GB2530787A

GB2530787A - A method and a member comprising a composite material

Info

Publication number: GB2530787A
Application number: GB1417459.3A
Authority: GB
Inventors: Craig Milnes
Original assignee: WILSON BENESCH Ltd
Current assignee: WILSON BENESCH Ltd
Priority date: 2014-10-02
Filing date: 2014-10-02
Publication date: 2016-04-06
Also published as: GB201417459D0

Abstract

A member 101 comprising a composite material and configured to be mounted on or within an audio apparatus, the composite material comprising reinforcing fibres 102, a matrix 103 at least partially surrounding the reinforcing fibres and graphene particles 104 dispersed within the matrix. The matrix may comprise an epoxy or polymeric material and the reinforcing fibres are preferably carbon fibre. The graphene particles may comprise no more than 10 layers and may be homogenously dispersed throughout the matrix. The member may comprise a component of a speaker unit such as a diaphragm or housing, or a turntable such as a platter or tonearm. In a method for manufacturing the member a material comprising a plurality of graphene particles dispersed within a resin is obtained. The material is then moulded around a plurality of reinforcing fibres to form the member. The graphene containing material may be applied as a sheet or in liquid form.

Description

TITLE

A method and a member comprising a composite material

FIELD OF THE INVENTION

Embodiments of the present invention relate to a method and a member comprising a composite material. In particular, they relate to a method and a member comprising a composite material in an audio apparatus.

BACKGROUND TO THE INVENTION

Components for use within audio equipment are known to be manufactured from a carbon fibre and resin composite. An example is provided by the applicants earlier patent application published as GB2482655 A. This document discloses a sealed gas impervious tonearm tube for a gramophone record player. The tonearm is made from carbon fibre and epoxy resin composite, and a vacuum is provided to the interior in order to pre-stress and damp the structure without any additional mass.

BRIEF DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION

According to various, but not necessarily all, embodiments of the invention there is provided a member as claimed in claim 1.

The graphene particles present within the composite forming the member provides the advantage that the member is provided with improved stiffness and audio damping compared to similar products formed without the g rap he ne.

According to various, but not necessarily all, embodiments of the invention there is provided a method as claimed in claim 22.

According to various, but not necessarily all, embodiments of the invention there is provided an adhesive as claimed in claim 30.

The member may be for use within an audio apparatus.

The phrase "audio apparatus" used herein means audio equipment that is used to generate sound or used to generate signals, such as electronic signals, in an audio system, or to other apparatus that is subject to sound waves generated by such audio equipment and which is arranged such that vibrations within the apparatus are transferrable to audio equipment.

For example, the audio equipment may comprise a loudspeaker unit for generating sound in response to received electrical signals, an amplifier used to generate electrical signals for supply to a loudspeaker unit, a gramophone record turntable, etc. Other apparatuses that are subject to sound waves generated by such audio equipment and which are arranged such that vibrations within the apparatus are transferrable to the audio equipment include tables, stands, etc. used to support audio equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of various examples of embodiments of the present invention reference will now be made by way of example only to the accompanying drawings in which:

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE

INVENTION

The Figures illustrate a member 101 comprising a composite material and configured to be mounted on or within an audio apparatus (e.g. 201), the composite material comprising: reinforcing fibres 102; a matrix 103 at least partially surrounding the reinforcing fibres 102; and graphene particles 104 dispersed within the matrix.

The fibres may all be carbon fibres, but some embodiments are envisaged where the reinforcing fibres comprise at least some glass fibres, or another type of fibres known for use in reinforcing sheet material.

The matrix 103 may be formed of a synthetic resin such as epoxy resin, or polyester (polyethylene terephthalate) or polyether ether ketone or another organic thermoplastic polymer.

The graphene particles may each comprise a single graphene layer, or a few graphene layers (for example up to ten graphene layers). The particles have relatively long dimensions along the graphene layer(s) compared to their thickness. The particles may be nano-platelets having a longest dimension of between 0.1 and 100 micrometres (microns). Typically, the particles have an average size of 6 micrometres (microns) and a thickness of less than 2 nanometers. Particles used to form the composite material may be obtained in a powder form, for example from Applied Graphene Materials plc of the UK.

