WO2008107853A1

WO2008107853A1 - Acoustic diffusion enclosure

Info

Publication number: WO2008107853A1
Application number: PCT/IB2008/050820
Authority: WO
Inventors: Jean-Michel Capt
Original assignee: Jmc Lutherie Sa
Priority date: 2007-03-07
Filing date: 2008-03-06
Publication date: 2008-09-12

Abstract

The invention relates to an acoustic diffusion enclosure (1) comprising a diaphragm (2) and at least one electromagnetic actuator (5.1 through 5.4) attached to said diaphragm (2), one or more barriers (3.1 through 3.5) attached to the diaphragm, a means for supplying power to said actuator(s) in order to activate said diaphragm (2) and an elastic support (7, 8) attached to at least one of said barriers and to a cover (12), said support also carrying means (16) for mounting the enclosure.

Description

ACOUSTIC DIFFUSION SPEAKER

Field of the invention

The present invention relates to an acoustic diffusion chamber. More specifically, the present invention relates to a musical instrument that creates a very present acoustic climate from any audio source (HiFi) or instrumental (guitar, violin), replacing or in addition to traditional speakers.

State of the art

The principle of speakers or speakers is known in the state of the art. So, to produce sounds, you have to vibrate the air. A loudspeaker is a kind of motor, usually it consists of a mobile electric coil immersed in the magnetic flux of a magnet. The coil is secured to a movable membrane cardboard or synthetic material, stretched on a frame that secures the whole. When an electric current is passed through a wire which is placed in a magnetic field, this wire is subjected to so-called Laplace forces, which can set the wire in motion. The loudspeaker first transforms the current that is assigned to it in motion of the coil. This sets the membrane of the loudspeaker in motion, which itself sets the air in motion. The sound perceived by a man or an animal being by nature a vibration of the air, the loudspeaker "transforms the electric current into sound". There are several types of speakers for example:

electrodynamic, isodynamic, electrostatic, piezoelectric and plasma. The electrodynamic loudspeaker, covering about 99% of the market, today still has a relatively simple operation for a mass technology. A so-called traditional speaker, as described above for example, aims at the transparency of sound. To achieve this goal audiophiles work with inert materials and use technology to set the sound. In this view of the mind, one essentially addresses the ears thus depriving the sound of a good part of its spectrum and its energy.

It should be noted that a soundboard is excited in different ways: with strings rubbed, plucked or struck, by sympathy with the sound emitted by a musical instrument, using electromagnetic transducers, using electric Piezo transducers, using a traditional loudspeaker fixed on it or by sympathy, using metal or bamboo slats, using a mechanism of a music box or at the same time using a bell watch.

Principle of the invention

The object of the present invention is to improve the known devices.

More particularly, an object of the present invention is to provide an enclosure that has a better rendering of sound regardless of the source used (instrument or device).

Another goal is to propose a speaker that pleases music lovers.

The enclosure according to the invention is an enclosure worked with luthier techniques.

The applied philosophy is the acceptance of the color generated by the use of resonance wood. The result is very close to concert music, in that the sound retains all its dimensions. Unlike known products, the enclosure according to the invention uses no speaker to produce sound. It is formed of a membrane that is set in motion using mechanical electro-magnetic transducers. The use of a hood closing the back of the speaker can break the course-circuit of bass specific to the technology of the flat speakers. All the proportions of the system are based on proportions related to the Golden Number (1.618). The elements are proportionate and located in relation to each other according to the sequence of the natural numbers of Fibonacci, namely: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ... gets each number by adding the two that preceded it. The division of two consecutive numbers (the largest by the smallest) gives a result very close to the golden ratio. The unit of measure chosen is the centimeter. For example, the membrane measures 89 cm side and frame frame 55 cm side. On the other hand, the inner square measures 34 cm on the side. The actuators are positioned 34 cm from the outer edges. As the invention has been sized according to this proportion, it is found in many places.

The membrane is preferably suspended by four anchor points located on vibration nodes in such a way that the energy generated by the actuators is distributed on the membrane and not in the frame.

The frame includes a frame attached to the membrane and a square core attached to a support. These two elements are interconnected by an elastic cable (or other equivalent means) which serves as a damper and keeps the energy in the membrane. Everything is fixed by a single anchor point to the wall or floor by a tripod. Filters are installed on the core of the frame and connected to the actuators, thus guiding the response of the enclosure. As an accessory, an active box can be installed between the speaker and a preamplifier stage, allowing to direct the sound according to the use (location and type of music). The philosophy that led to the creation of this instrument delight music lovers with a technology that allows the vibration of a soundboard, and it is luthier techniques that can guide the sound of the speakers according to the invention .

The invention will be better understood by the description of embodiments thereof and the appended figures in which

FIG. 1 shows a first perspective top view of the enclosure according to the invention;

FIG. 2 shows a second perspective rear view of the enclosure according to the invention;

FIG. 3 shows a perspective and exploded view of the enclosure according to the invention and

Figure 4 shows a detail of the enclosure.

detailed description

In a first embodiment, the chamber 1 comprises a square wooden membrane 2, for example in neighborhood resonance spruce in this embodiment.

