FIELD OF THE INVENTION

The present invention relates to a device for acoustic beam formation system and method thereof.

BACKGROUND OF THE INVENTION

It has been seen that there are many proposals in the past regarding the subject of sound enforcement at desired location to alarm or deter intruders by applying different type of drivers and waveguides. Many types of waveguides have been proposed to achieve the purpose and line array is one such technology which is employed for the formation of directed acoustic
beam at large distances and with high sound pressure levels. The line arrays are equipped with different types of waveguides along with acoustic to achieve this purpose and are employed in theaters and concerts. The sizes of the present line arrays systems are bulky and large in size. Proposal regarding other type of ultrasonic sound reinforcement systems exists with different arrangements in which the sound is projected through high frequency ultrasonic carrier waves. The ultrasonic systems has limitations in respect of its reach and intelligent-ability of speech as the high frequency ultrasonic waves suffers distortions due to the non linear nature of the air in with the waves propagate.

US4348750  Energy control device . Shows a device to focus sound at one point  atop 18  the frusto-conical reflector and second reflector 37  near the apex of the conical reflective surface thereof is at or proximate the focal point of the concave reflective surface of the parabolic reflector 38. The device is concentrating sound waves emanating from plurality drivers 36  to a single point and couldn’t travel at far locations to convey sound with high sound pressure levels.

US5526456  Multiple-driver single horn loud speaker system  teaches the method of attaching the multiple speakers to a waveguide but the arrangement is not compact and has limited potential to form a beam of sound because of the arrangement of the speakers and thus it cannot convey high sound pressure levels at far-off locations.

US4923031  High output loudspeaker system  In Fig1 of the respective patent drawing it shows two speaker units 12 and 13  facing each other with a wedge 30  in between to reflect the sound through its faces 32 and 34  forming a 45degrees reflector. However the wave front that emanate from the speakers is not a directional wave front  instead it’s a spherical wave front. The faces 32 and 34  forming a 45degrees reflector will not merge this wave front and instead it will cause multiple reflections. Thereby resulting into an omni directional sound output and hence beam formation of sound with such an arrangement is not possible.

US5898138  Loudspeaker having horn loaded driver and vent  teaches an arrangement of two speakers to direct sound. The Fig 1  of the said patent  it shows acoustic 16 and 18  inclined towards each other at a suitable angle. With walls 14A and 14B  forming a horn flare to project sound; however the wave fronts emanating from 16 and 18  will not combine and instead it will disperse like an omni directional wave-front. Therefore this system is not capable of forming sound beams and is unable to project high acoustic levels directionally.

The problem to be addressed is by the development of a system which could generate a beam of sound and create high sound pressure levels at its projection axis by employing the principles of constructive coherence and yet being light weight  and compact for mobile applications. This is done by modifying the acoustic wave front with different arrangements as it emanates from the plurality acoustic through waveguides and digital signal conditioning  such that the resulting wave front is coherently combined in a directional and controlled manner. This makes the present invention deliver higher sound pressure levels directionally at desired far locations and yet being light weight for mobile applications.

The invention relates more particularly to acoustic drivers but by no way of limitations to other radiating drivers  such apparatus and method.

OBJECTS OF THE INVENTION

It is  therefore  an object of the invention to provide a system capable of forming a beam of sound in a directional and controlled manner by disposing acoustic transducer in two line arrays with their horns facing towards the axis of projection. A parabolic reflecting surface is disposed on the top of the each line arrays of the acoustic drivers  which makes the emanating spherical wave front from the drivers into directional wave front. The parabolic reflectors are so aligned that the resultant emanating directional wave front from the acoustic transducer line arrays is diverted towards its center. The central portion of the two line arrays is disposed with a long reflector  having appropriate angle with respect to directional wave front emanating from each line arrays. The arrangement therefore combines and projects the directional wave fronts towards the projection axis and create tight beam of sound with high sound pressure levels (SPL).

It is another object of the invention to dispose plurality acoustic throats/exits parallel to the axis of radiation and thereafter convert it to directional wave front by providing a parabolic reflector on its top of the drivers  in such a manner that the omni directional wave front is made directional  by making the path lengths of the wave fronts equal.

It is another object of the invention to provide a long reflector at the center of the two line arrays  with length equal to the length of the line arrays and providing same reflecting angles on its both sides such that the to directional wave fronts are diverted towards the projection axis.

It is another object of the invention to provide a rectangular shaped waveguide with its sides forming hyperbolic profile and disposed on the top of the parabolic reflector  to further focus the wavelength effectively.

It is yet another object of the invention to provide a digital signal processor  to further acquire  digitize  compute and filter the acoustic signals and provide the final audio signal to the respective acoustic amplifiers.

It is yet another object of the invention to provide an audio signal from a microphone or sound player namely MP3  WAVE player etc.

It is yet another object of the invention to notify sounds and/ or intelligent verbal messages to warn or notify the intruders and with directional and high acoustic amplitude levels.