The graphene within the composite as used in member 101 provides the composite with properties that are useful in a number of situations relating to an audio apparatus, or equipment subjected to vibrations or sound waves.

When compared to existing composite materials formed of carbon fibres and synthetic resins, the graphene provides the composite with increased heat conductivity, which is useful where the composite may be used to assist in the transportation of heat away from a heated object.

When compared to existing composite materials formed of carbon fibres and synthetic resins, the graphene also increases the damping of vibrations or sound waves passing through it.

It some situations, the composite may be used to construct a member having an inner surface defining a chamber containing a partial vacuum. The inner surface defining the chamber comprises the matrix containing graphene particles, and the graphene is believed to resist outgassing of the matrix and therefore assist with the production and maintenance of the vacuum.

As used herein the phrase "partial vacuum" means space in which gaseous pressure is less than atmospheric pressure.

In some examples at least a portion of the matrix used to form the composite material forms a mixture containing graphene particles, and within that portion of the matrix the graphene particles comprise at least 3% by mass of the mixture. Typically the concentration of the graphene particles will be such that they comprise no more than 15% by mass of the mixture, and in some embodiments it may be preferable to keep the concentration of graphene particles such that the graphene particles comprise no more than 10% by mass of the graphene/matrix mixture.

Depending upon the use of the composite material a higher concentration of graphene may be advantageous. For example, where higher conductivity is required the graphene particles may comprise at least 5% by mass of the mixture.

An example of a member 101 comprising a composite material and configured to be mounted on or within an audio apparatus is shown in side view in Fig. 1A and the plan view of Fig. 1D. An enlarged view of a portion of the reinforcing fibres 102 of the member 101 is shown in Fig. lB and a schematic cross-sectional view of the member 101 is shown in Fig. 1 C. The composite material comprises reinforcing fibres 102, a matrix 103 at least partially surrounding the reinforcing fibres 102 and graphene particles 104 dispersed within the matrix.

The fibres 102 are formed into bundles of fibres, such as bundles 105A, 105B, 105C and 1OSD, which are woven into a sheet 106 as illustrated in Figs. 13 and 1C.

The matrix 103 may surround the reinforcing fibres such that it is located to on both sides of the sheet 106 and also between the fibres of the sheet.

In the present example the fibres 102 are all carbon fibres, and the matrix 103 comprises epoxy.

The graphene particles 104 may be dispersed substantially homogeneously throughout the matrix 103, as in the present example. In an alternative example the graphene particles may be predominantly concentrated to one side of the sheet 106. For example, the graphene particles may be more concentrated within the matrix 103 on one side 107 of the sheet 106 than the other side 108 (shown in Fig. IC). Alternatively, the graphene particles may be concentrated around a particular region or regions of the sheet 106. For example, the graphene particles may be relatively concentrated within a central region 109 (shown bounded by dashed line in Figs. lAand 1D).

In the example of Figs. 1A to 1D, the member 101 comprises a diaphragm lOlA for a dynamic drive unit of a speaker unit (that is, a loudspeaker for a speaker unit). As shown in Fig 1A, the diaphragm lOlA is roughly the shape of a truncated cone and has a substantially circular outer edge 110 (as shown in Fig 1 D) and a substantially circular inner edge 111 defining a central hole 112.

In an alternative to diaphragm lOlA, the diaphragm comprises two layers of the carbon fibre, graphene and resin composite spaced apart by a core layer, which may be formed of cork. That is, the cork is laminated with a layer of the composite material on each of its two sides. The laminated material provides a rigid structure that is provided with additional damping by the cork layer.

The diaphragm lOlA is shown mounted within a dynamic drive unit 201 in the side cross-sectional view of Fig 2A, the perspective cross-sectional view of Fig. 2B and the front view of Fig. 2C. The inner edge 111 of the diaphragm lOlA is attached to a voice coil former 202 and the spider 203 of the dynamic drive unit 201, while the outer edge 110 is attached to a surround 204 which is attached to the frame 205 of the dynamic drive unit 201.

