GB2557980A

GB2557980A - A loudspeaker

Info

Publication number: GB2557980A
Application number: GB1621837.2A
Authority: GB
Inventors: Dahan Midbar
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-12-21
Filing date: 2016-12-21
Publication date: 2018-07-04
Anticipated expiration: 2036-12-21
Also published as: GB2557980B; GB201621837D0

Abstract

The loudspeaker comprises a housing 2 having a housing wall 11 which at least partially defines a horn-like void 13 having an opening 12. Sound from a drive unit 20 emerges from the opening 12. The housing wall 11 forms a portion of a Fibonacci spiral that extends from the drive unit 20 to the opening 12. The drive unit 20 is mounted within a smaller sub enclosure 14 such that the smaller loudspeaker may be used separately from the larger housing 2 (see fig 6).

Description

(54) Title of the Invention: A loudspeaker

Abstract Title: A loudspeaker comprising a detachable sub enclosure and a horn-like space shaped as a Fibonacci spiral (57) The loudspeaker comprises a housing 2 having a housing wall 11 which at least partially defines a horn-like void 13 having an opening 12. Sound from a drive unit 20 emerges from the opening 12.

The housing wall 11 forms a portion of a Fibonacci spiral that extends from the drive unit 20 to the opening 12.

The drive unit 20 is mounted within a smaller sub enclosure 14 such that the smaller loudspeaker may be used separately from the larger housing 2 (see fig 6).

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A LOUDSPEAKER

The invention relates to a loudspeaker, and especially an enclosure, housing or cabinet for a loudspeaker.

For many years attempts have been made to improve the quality of the sound reproduction of loudspeakers. Various shapes and configurations of loudspeaker enclosures have been proposed, some of which have been more successful than others.

In accordance with an aspect ofthe present invention, there is provided a loudspeaker comprising:

a housing comprising a housing wall at least partially defining a void having an opening;

an electroacoustic transducer adapted to be mounted to the housing; and wherein when the electroacoustic transducer is mounted to the housing, sound generated by the transducer is directed into the void, and the housing wall forms a portion of a Fibonacci spiral that extends from the electroacoustic transducer to the opening, so that the sound from the transducer is emitted from the housing through the 20 opening.

An advantage of the invention is that by the electroacoustic transducer directing the sound waves produced by the electroacoustic transducer into a void having a side wall defining a portion of a Fibonacci spiral, the quality of sound reproduction is improved.

Preferably, sound is emitted from the transducer in a direction that is substantially parallel to a first plane that is transverse to the housing wall forming the portion of the Fibonacci spiral, and preferably the first plane is substantially perpendicular to the housing wall.

Preferably, the separation between the housing wall and the enclosure wall increases from the transducer towards the opening. The void may be generally horn-shaped.

In one example of the invention, the transducer is mounted in an enclosure that is 10 removably mounted within the housing. In an alternative example of the invention, the transducer may be mounted in an enclosure that forms part of the housing or the transducer maybe directly mounted in or on the housing.

Typically, the housing wall is an external wall of the housing.

Preferably, the portion of the Fibonacci spiral is defined by a number of sequential terms in the Fibonacci series. Typically, three adjacent terms in the Fibonacci series are used to define the spiral to form the housing wall. Alternatively, it is possible that a different number of terms could be used, such as 4 terms, 5 terms or more than 5 terms.

More preferably, the spiral is defined by the 6^th to 8^th terms in the Fibonacci series. However, the spiral may be defined by any other part of the Fibonacci series, such as for example, the 3^rd to 5^th terms, 5^th to 7^th terms or 7^th to 10^th terms. Preferably, the terms of the Fibonacci series that are used to define the part of the Fibonacci spiral that forms the housing wall are less than or equal to the 10th term.