With the above and other objectives in view  as will hereinafter appear  various embodiments of the present invention are described hereunder.

SUMMARY OF THE INVENTION

According to an embodiment of the invention a device for acoustic beam formation system comprising: an arrangement of plurality acoustic disposed in a manner such that it forms two line arrays with their horns facing towards the projection axis; a parabolic reflecting surface is provided on the top of the each line arrays with its focus facing the throats/exits of acoustic drivers; thereby making the emanating spherical wave front from the drivers into directional wave front. The parabolic reflectors are arranged to divert the resultant directional wave front towards the center of each line arrays; a central reflector with two sloping sides and its apex pointing towards the projection axis  is disposed in the center and parallel to the line arrays. The two sloping angles are so provided to the flat central reflectors that these merge and divert the directional wave front parallel to the projection axis; thereby the system through the principles of constructive coherences between the wave fronts creates tight beam of directional sound and with high sound pressure levels (SPL). The system has a digital signal processor to acquire the audio signal and compute the required output acoustic signal; wherein the digital signal processor digitizes  computes and filter the input acoustic signal to the required output signal in accordance with the waveguide profile. It has acoustic amplifier to amplify the sound to the required level and provide it to the respective plurality acoustic .

According to another embodiment of the invention  plurality acoustic are disposed in a line arrays such that their throats faces parallel to the projection axis.

According to another embodiment of the invention  a combined or partitioned waveguide having an exponential flair is disposed at the throats of the plurality acoustic which form the line arrays.
According to another embodiment of the invention  a parabolic reflecting surface is provided on the top of the each line arrays with its focus facing the throats/exits of acoustic drivers thereby making the emanating spherical wave front from the drivers into directional wave front and is diverted towards each other.

According to another embodiment of the invention  a central reflector with two sloping sides and its apex pointing towards the projection axis is disposed in the center and parallel to the line arrays.

According to another embodiment of the invention  the two sloping angles of the central reflector merge and divert the directional wave front parallel to the projection axis;

According to another embodiment of the invention  outer reflector-A and outer reflector-B are disposed on the top of the conical waveguides of the two line arrays  with appropriate slopes and having exponential profile to focus the wave-front further.

According to another embodiment of the invention  a digital signal processor is provided  to acquire  digitize  compute  and filter the input acoustic signals and provide the final audio signal to the respective acoustic amplifiers.

According to another embodiment of the invention  an audio signal is provided through microphone or sound player namely MP3  WAVE player etc.

Brief Description of the Drawings

Figure 1 shows a detailed view of the waveguide according to the embodiment of the present invention.

Figure 2 shows a detailed view of the waveguide along with the projection details.

Figure 3 shows a detailed view of the embodiment of the present invention comprising elements to electrically drive the plurality acoustic drivers.

Figure 4 shows a detailed view of the waveguide as attached to the line array.

For better understanding of the embodiments of the invention and to show how it may be performed  it will now be described in more detail with reference to the accompanying drawings.

Detailed Description of the Invention

The present invention can be better understood by reading the following detailed description of some of the embodiments  with reference made to the accompanying drawings. It will be understood that a particular system embodying the invention is shown by way of illustration only and not as a limitation of invention. The principles and features of this invention may be employed in various numerous embodiments without departing from the scope of the invention. References are made to accompanying drawing in which its novel feature and advantages will be apparent.

As can be seen in Figure 1  it shows the embodiment of the present invention. The plurality Acoustic drivers 7  are placed adjacent to each other and arranged in such a way that their throats/exits faces parallel to the projection axis 1  and as a line array. This forms two different line arrays 13A and 13B arranged parallel to each other separated by a suitable distance. The two line arrays are provided with waveguides 12  on the throats of the plurality acoustic drivers 7  such that the energy gets projected efficiently. The line array 13A and 13B are disposed with identical parabolic reflectors 6  in such a manner that the focus of the parabolic reflector faces the throat of the plurality acoustic drivers 7  and the wave front is made directional and is further directed towards the center. The central location of the said line arrays is further disposed with a flat central reflector 8  parallel to the line arrays. The central reflector 8  comprise of two flat surfaces 14A and 14B  with its apex 8A  pointing towards the center of the projection axis 1  and towards the direction of wave propagation. The faces 14A and 14B  of the central reflector 8  forms identical slops with respect to the directional wave fronts falling of their surfaces  by their respective line arrays 13A and 13B  in such a way that the resultant wave front gets merged and becomes parallel to the projection axis 1. The planes 14A and 14B can be disposed with a movable hinge at its apex 8A  along with suitable means such that its angle with respect to the directional wave fronts could be adjusted as desired  to shape the resultant beam as diverging  merging or parallel with respect to the projection axis 1. The central reflector 8  thereby combines the two wave fronts emanating form two different sets of line arrays 13A and 13B together and diverts the generated acoustic energy parallel to the projection axis 1.