A voice coil 206 is mounted on the voice coil former 202, and the voice coil is arranged to be immersed in a magnetic field provided by a magnetic pole piece 207. During operation, a signal current is passed through the voice coil 206 to induce vibrational movement of the voice coil 206, the former 202 and diaphragm lOlA and thereby produce sound. The signal current also generates heat within the voice coil which must be dissipated. If the coil becomes too hot, dimensions of some parts within the dynamic drive unit 201 can be changed sufficiently to cause stationary parts to interfere with moving parts. Advantageously, the graphene in the composite forming the diaphragm provides the diaphragm with increased heat conductivity. Consequently, heat is conducted away from the voice coil into the diaphragm lOlA where it may be conducted away by surrounding air.

In the example where the diaphragm lOlA has graphene concentrated within the region 109 (shown in Figs. 1A and 1D) the location of the region 109 is adjacent to the voice coil former 202 so that heat may still be conducted away from the former 202.

In an alternative example of the dynamic drive unit 201, the voice coil former 202 is itself formed of the same, or similar, type of composite material as the diaphragm lOlA. That is, the voice coil former 202 may also comprise a composite material comprising reinforcing fibres, a matrix at least partially surrounding the reinforcing fibres and graphene particles dispersed within the matrix. In this instance a slit may be provided along the former 202 or a gap may be formed along the conducting material of the former 202 so that the former 202 does not form a continuous electrically conducting ring and interference with the electrical properties of the coil by the former 202 is avoided.

As shown in Figs. 2A, 2B and 2B, the dynamic drive unit 201 also comprises a dust cap 208. The dust cap 208 may be formed of a material known for use as a dust cap. However, in an example the dust cap is itself a member formed of the same, or similar, type of composite material as the diaphragm lOlA. That is, the dust cap may also comprise a composite material comprising reinforcing fibres, a matrix at least partially surrounding the reinforcing fibres and graphene particles dispersed within the matrix.

A method of manufacturing a member to be mounted on or within an audio apparatus is shown in the flow chart of Fig. 3. The method comprises obtaining a material comprising a plurality of graphene particles dispersed within a resin at block 301. At block 302 the material is moulded around a plurality of reinforcing fibres to form the member. In examples, the reinforcing fibres are in the form of a woven sheet.

An example of the method of Fig. 3 is shown in Fig. 4. In this method, the fibres are in the form of a woven sheet, and the fibres are pre-coated with a thermoplastic resin. That is, the fibres are in the form of pre-impregnated composite fibres or a "pre-preg". The pre-preg 401 is placed over a suitably shaped metal mould 402 to which heat may be applied, for example by a hot plate or an oven.

A solid sheet of material 403 comprising a resin loaded with graphene particles is then located over the pre-preg sheet so that a face of the material 403 is against a face of the pre-preg sheet. A peel ply 404 is then laid over the material 403 before a breather cloth 405 is laid over the peel ply. A silicone cover (or bag) 406 is then positioned over the assembled layers 401, 403, 404 and 405. A vacuum pump (not shown) is then used to evacuate the bag 406 as indicated by arrow 407 so that air pressure presses the bag down against the assembled layers. The assembled layers are then heated so that the resin in the pre-preg 401 and the resin of the resin/graphene sheet material 403 softens (or melts) to allow the resin material to flow around the reinforcing fibres present in the pre-preg 401. The assembly is then allowed to cool before the resulting member formed of composite material is removed from the mould.

In one such example of this method, the resin used is PET (polyethylene terephthalate) which is heated to about 220 degrees so that it is able to flow as a liquid.

In a similar method to that described in the previous paragraph, instead of the graphene particles being provided in a sheet of resin material, the graphene particles are present in the resin used to form the pre-preg.

An alternative example of the method of Fig. 3 is shown in Fig. 5. In this example, a sheet of woven reinforcing fibres 501 is positioned over a mould 502. In this example, the fibres 501 are not previously coated with resin as they were in the previous example. That is the fibres are bare. A silicone cover (or bag) 503 is then located over the sheet of fibres 501. In this example, a first port 504 of the bag 503 is connected via a tube 505 to a reservoir of graphene loaded resin 506 and a second port 507 of the bag is connected to a vacuum pump (not shown).