Typically, an enclosure wall of the enclosure of the transducer is at least partially curved and could be substantially semi-circular. However, preferably, the curve part of the curved enclosure wall is defined by a part of a Fibonacci spiral. More preferably, the curved part of the enclosure wall is defined by at least two terms of a Fibonacci spiral. Most preferably, the enclosure wall is defined by two terms of a Fibonacci spiral and a substantially straight wall portion. Preferably, the enclosure wall of the 10 transducer is transverse to the first plane and preferably, substantially perpendicular to the first plane. Typically, a plane defined by the enclosure wall and a plane defined by the housing wall are substantially parallel in a direction perpendicular to the first plane.

Typically, the cross-section of the void defined by the housing and enclosure has a polygonal cross-section and preferably, a rectangular or square cross-section. However, alternatively, the cross-section could be circular or elliptical.

Preferably the transducer forms part of an electrical circuit that may also include an 20 amplifier to amplify electrical signals received by the loudspeaker and the amplified electrical signals are output to the transducer. Typically, the amplifier may be a component of the electrical circuit and may be powered by one or more of a solar panel, a battery and an external power supply.

Typically, at least part of the electrical circuit is located in the enclosure.

The electrical circuit may include a power source, such as a battery, which may be rechargeable and may be located in the enclosure, and/or a solar panel. The battery is especially useful where the transducer and amplifier (if present) are mounted in an enclosure that is removable from the housing. This permits the transducer and enclosure to be used as a loudspeaker separate from the housing. Alternatively, or in addition, the electrical circuit may be powered by an external power source, such as a mains operated power source.

Preferably, the loudspeaker includes at least one Bluetooth® transceiving device coupled to the transducer to permit sound to be streamed wirelessly to the loudspeaker and/or to be streamed wirelessly from the loudspeaker to another loudspeaker, for example to create a stereo sound effect. Typically, the Bluetooth® transceiving device is located in the enclosure if the transducer is removable. Where there is an electrical circuit with an amplifier, the Bluetooth® transceiving device may be coupled to the transducer via the amplifier, so that signals received by the Bluetooth® transceiving device are amplified by the amplifier and then the amplified signals are output to the transducer. The loudspeaker may include two Bluetooth® transceiving devices to permit two Bluetooth® wireless connections to be established simultaneously with two other Bluetooth® enabled devices. For example, this would permit sound signals to be streamed wirelessly to the loudspeaker from a sound source and sound signals to be streamed from the loudspeaker to another loudspeaker to create a stereo sound effect simultaneously.

If the loudspeaker includes a solar panel, it may be mounted on an external surface of the housing. Alternatively, the solar panel could be mounted on the enclosure. In a further possible example there could be a solar panel on the enclosure and solar panel on the housing. The solar panel may be electrically coupled to an electrical circuit that drives the transducer and/or enables electrical energy from the solar panel to charge a rechargeable battery that forms a power source for the electrical circuit. In certain implementations the solar panel may be coupled to the electrical circuit to both drive the electrical circuit direct and to charge the rechargeable battery.

In one example, at least a part of the electrical circuit and the battery may be located in the enclosure. In another example a rechargeable battery and at least a part of the electrical circuit may be mounted on the housing so that electrical energy from the solar panel charges the rechargeable battery on the housing via the electrical circuit. The rechargeable battery on the housing may be used to supply power to the transducer 15 and/or to provide electrical power to an external device through an appropriate electrical connector, such as a power jack on the housing or a USB Type-C port on the housing. Alternatively, or in addition, the electrical connector may be used to charge the rechargeable battery.

Typically, the loudspeaker may also have an input device, such as a socket, coupled to the transducer, to permit an external electrical sound source, such as a sound playing device, to be electrically coupled to the speaker by means of a wire or cable. The sound playing device could be an mp3 player, a CD player or other sound source that outputs sound by an electrical signal.

The loudspeaker may also have an output device, such as a socket, to permit electrical sound signals to be output to another sound reproduction device, such as another loudspeaker to facilitate stereo sound reproduction.

Additionally, the loudspeaker may include an appropriate electrical connector, such as a power jack or a USB Type-C port, to enable power to be supplied to the loudspeaker from an external power supply to power the loudspeaker and/or to charge a rechargeable battery mounted within the loudspeaker. The electrical connector and/or rechargeable battery mounted within the loudspeaker may be in addition to the 10 electrical connector and/or rechargeable battery on the housing.

