SOUND REFLECTION UNIT AND AUDIO LOUDSPEAKER UNIT COMPRISING SUCH A SOUND REFLECTION UNIT

Abstract: An audio loudspeaker unit incorporates a reflector, formed from a fired ceramic material. This reflector has a part (1) which defines a parabolic wall and a part (2) having an angled plane surface. The reflector is positioned with part (2) facing upwardly towards a "tweeter" high frequency range speaker (6), whilst the part (1) is directed towards a mid-frequency range speaker (5). A bass unit low frequency range speaker (7) is positioned in the base of the audio loudspeaker unit. If the bass unit (7) is to be omitted then the remaining parts (1, 2, 5 and 6) can be inverted. This disc type sound reflection unit provides omni-directional sound and the ceramic material provides a very true sound reflection.

Description: Sound reflection unit and an audio loudspeaker unit comprising such a sound reflection unit This invention relates to means for reflecting sounds produced in audio equipment in required directions. According to the present invention there is provided a sound reflection unit comprising a body formed from a ceramic material and being circular or tart- circular in plan view so as to define, in vertical cross- section, a parabolic surface extending in the one direc¬ tion, and an angieα plane surface extending in the other direction. In a preferred arrangement the body will define a complete disc in plan view; this then produces omni¬ directional reflection of sound from a loudspeaker directed onto the unit which can create a much better effect to a listener and this is enhanced where a pair of units are employed to create stereo sound. For certain purposes it may be desirable to direct the sound over an arc rather than over a complete circle. In this case the body will define a part- dircular portion merging into linear edge portions , in plan view. For ease _of manufacture the parts defining the two surfaces will be separately formed parts which have been secured together, back to back. The purpose of having two differently shaped surfaces for the body is that the parabolic surface is ideally suited for the distribution of sound created by mid-f equency and low frequency range speakers, whilst the angled plane surface is better suited for the distri¬ bution of -sound produced in the "high frequency range cf audio loudspeaker. _ According to a further aspect of the invention there is provided an audio loudspeaker unit comprising a sound reflection unit of this indention as hereinbefore defined, together wit a high frequency range speaker whose output is directed towards the angled plane surface, and a mid-frequency range speaker whose output is directed towards the parabolic surface. A low frequency range of speaker may be additionally positioned within the loudspeaker unit sc as to " have its output also directed towards the angled plane surface * . The invention may be performed in various v.-a s and preferred embodiments thereof will now be described with reference to the accompanying drawings, in which: Figures 1 and 2 comprise a plan view and a side view (partly in cross-section) of one preferred form of the sound reflectio _,unit of this invention, Figures 3 " and 4 comprise plan and side views of an alternative form of a sound reflection unit of this invention, and Figure 5 is a diagrammatic illustration of a - 3 - loudspeaker unit employing a sound reflector as illustrated in the earlier Figures. The reflector shown in Figures 1 and 2 is circular in plan view ' and is formed from two separate parts, 1 and 2, as can be seen in Figure 2. Both parts are formed from firing a ceramic material. It will be noted that the upper part 1 defines an outer wall of para¬ bolic form (as seen in cross-section) and has an enlarged rim 3 at the outer edge. This provides a recess for receipt of the rim of part 2 which is formed with an ang l e d plane surface (in cross-section) . After firing, the two parts are glued together to define the final sound reflector unit. A modified form of reflector is shown in Figures 3 and 4. In this instance the circular portion (in plan view) extends through only 180° and the unit then continues with linear edge portions 4. This type of unit is more suited for reflecting sounds in a preferential direction as there are no reflecting surfaces formed to the rear of . . the unit. The unit of a desired form . is incorporated into an audio louspeaker unit as shown in Figure 5. Here the reflector is positioned with the part 2 facing uσwardly towards a "tweeter" high frequency range speaker 6, whilst the part 1 is directed towards a mid-frequency range speaker 5. A bass unit low frequency range speaker 7 is positioned in the base of the audio loudspeaker unit. If the bass unit 7 is to be omitted then the remaining parts 1,2,5 and 6 can be inverted. The disc type sound reflection unit as shown in Figures 1 and 2 provides omni-directional sound reflection whilst the part disc shown in Figures 3 and 4 provides partial omni-directional sound reflection and a much greater sound field DercεDtion as comtiared with conventional shot sound, which is distributed over r, 0 O - from the centre of each loudspeaker cone. Public address systems are particularly suited for the provision of c ni-directional sound which will give far greater clarity in coverage and minimise the in-line or behind- speaker effect experienced with conventional sound distributors. The ceramic material from which the sound reflection units are constructed provides a very true sound reflection. The ceramic material used may include earthenware, stoneware, china, bone china, porcelain, sanitaryware and terra-cotta, fired at any conventional operating temperature. The deflection surfaces may be glazed or unglazed. The sound reflection unit shapes may be made by turning, slip casting, pressing, throwing or injection moulding in either solid or hollow form.

Claims: CLAIMS 1. A sound reflection urϊit Comprising a body formed from a ceramic material and being circular or part-circular in plan view so as to define, in vertical cross-section, a parabolic surface extending in the one direction, and an angled plane surface extending in the other direction. 2. A unit according to claim 1, wherein the body defines a complete disc in plan view. 3. A unit according to claim 1, wherein the body defines a part-circular portion merging into linear edge portions, in plan view. 4. A unit according to any one of claims 1 to 3 , wherein the parts defining the two surfaces are separately formed parts which have been secured together, back to back. 5. An audio loudspeaker unit comprising a sound reflection unit as claimed in any one of claims 1 to 4 , together with a high frequency range speaker whose output is directed towards the angled plane surface, and a mid- frequency range speaker whose output is directed towards .9 the parabolic surface." 6. A loudspeaker unit according to claim 5, wherein a low frequency range speaker is additionally positioned within the loudspeaker unit so as to have its output also directed towards the angled surface. 7. A sound reflection unit or an audio loudspeaker unit substantially as herein described with reference to the accompanying drawings.

Inventors: OAKLEY RALPH WILLIAM, PEARL ROGER GEORGE, OAKLEY, RALPH, WILLIAM, PEARL, ROGER, GEORGE
Applicants: OAKLEY RALPH WILLIAM, PEARL ROGER GEORGE, OAKLEY, RALPH, WILLIAM, PEARL, ROGER, GEORGE
Application year: 1989
Main classification: G10K11
IPC codes: G10K11, H04R1