The graphene loaded resin 506 in the reservoir is liquid. It may be formed, for example by firstly mixing epoxy resin with a quantity of graphene powder to produce a graphene loaded epoxy resin. Immediately before use, the graphene loaded epoxy resin is then mixed with a hardener.

By applying a vacuum to the port 507 of the bag 503, the graphene loaded resin 506 is forced under air pressure into the bag 503 so that is flows around the fibres of the sheet 501. The resin 506 is allowed to harden before the member formed of a composite of resin, graphene and reinforcing fibres is removed from the mould.

A further alternative example of the method of Fig. 3 is shown in Fig. 6. A sheet of woven reinforcing fibres 601 is positioned over a lower part 602 of a mould 603. In this example, the fibres 601 are woven into a sheet and they are not previously coated with resin. An upper part 604 of the mould is then positioned over the lower part 602 of the mould. The upper part 604 and lower part 602 are configured to define a cavity 605 in which the sheet of fibres 601 is positioned. The mould 603 has a first duct 606 to the cavity 605 and a second duct 607 to the cavity. A vacuum pump (not shown) is connected to the second duct 607 while the first duct is connected to a reservoir of graphene loaded resin (not shown) in liquid form. The graphene loaded resin may be prepared as described above for the example of Fig. 5.

A vacuum is applied to the duct 607 which causes the graphene loaded resin to be forced into the mould under air pressure so that it flows around the fibres of the sheet 601. The resin is then allowed to harden before the member formed of a composite of resin, graphene and reinforcing fibres is removed from the mould 603.

In a variation of this latter method, the resin may be forced into the mould under a pressure greater than atmospheric pressure, and in one such example no vacuum is applied to the second duct 607.

The latter examples that use the two part mould of Fig. 6 have the advantage of providing a surface finish that depends upon the surface finish of the interior surfaces of the mould 603. The surface finish can therefore be made as smooth as desired. Furthermore, the dimensions of the member can be made with repeatable accuracy, which may be of importance where other components are to be assembled on, in, or to, the member. (One such example is described below, where the member comprises an amplifier housing into which components must be assembled.) The dynamic drive unit 201 is shown in Fig 7 mounted in a speaker unit 701.

The dynamic drive unit 201 is attached to a front panel 702 of the speaker unit 701. The front panel 702 is itself attached to a speaker cabinet 703.

The front panel 702 is shown on its own in Fig. 8. The front panel defines an aperture 801 for receiving the dynamic drive unit 201, and may have other apertures, such as aperture 802 for receiving other dynamic drive units. The front panel 702 may be constructed from a metal core 803 which is provided with a composite skin 804 over the core; the composite skin being formed of reinforcing fibres, a matrix at least partially surrounding the reinforcing fibres and graphene particles dispersed within the matrix.

The composite skin 804 provides the front panel 702 with enhanced stiffness and reduces resonances in the front panel.

In an alternative example, the metal core may be replaced with a laminated structure formed of several layers of metal laminated with layers of the composite material formed of resin, graphene and carbon fibre.

A portion of the speaker cabinet 703 is shown in Fig. 9. The cabinet 703 comprises a core 901 formed of a closed cell foam polymer material. In the present example the core is formed of a thermo-formable closed cell foam polymer material. A layer of glass-fibre material 902 covers the core 901 and a layer of carbon-fibre material 903 covers the glass-fibre material. The carbon-fibre material is impregnated with a graphene loaded resin as described above. The glass fibre layer 902 provides damping of sound vibrations in the cabinet.

The carbon-fibre, graphene and resin composite layer 903 provides the structure with rigidity. The graphene improves the stiffness of the composite layer and also provides damping of vibrations within the cabinet wall.

It may be noted that, Fig. 9 shows an exposed portion of the core 901 and an exposed portion of the glass-fibre layer. However, in reality, the glass-fibre layer 902 completely covers the core 901 and the carbon fibre/graphene composite layer 903 completely covers the glass fibre layer 902.