As an alternative to rechargeable batteries it is possible that the loudspeaker and/or the housing may be adapted to have non-rechargeable batteries mounted therein, which preferably may be replaceable by a user.

Preferably, the loudspeaker may comprise an electrical circuit to control the transducer. Typically, the electrical circuit may comprise an amplifier coupled to the transducer. The electrical circuit may be powered by any one or more of: (i) the solar panel on the housing; (ii) the rechargeable battery on the housing; (iii) the rechargeable 20 battery on the enclosure; and (iv) an external power supply.

Where the housing includes a solar panel and/or battery, and the enclosure with transducer is removable from the housing, the housing may include an electrical connector that engages with a complimentary electrical connector on the enclosure to enable electrical power to be transferred from the solar panel and/or battery on the housing to the enclosure to provide an electrical power source for the enclosure, for example to power the electrical circuit in the enclosure.

Preferably, the transducer is located at one end of the portion of the Fibonacci spiral and the opening is located at the other end.

An example of a loudspeaker in accordance with the invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a loudspeaker;

Fig. 2 is a plan view of the loudspeaker;

Fig. 3 is a side view of the loudspeaker;

Fig. 4 is a cross-sectional view of the loudspeaker with a transducer enclosure mounted in a housing;

Fig. 5 is a cross-sectional view of the housing of the loudspeaker without the transducer enclosure;

Fig. 6 is a perspective view of the transducer enclosure;

Figs. 7A and 7B are schematic diagrams of electrical circuits for use in the transducer enclosure and the housing, respectively; and 20 Figs 8 to 10 illustrate different sizes of Fibonacci spirals.

Figs 1 to 4 show a loudspeaker 1 which includes a housing 2 and a transducer enclosure 3. An electroacoustic transducer (or speaker) 20 (see Fig. 7A) that converts electrical signals into sound waves is mounted in the enclosure 3 behind a grill 17. The enclosure 3 also includes an electrical circuit 40. The electrical circuit is not visible in

Fig. 4 but is shown in detail in Fig. 7A.

The housing 2 includes a solar panel 4 mounted on one side of the housing 2, a rechargeable battery 35, an electrical circuit 36 mounted in a void 37 in a supporting flange 10. The solar panel 4 is shown as a single panel on one side of the housing 2.

However, the solar panel could be on two or more sides of the housing 2 and could be a complete side of the housing 2 or two complete sides of the housing 2. In another possible example, the entire housing could be formed from solar panels or the entire 10 external surface of the housing could be covered by solar panels.

The supporting flange 10 includes two spring-loaded male electrical contact pins 6 (only one shown) that engage with complimentary electrical contact plates 5 on the enclosure 3 (see Fig. 6). A schematic diagram of the electrical circuit 36 is shown in 15 Fig. 7B and comprises a battery management circuit 33, a USB charge control circuit and a protection circuit 34. The protection circuit 34 is coupled to the output from the solar panel 4 and protects the battery management circuit 33 by preventing current and/or voltage surges from the solar panel 4 damaging the battery management circuit

33. The USB charge control circuit 32 controls the current and voltage from an external power supply input at the USB-C port 31. The battery management circuit 33 controls the charging of the rechargeable battery 35 and receives electrical power to charge the battery 35 from the solar panel 4 via the protection circuit 34 and the USB-C port, when an external charging device is connected to the USB-C port. The battery management circuit 33 also controls the supply of electrical power to the enclosure 3 via the electrical connectors 6. In addition, the battery management circuit 33 can also control the supply of electrical power to the USB-C port 31 to power an external device connected to the port 31.