The arrangement is further disposed with two outer reflector-A 5  and outer reflector 4  to further project the acoustic wave fronts.

As can be seen in Figure 2  it shows the transverse section of the embodiment of the present invention along its length. The arrangement is shown to clarify the transfer functions being employed on the acoustic wave fronts. The plurality acoustic drivers 7  is disposed with a waveguide 12  to combine and project the waves towards the projection axis 1. The generated wave front is spherical in nature and spreads omni directionally. The top side of the plurality acoustic drivers 7  is further provided with a parabolic reflector 6  with its focus at or near the throat of plurality acoustic drivers 7. The parabolic profile 6  provides a transfer function to the spherical wave front in such a manner that their path lengths becomes equal; thereby making the wave front directional 3. The directional wave front 3  is directed towards the central reflector 8  which provides identical slopes with respect to the directional wave front 3  such that the resulting wave front gets combined with each other 2  and gets closer. The central reflector 8  thereby brings the two wave fronts closer which facilitates the formation of constructive coherence and directs the resultant wave front parallel towards the projection axis 1.

As can be seen in Figure 3  it shows the embodiment of the present invention with required elements. The audio input 9  is a sound input from microphone or any other audio player is applied to digital signal processor 10  which computes  analyzes and filters the input signal and transforms it appropriately with respect to its frequency content and its amplitude to match the profiles/dimensions of waveguide. It then sends the signal to the plurality acoustic amplifiers 11  to drive their respective plurality acoustic drivers 7.

As can be seen in Figure 4  it shows detailed design of primary waveguide 12  of the line arrays of the present invention. The plurality acoustic drivers 7  are arranged in a line and are disposed with a waveguide 12  having suitable slopes to combine and direct the omni directional wave front. The waveguide can be further divided into plurality partitions 12A along the entire length.

I Claim:
1. An acoustic beam formation system comprising:
A line array arrangement of the plurality acoustic drivers (7) with
their throats/exits facing towards the projection axis (1) and a
parabolic reflectors (6) disposed on the plurality acoustic drivers
(7) with its focus facing the throats/exits of the acoustic drivers (7);
wherein the omni directional sound emanating from the plurality
acoustic drivers (7) is made directional by equating their path
lengths; and a central reflector (8) to combine, reflect and project
the directional wave-front-A(3) parallel to the projection axis(1).
a digital signal processor(10) to acquire input audio signal(9) as
provided by MP3 or microphone; wherein
the digital signal processor acquire, digitize, compute, and filters
the input signals frequency domain, such that it becomes in
accordance with the shape and dimensions waveguide; and
driving the respective plurality acoustic amplifier(11) with their
respective plurality acoustic drivers (7); wherein
the emanating individual wave-fronts for the line arrays 13A and
13B, are combined through constructive coherence; thereby the
system is able to project the resultant acoustic waves in a
directional and in controlled manner.
13
2. The device as claimed in any of the preceding claims, wherein
the plurality acoustic drivers (7) are disposed in two different line array
with their throats parallel to the projection axis(1), along with their
respective primary waveguide (12) having slopes with exponential
profile.
3. The device as claimed in any of the preceding claims, wherein
the parabolic reflector(6) is disposed on the top of each line arrays
13A and 13B, with its focus facing the throats/exits of the plurality
acoustic drivers (7); thereby transforming the omni directional wave
front into a directional wave front(3) and diverting it towards the central
reflector(8).
4. The device as claimed in any of the preceding claims wherein,
a central reflector (8) is disposed parallel to the line arrays 13A and
13B, at their center and with its respective faces 14A and 14B forming
identical slopes with respect to the inwards traveling directional wave
fronts(3), in such a manner that the directional wave fronts (3) are
combined(2) and reflected parallel to the projection axis(1).
14
5. The device as claimed in any of the preceding claims wherein,
the two sides 14A and 14B of the central reflector (8) can be disposed
with a hinge at its apex (8A) such that the angle they form with respect
to the directional wave fronts (3) could be changed by adjusting the
gap between its base through appropriate means .
6. The device as claimed in any of the preceding claims wherein,
the outer reflector-A(5) has a slope of 10~40degrees with respect to
the projection axis(1) and outer reflector-B (4) bears an exponential
profile to focus the resultant wave-front parallel to the axis of
projection(1).
7. The device as claimed in any of the preceding claims, wherein
plurality of the device as per Figure 1, could be arranged contiguously
in a plane forming a matrix to further increase the sound pressure
level and directivity.
8. The device as claimed in any of the preceding claims, wherein
the acoustic alerts are notified by a tonal sounds and/ or verbal or
intelligent acoustic sound signal messages to warn or notify the
intruders.
15
9. The device as claimed in any of the preceding claims, wherein
the device can be use with other forms of radiating energies equally
well e.g. optical, microwave etc with reduced dimensions.
10. An acoustic beam formation system and method thereof
substantially as herein described and illustrated in figure 1, figure 2,
figure 3 and figure4 of the accompanied drawings.