Head phones 1000 comprising a pair of speaker housings 1001 are shown in Fig. 10. Each of the housings 1001 comprises a member formed of composite material comprising reinforcing fibres, a matrix at least partially surrounding the reinforcing fibres, and graphene particles dispersed within the matrix. The housings 1001 are cup-shaped and may be formed of one or more layers of carbon fibre material, and they may be manufactured in a moulding process as described above with respect to Figs. 3 to 6. The carbon fibre provides shielding of the interior of the housings 1001 from audio energy that may be present external to the housings. Thus, when a user wears the headphones, the user's ears are shielded from background sound generated outside of the headphones. In addition, the graphene within the composite material forming the housings will provide further damping of the sound.

An audio amplifier 1100 comprising an amplifier housing 1102 is shown in Figure 11. The amplifier housing 1102 comprises a member 1101 formed of composite material comprising reinforcing fibres, a matrix at least partially surrounding the reinforcing fibres, and graphene particles dispersed within the matrix. In the present example the member 1101 provides five sides of the box-like housing 1102. A sixth side is provided by a top cover 1103. The cover 1103 may also be formed of the same composite material.

Generally] audio amplifiers are exposed to audio energy which can cause the amplifier housing and electronic components within the housing to vibrate.

The vibration is particularly problematic for amplifiers comprising valves, but transistors, printed circuit boards and other electronic components may also generate unwanted microphonic signals. The composition of the housing 1101 reduces this problem in the amplifier 1100. The carbon fibre and graphene provides a very stiff structure that, as a result, has relatively high resonance frequencies. In addition, the graphene provides increased damping of the audio energy to further reduce the problem.

Generally, audio amplifier housings are made of metal so that components of the amplifier that generate heat are able to lose heat through the walls of the housing. However, to ensure good rigidity of the housing, and so avoid microphonic problems, the housing is made from a heavy gauge of material, which results in a heavy product. However, in the present amplifier 1100, the graphene provides the composite walls of the housing with good thermal conductivity to allow the heat to be dissipated from the electronic components within, while the composite provides the necessary rigidity from a relatively low mass of material.

The member 1101 forming the amplifier housing 1102 may be moulded of composite material as described above. To ensure accurate dimensions of the interior of the housing, while providing the desired surface finish to the exterior, the method described with reference to Fig. 6 may be preferred.

A further member 1201 comprising a composite material and configured to be mounted on or within an audio apparatus is shown in the perspective view of Fig. 12A and the cross-sectional view of Fig 12B. Like the previous examples, the composite material comprises reinforcing fibres, a matrix at least partially surrounding the reinforcing fibres, and graphene particles dispersed within the matrix.

The member 1201 differs from the previous examples in that the member has an inner surface 1202 defining a chamber 1203 containing a partial vacuum.

Consequently the walls of the member 1201 are pre-stressed by air-pressure present on the outside surface 1204 and a lack of air pressure present on the inside surface. The pre-stressing of the walls of the member 1201 results in the member being less inclined to transfer audio energy along its length.

Furthermore, the resonant frequencies of the walls of the member are raised by the pre-stressing.

The member 1201 may be in the form of a sealed cylindrical tube, as shown in Figs. 12A and 12B, that is provided with a vacuum valve 1205. The cylindrical tube forming the member 1201 may be moulded and then end caps bonded in place. One end cap 1206 may be provided with the vacuum valve 1205. After forming a vacuum tight envelope the chamber 1203 may be evacuated by a vacuum pump through the valve 1205.

Advantageously, the inner surface 1202 comprises the matrix containing graphene particles, and the graphene particles tend to prevent the resin from outgassing into the evacuated chamber 1203. Consequently the vacuum may be maintained for a longer period of time compared to a similar member that does not include the graphene within the resin of the composite.

The vacuum valve 1205 may be bonded into the end cap 1206, using an epoxy loaded with graphene. Consequently, outgassing of this epoxy is also reduced by the presence of the graphene. The end cap may be bonded to the end of the tube wall using the same type of graphene loaded epoxy resin.

The member 1201 may form a part of a piece of an audio apparatus that is used to support other audio equipment. For example, the member 1201, along with other similar members, may form a part of a table and may be used to support a table top, which itself may be used to support the audio equipment. The audio equipment may be for example a turntable for playing records, a microphone, or other equipment that may be adversely affected by audio energy.