The transducer enclosure 3 may be removable from the housing 2 so that the transducer enclosure 3 may be used as a stand-alone speaker separate from the loudspeaker housing 2. The transducer enclosure 3 includes two electrical connectors that electrically couple with the two electrical connectors 6 when the enclosure is mounted in the housing against the support flange 10, as shown in Figs. 1 to 5, the two 10 electrical contact plates 5 engage with the ends of the spring-loaded male electrical contact pins 6 and depress the pins 6 into the flange 10 against the actions of the springs (not shown) that bias them to the position shown in Fig. 5. Hence, the pins 6 are biased into contact with the contact plates 5 to create an electrical connection between the pins 6 and the plates 5. When the enclosure 3 is removed from the 15 housing 2, the plates 5 disengage from the pins 6 allowing the springs to move the pins 6 back to the position shown in Fig. 5.

As an alternative to the pins 6 and plates 5, the electrical coupling between the circuits

36, 40 could be a wireless electrical coupling that does not require physical contacts.

The electrical circuit 40 also includes an input audio jack 8 and an output audio jack 9 mounted on the transducer enclosure 3, together with a USB-C port 7 also mounted on the enclosure 3. The audio jacks 8, 9 are typically 3.5mm audio jacks. The port 7 is primarily a power socket to enable an external power supply (not shown) to be connected to the circuit 40 to power the circuit 40. The audio jack 8 permits an external source of music to be connected via a wire or cable to the loudspeaker 1 to play music from the source through loudspeaker 1. The audio jack 9 permits an audio signal to be output from the loudspeaker by a cable to another loudspeaker to enable a stereo audio effect to be achieved.

Fig. 7A is a schematic diagram of the electrical circuit 40 within the transducer enclosure 3. These include an electroacoustic transducer 20 and amplifier 21, a rechargeable battery 22 and a Bluetooth® controller 23 coupled to an antenna 29. A microcontroller 24 controls overall operation of the electrical components of the circuit

40 and of circuit 36 when electrically coupled to the circuit 36. When the circuit 40 is not electrically coupled to the circuit 36, the solar panel 4 and/or an external power source (not shown) coupled to the USB-C port 31 can still be used to charge rechargeable battery 35 via the battery manager 33.

The circuit 40 also includes a battery manager 28 to manage the charging and power supply from the rechargeable battery 22, a USB charge control circuit 27 to control power received from an external power supply (not shown) coupled to the USB-C port 7. In addition, an analogue to digital converter 26, a digital to analogue converter 25 and a combined power on/off switch and LED 30 are coupled to the microcontroller 24.

The LED in the combined switch/LED 30 is a red/green/blue LED and the different colours of the LED can be used to indicate different features, such as whether the speaker is switched on or off, whether a Bluetooth® connection exists or whether the rechargeable batteries 22, 35 are fully charge or charging. The input to the ADC 26 is coupled to the audio jack 8 and the output from the DAC 25 is coupled to the audio jack 9 and to the transducer 20 via an amplifier 21.

The transducer enclosure 3 locates within the large speaker housing 2 by means of a frictional fit which holds the transducer enclosure 3 in place. The transducer enclosure is located by pushing it up against the support flange 10 located on the inside of the housing 2. When the enclosure 3 is pushed into position against the support flange 10, the electrical connectors 6 on the support flange 10 engage with the electrical connectors 5 on the enclosure 3 so that the electrical circuit 36 is electrically coupled to the electrical circuit 40. The transducer enclosure 3 also has a lip section 15 that locates over an end 18 of the support flange 10 and adjacent and end 16 of the wall 10 11, as shown in Fig. 1. The end 18 of the support flange 10 and the end 16 of the wall together form an L-shape.

The Fibonacci series is a number sequence where the n^th term is given by the formula: Xn = X(n-i) + X(n-2). Therefore, the first few terms of the Fibonacci series are as follows:

1,1,2,3,5,8,13,21,34,55,...

