex speaker assembly does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bass-reflex speaker assembly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bass-reflex speaker assembly will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2570524