The member 1201 may be formed of just several layers of woven carbon fibre sheet. Alternative the carbon-fibre/graphene composite may be formed over a core tube. For example, at least a part of the length of the tube forming the member 1201 may comprise a metal tube within the composite material.

A similar member 1301 to member 1201 is shown in Fig 13. The member 1301 differs from member 1201 in that it is not cylindrical but has a curved and tapering shape to its outer wall. The member 1301 may be used as a tonearm on a turntable for playing records. A similar tonearm is disclosed in GB2482655. However, the tonearm 1301 of Fig. 13 differs from that of G32482655 in that it is formed of a composite material that also comprises graphene. Consequently the tonearm 1301 benefits from improved audio damping and improved internal vacuum provided by the graphene.

A platter 1401 for a turntable for playing records is shown in cross-section in Fig. 14. The platter 1401 comprises a core 1402 over which is formed a layer 1404 of composite material comprising reinforcing fibres, a matrix at least partially surrounding the reinforcing fibres, and graphene particles dispersed within the matrix.

The core 1402 comprises a polymer material and is formed in a growth additive manufacturing process. The structure of the core defines internal hollow chambers, such as chamber 1403. The layer of composite material 1404 is applied all around the core to provide a vacuum tight skin, and the chambers within the core are evacuated to create a partial vacuum.

During manufacture the upper surface 1405 of the platter may be formed against a mould to provide the required surface finish while the lower surface 1406 is formed under the pressure of a silicone bag in a resin infusion process.

Air pressure that is present on the outside and vacuum on the inside of the outer layer 1404 of the platter 1401 causes the layer to be pressed against the core 1402. Consequently, the structure is stiffer than it would otherwise be, and sound vibrations are damped more than they would otherwise be.

The graphene in the composite layer 1404 also provides the layer with additional stiffness and reduces the rate of outgassing by the resin in the composite layer 1404 into the vacuum.

A portion of another member 1501 comprising a composite material and configured to be mounted on or within an audio apparatus is shown in Fig. 15.

The composite material again comprises reinforcing carbon fibres, a matrix at least partially surrounding the reinforcing fibres, and graphene particles dispersed within the matrix. The member 1501 comprises a cylindrical tube which forms an outer wall of a vacuum isolated loudspeaker cable 1500. One of two similar end portions of the loudspeaker cable 1500 is shown in Fig 15.

The cable 1500 comprises a metal conductor 1502 and a glass tube 1503 which extends along a middle portion of the conductor 1502. The ends of the glass tube 1503 are vacuum sealed by ceramic end caps 1504 through which extend the conductor 1502. The member 1501 extends along the length of the glass tube 1503 and metal end caps 1505 are bonded to the ceramic end caps 1504 and to the member 1501.

A first copper tube 1506 is bonded in an aperture in the ceramic end cap 1504. This first copper tube is used to evacuate the space between the conductor 1502 and the inside of the glass tube 1503. A second copper tube 1507 is bonded in an aperture in the side wall of the member 1501. The second copper tube 1507 is used to evacuate the space between the inside surface of the member 1501 and the outside surface of the glass tube 1503.

The copper tubes may be pinched off to provide a vacuum tight seal.

The bonds between the various components of the loudspeaker cable 1500 are required to provide a vacuum tight seal. In the present example, the bonds are made using an epoxy resin loaded with graphene particles. As discussed above, the graphene particles reduce outgassing of the epoxy resin and therefore facilitate the formation of a vacuum and also increase the duration for which the vacuum exists after production. That is, the rate of increase in pressure over time is reduced by the presence of the graphene in the epoxy.

Graphene within the resin forming the composite material of member 1501 also has the effect facilitating the formation of a vacuum within the member 1501 and also increasing the duration for which the vacuum exists after production.

Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed.

Features described in the preceding description may be used in combinations other than the combinations explicitly described.

Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not.

Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

I/we claim:

Claims

CLAIMS1. A member comprising a composite material and configured to be mounted on or within an audio apparatus, the composite material comprising: reinforcing fibres; a matrix at least partially surrounding the reinforcing fibres; and graphene particles dispersed within the matrix.
2. A member according to claim 1, wherein the graphene particles are dispersed substantially homogeneously throughout the matrix.
3. A member according to claim 1 or claim 2, wherein the reinforcing fibres comprises carbon fibres.
4. A member according to any one of claims 1 to 3, wherein the matrix comprises epoxy or a polymeric material.
5. A member according to any one of claims 1 to 3, wherein the matrix comprises at least one of a group consisting of epoxy, polyester, polyethylene terephthalate, and polyether ether ketone.
6. A member according to any one of claims 1 to 5, wherein at least a portion of the matrix forms a mixture containing graphene particles, and within said portion of the matrix the graphene particles comprise at least 3% by mass of the mixture.
7. A member according to claim 6, wherein within said portion of the matrix the graphene particles comprise at least 5% by mass of the mixture.
8. A member according to claim 6 or claim 7, wherein within said portion of the matrix the graphene particles comprise no more than 15% by mass of the mixture.
9. A member according to claim 6 or claim 7, wherein within said portion of the matrix the graphene particles comprise no more than 10% by mass of the mixture.
10. A member according to any one of claims 1 to 9, wherein at least the majority of the graphene particles each comprise no more than ten layers of g rap he ne.
11. A member according to any one of claims 1 to 10, wherein the reinforcing fibres are woven.
12. A member according to any one of claims 1 to 11, wherein the reinforcing fibres are woven to form a sheet and the graphene particles are more concentrated to one side of the sheet than the other side.
13. A member according to any one of claims 1 to 12, wherein the member comprises a component of a speaker unit.
14. A member according to any one of claims 1 to 13, wherein the member comprises a diaphragm for a dynamic drive unit of a speaker unit.
15. A member according to claim 14, wherein a central portion of the diaphragm comprises a higher concentration of graphene particles than a portion surrounding the central portion.
16. A member according to any one of claims 1 to 13, wherein the member forms a part of a housing of a speaker unit.
17. A member according to any one of claims 1 to 12, wherein the member forms a part of a housing for an audio amplifier.
18. A member according to any one of claims 1 to 12, wherein the member comprises a platter for a turntable.
19. A member according to any one of claims 1 to 12, wherein the member comprises a tonearm for a turntable.
20. A member according to any one of claims 1 to 19, wherein the member has an inner surface defining a chamber containing a partial vacuum and the inner surface comprises the matrix containing graphene particles.
21. A member according to any one of claims 1 to 20, wherein the member comprises said composite material formed about a core material.
22. A method comprising: obtaining a material comprising a plurality of graphene particles dispersed within a resin; and moulding the material around a plurality of reinforcing fibres to form a member to be mounted on or within an audio apparatus.
23. A method according to claim 22, wherein the reinforcing fibres form a 24. A method according to claim 22 or claim 23, wherein the moulding comprises laying a sheet of the material over the reinforcing fibres and applying heat to cause the material to flow around the reinforcing fibres.
24. A method according to claim 22 or claim 23, wherein the reinforcing fibres form a woven sheet, the material is pre-coated onto the carbon fibres and the moulding comprises applying heat and pressure to change the shape of the woven sheet.
25. A method according to claim 22 or claim 23, wherein the material is in a liquid form and the moulding comprises causing the material to flow from a reservoir and around the reinforcing fibres.
26. A method according to any one of claims 22 to 25, wherein the method comprises locating the reinforcing fibres in the cavity of a mould, the mould being formed of two parts which form the cavity when assembled together.
27. A method according to any one of claims 22 to 26, wherein the moulding comprises applying a vacuum to the reinforcing fibres.
28. A method according to any one of claims 22 to 27, further comprising mounting the member on or within apparatus to produce an audio apparatus.
29. A method according to any one of claims 22 to 27, further comprising mounting the member on or within equipment to produce audio equipment.
30. An apparatus comprising a plurality of components and an adhesive, the plurality of components being bonded together by the adhesive to form a chamber, wherein the chamber comprises a partial vacuum, the adhesive is exposed to the partial vacuum and the adhesive comprises a plurality of graphene particles dispersed throughout epoxy resin.