A Fibonacci spiral can be created by drawing adjoining squares each having a side length equal to the corresponding term of the Fibonacci series. Hence, the first square has side = 1, the second square has side = 1, the third square has side = 2, the fourth 20 square has a side length = 3, the fifth square has a side length = 5, etc. A Fibonacci spiral is then created by drawing circular arcs connecting the opposite corners of squares in the Fibonacci tiling. Different numbers of squares based on the Fibonacci series with the corresponding Fibonacci spiral drawn are shown in Figs. 8 to 10. Fig. 8 shows a Fibonacci spiral 50 for the first 8 terms of the Fibonacci series, Fig. 9 shows a Fibonacci spiral 60 for the first 9 terms of the Fibonacci series and Fig. 10 shows a

Fibonacci spiral 70 for the first 10 terms in the Fibonacci series. In each case the numbers inside each square indicate the value of the corresponding term of the Fibonacci series for that square and the side length of that square.

The housing 2 includes an external curved side wall 11 that is formed from part of a Fibonacci spiral, in this case the spiral shape is that defined by the 6^th to 8^th terms of the Fibonacci series, that is χβ = 8, χγ = 13 and xs = 21. However, as can be seen from

Figs. 8 to 10, as the Fibonacci spiral has a similar general recurring shape, irrespective of the terms of the Fibonacci series, other parts of the Fibonacci series could be used 10 to define the spiral, particularly the parts of the Fibonacci series less than or equal to the 10^th term. For example, the 3^rd to 5^th terms, 5^th to 7^th terms or 7^th to 10^th terms.

Typically, three adjacent terms in the Fibonacci series are used to form the wall 11, although it is possible that a different number of terms could be used, such as 4 terms, terms or more than 5 terms. Preferably, the terms of the Fibonacci series that are 15 used to define the part of the Fibonacci spiral that forms the wall 11 are less than or equal to the 10^th term due to changes in the shape of the spiral above the 10^th term that is due to changes in the ratio of adjacent terms above the 10^th term.

The transducer enclosure 3 is located at one end 16 of the wall 11 defining the 20 Fibonacci spiral, at the lowest term of series defining the part of the Fibonacci spiral.

At the other end of the wall 11, the part of the wall 11 formed by the spiral defined by the highest term is an opening 12 and a void 13 extends from the grill 17 of the transducer housing 3 adjacent the stop 10 from the transducer enclosure 3 around the inside of the wall 11 to the opening 12. A rear wall 14 of the transducer enclosure 3 is formed from a curved section 14a and a straight section 14b. The curved section 14a is preferably formed (or defined) by a portion of a Fibonacci spiral, typically a portion of a Fibonacci spiral defined by two terms of the Fibonacci series. Most preferably, the curved section 14a is formed from a portion of a Fibonacci spiral defined by the two terms immediately below the terms that the wall 11 is formed by. So for example, if the 5 wall 11 is from a portion of a Fibonacci spiral defined by the 5^th to 7^th terms, the curved wall 14a of the enclosure 3 is formed from a portion of a Fibonacci spiral defined by the 3^rd and 4^th terms. This provides a continuous Fibonacci spiral curve to the wall 11 and the curved wall 14a. Alternatively, the curved wall 14a could be formed by another surface such as a hemi-spherical surface. However, it has been found that improved 10 sound reproduction is obtained by forming the curved wall 14a also with a part of a

Fibonacci spiral and preferably, the part of the Fibonacci spiral defined by the terms of the Fibonacci series that are immediately below and adjacent to the lowest term from which the wall 11 is formed.

The use of a curved wall 14a has the effect of causing the void 13 to increase in size towards the opening 12 and in cross-section. When the curved wall 14a is formed a portion of the Fibonacci series as shown in Fig. 4 and described above, this also has the effect of making the shape of the loudspeaker conform more accurately to a true

Fibonacci spiral and has the added benefit of improving sound reproduction of the 20 loudspeaker 1. As shown in Fig 4, the void 13 is generally horn-shaped.

While only having the wall 11 formed from a part of a Fibonacci spiral improves sound reproduction and quality of the sound emitted through the opening 12 from the transducer 20 of the loudspeaker 1, it has been found that this can be further improved by also forming the wall 14a from a part of the Fibonacci spiral.

In use, the loudspeaker 1 is turned on or off by power switch 30 which is the combined switch and light emitting diode (LED), as indicated by the box in phantom in Fig. 7A.

When the loudspeaker is on, the LED is illuminated. When the loudspeaker is turned on by the switch 30, it causes the microcontroller 24 to control the battery manager to provide power to the microcontroller 24 from the rechargeable battery 22 and/or an external power supply connected to the USB-C port 7. When the enclosure 3 is mounted on the housing and the circuit 40 is electrically coupled to the circuit 36, the microcontroller can also draw power from any of the rechargeable battery 35, the solar 10 panel 4 and an external power supply connected to the USB-C port 31 via the battery manager 33. The solar panel 4 can be used to charge rechargeable battery 35. The solar panel can also be used to charge the rechargeable battery 22 when the transducer enclosure 3 is mounted in the housing 2 and the connectors 5 are in contact with the connectors 6. The microcontroller 24 uses the power to power itself and to 15 power the battery managers 28, 33, the protection circuit 34, the USB charge control circuits 27, 32, the DAC 25, the ADC 26, the LED in the switch 30, the Bluetooth ® controller 23 and the amplifier 21.

If an external or remote sound source device has a Bluetooth capability, electrical 20 sound signals can be streamed wirelessly to the loudspeaker 1 via the Bluetooth® controller 23. Alternatively, an electrical sound source can be connected via a cable to the audio jack 8 so that music is streamed from the source to the loudspeaker 1 via a physical cable and converted to a digital signal by the ADC 26. After being received at the loudspeaker 1 either by a cable at the audio jack 8 and being converted to a digital signal by the ADC 26 or by the Bluetooth® receiver 23, the sound signal is passed to the microcontroller 24 and then through the DAC 25, which converts the digital signals to analogue signals, to the amplifier 21. The amplifier 21 amplifies the received analogue signal and outputs the amplified signal to the transducer 20 to convert the sound from an electrical signal to an audible sound energy. The audible output from the transducer is then transmitted into the void 13 and exits the speaker 1 via the opening 12 as sound energy in the form of sound waves. The DAC 25 also passes the analogue sound signal to an output audio jack 9. If another loudspeaker (not shown), such as another loudspeaker 1, is connected to the jack 9, the loudspeaker 1 and the other loudspeaker can be used to create a stereo sound.

The housing 2 can be manufactured from any suitable material, such as wood, plastic, metal or a composite material. Similarly, the transducer enclosure 3 can also be manufactured from any suitable material, such as wood, metal, plastic or a composite material.

As described above, an advantage of the invention is that by forming the loudspeaker 1 with a void that is at least partially defined by a wall formed from a Fibonacci spiral the accuracy of the sound reproduction from the loudspeaker 1 is improved and sound quality is improved.

Claims

1. A loudspeaker comprising:

a housing comprising a curved housing wall at least partially defining a void

5 having an opening;

an electroacoustic transducer adapted to be mounted to the housing; and wherein when the electroacoustic transducer is mounted to the housing, sound generated by the transducer is directed into the void, and a curve of the curved housing wall is defined by a first portion of a Fibonacci spiral so that the curve extends from the 10 electroacoustic transducer to the opening, so that the sound from the transducer is emitted from the housing through the opening.

2. A loudspeaker according to claim 1, wherein the curved housing wall also forms an external wall of the housing.

3. A loudspeaker according to claim 1 or claim 2, wherein the plane of the curved housing wall is curved in only one dimension and is straight in another dimension.

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4. A loudspeaker according to claim 3, wherein the curved dimension and the straight dimension are substantially perpendicular to each other.

5. A loudspeaker according to any of the preceding claims, wherein the transducer is mounted in the housing, in use, such that the transducer is adapted to emit sound in a direction that is substantially parallel to a first plane that is transverse to the curved housing wall.

6. A loudspeaker according to claim 5, wherein the first plane is substantially

5 perpendicular to the curved housing wall.

7. A loudspeaker according to any of the preceding claims, wherein the separation between the curved housing wall and the transducer increases from the transducer towards the opening.

8. A loudspeaker according to any of the preceding claims, wherein the portion of the Fibonacci spiral defining the curve is defined by a number of sequential terms in the Fibonacci series.

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9. A loudspeaker according to claim 8, wherein three adjacent terms in the

Fibonacci series are used to define the spiral.

10. A loudspeaker according to claim 8 or claim 9, wherein the terms ofthe Fibonacci series that are used to define the part of the Fibonacci are less than or equal to the

20 10th term.

11. A loudspeaker according to any of the preceding claims, wherein the transducer is mounted in an enclosure on the housing.

12. A loudspeaker according to claim 11, wherein the enclosure is removably mounted on the housing.

13. A loudspeaker according to claim 11 or claim 12, wherein the enclosure

5 comprises an enclosure wall that comprises a curved surface.

14. A loudspeaker according to claim 13, wherein an end of the curved surface of the enclosure wall is adjacent an end of the curved housing wall when the enclosure is mounted in the housing.

15. A loudspeaker according to claim 14, wherein the curved surface of the enclosure wall and the curved housing wall together form a substantially continuous curved surface.

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16. A loudspeaker according to any of claims 13 to 15, wherein the curve of the curved surface of the enclosure wall is defined by a second portion of a Fibonacci spiral.

17. A loudspeaker according to claim 16, wherein the second portion of the Fibonacci 20 spiral is defined by at least two terms of the Fibonacci series.

18. A loudspeaker according to claim 17, wherein the terms of the Fibonacci series defining the second portion of the Fibonacci spiral are less than or equal to the 10th term of the Fibonacci series.

19. A loudspeaker according to any of claims 16 to 18 when dependent on any of claims 8 to 10, wherein the second portion of the Fibonacci spiral is defined by the terms of the Fibonacci series immediately adjacent and below the terms defining the first portion of the Fibonacci spiral.

20. A loudspeaker according to any of claims 13 to 19, wherein the enclosure wall comprises a curved portion and a non-curved portion.

21. A loudspeaker according to any of claims 13 to 20, wherein the plane of the 10 enclosure wall of the transducer is substantially transverse to the first plane.

22. A loudspeaker according to claim 21, wherein the enclosure wall plane is substantially perpendicular to the first plane.

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23. A loudspeaker according to claim 21 or claim 22, wherein the enclosure wall plane and a plane defined by the curved housing wall are substantially parallel in a direction perpendicular to the first plane.

24. A loudspeaker according to any of the preceding claims, wherein a cross-section 20 of the void defined by the housing is substantially polygonal.

25. A loudspeaker according to claim 24, wherein the cross-section is a quadrilateral.

26. A loudspeaker according to any of the preceding claims, wherein the transducer is located at one end of the first portion of the Fibonacci spiral and the opening is located at the other end.

5

27. A loudspeaker according to any of the preceding claims, further comprising an electrical power source.

28. A loudspeaker according to claim 27, wherein the electrical power source is one or more of: a battery; and a solar panel.

29. A loudspeaker according to claim 28, wherein the electrical power source comprises both a solar panel and a battery, the battery being rechargeable and the solar panel is adapted, in use, to charge the rechargeable battery.

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30. A loudspeaker according to any of claims 27 to 29, wherein the transducer is mounted in an enclosure that is removably mounted on the housing and the electrical power source is mounted on the enclosure to enable the enclosure to be used as a loudspeaker separate from the housing.

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31. A loudspeaker comprising a housing, a transducer and an enclosure, the transducer being mounted in the enclosure and the enclosure being adapted to be removably mounted in the housing, in use, and wherein when the enclosure and transducer are removed from the housing, the enclosure and transducer can be used as a loudspeaker without the housing and when the enclosure is mounted in the

25 housing, the enclosure, transducer and housing together form the loudspeaker.

32. A loudspeaker according to claim 31 wherein the loudspeaker is also in accordance with any of claims 1 to 30.

Intellectual

Property

Office

Application No: GB1621837.2 Examiner: Peter Easterfield