In this mode, the dimensions of the membrane 2 are (for example) 890 x 890 x 4.5 mm (width x height x thickness) approximately. It is vaulted using dams 3.1, 3.2, 3.3, 3.4, 3.5 glued-laminated resonance spruce (for example) in a radius of 3 m approximately. Five dams 3.1 to 3.5 are installed according to this mode to shape the membrane 2. The dams are positioned on nodes of vibration, that is to 22% of the length of the fibers (either for this mode with 195 mm with the axis of the dam about). In this mode, the two outer dams 3.1 and 3.5 are about 15 mm thick, the two anchorages 3.2 and 3.4 are about 20 mm thick and the central dam 3.3 10 mm thick. Preferably, all are rounded on the top and scalped at both ends so as to balance the frequencies and orient the sound. Of course, the dimensions and the number of dams indicated above form an exemplary illustrative embodiment and variations (in size and number) are possible within the scope of the present invention.

The two dams that will serve as anchoring 3.2 and 3.4 to the frame (see later in this description) are glued on nodes of vibration, that is to say about 22% of the edge of the membrane 2. On the two anchorages 3.2 and 3.4 are fixed 4 bolts 4.1 to 4.4, to be planted (eg inserts), also located at about 22% of the length of the edge fibers. The membrane 2 thus formed is driven by four electromagnetic actuators 5.1, 5.2, 5.3, 5.4 mechanically glued on easels 6.1, 6.2, 6.3, 6.4.

In one embodiment, each actuator 5.1 to 5.4 produces a signal of 15 W for 8 Ω. Preferably, these are wired in series in two groups.

The easels 6.1 to 6.4 are of two kinds. The first 6.1 and 6.3 which favor the bass are rather long and directed towards the center of the membrane 2 while the other two 6.2 and 6.4 smaller, are directed outwards and favor the high frequencies. For example, the easels 6.1 to 6.4 may be in the form of drops of water, in resonance spruce and are about 10 mm thick. The shortest are about 150 mm long and the longest about 300 mm long. They are focused at 22% of the length of the fibers of the upper and lower edges on the one hand and on the other hand about 340 mm from the side edges.

In one embodiment, there is a distance of approximately 185 mm between the axes of the dams 3.1 and 3.2, a distance of approximately 250 mm between the axes dams 3.2 and 3.3 and respectively 3.3 and 3.4, and a distance of approximately 185 mm between the axes of dams 3.4 and 3.5.

The membrane is varnished preferably on both sides with a violin varnish, allowing the membrane to vibrate freely.

The frame is an elastic frame fixed on the two barriers 3.2 and 3.4 described above, this using four silentblocs "coil shape" 18 (see below in the present description).

More specifically, the frame comprises a frame 7 and a square 8, both, for example cross birch about 12 mm thick, and varnished to prevent them from working with moisture.

In this mode, the frame 7 is 550 x 550 mm and approximately 45 mm wide and the inner square 8 is approximately 340 x 340 mm. These two parts are interconnected by means of an elastic means, in this case an elastic cable 9 of aeronautical quality of about 4 mm in diameter. On the upper and lower crosspieces of the frame 7 are fixed four dampers 10 (see Figures 3 and 4) annular rubber, 170 mm from the side edges, and used to support the actuators. On the central square 8 are installed: a connector 15 of traditional speaker type (adapted for connection with different types of amps and connected to the actuators), a filter for guiding the signal delivered to the actuators and a system of 16. The latter is a Tom Holder, namely a fastener usually installed on the Toms of the batteries. Four silentblocs 11.1, 11.2, 11.3, 11.4 "coil form" are still fixed and serve for fixing the cover 12 which closes the enclosure on the rear through the openings 13.1, 13.2, 13.3, 13.4. The vaulted cowl 12 is made using cross-poplar, for example. The two sides used to shape the top are about 15 mm thick while the top itself is about 4 mm thick. The outer dimensions of the hood are approximately 820 x 820 mm. The top is reinforced in its center by a square poplar cross 4 mm 340 x 340 mm approximately, pierced with 4 holes 13.1 to 13.4 for fixing hood to the square of the frame. The center is pierced with a circular opening 14 of approximately 200 mm in diameter. The outside and the inside of the hood 12 may be sheathed with a fabric (for example black). The interior is preferably lined with a damping material, to break the acoustic short circuit of the bass. In order to allow the membrane of the enclosure to vibrate freely and still to seal the enclosure, the edges of the cover 12 are equipped with a foam strip, for example 15 mm thick by 15 mm wide (not shown ).

As is understood from the previous description and drawings, the frame 7 is itself fixed on the membrane 2 by means of fastening means (screws 17, four in all in this embodiment) which each carry a rubber mount 18, said screws 17 being screwed into the inserts 4.1 to 4.4, as illustrated in FIG.

The enclosure is fixed on a stand or on a wall support (not shown) via the fastening system 16.

An active equalization box can optionally be installed between an amplification system and the speaker 1. This element offers two advantages: the first is the possibility of being able to calibrate the sound according to the type of music listened to and the second it is the possibility of being able to direct the sound according to the listening place. Developed for the enclosure of the present invention, this accessory can just as easily be installed in a conventional sound system.

Of course, all the dimensions, shapes, materials and values indicated above are given as illustrative and non-limiting examples and variations are possible within the scope of the present invention with other materials, dimensions etc. , depending on the circumstances. More specifically, it may be varied in the context of the present invention in particular,

- square or rectangular dimensions / shapes

- thicknesses - quarter-cut gems (eg cedar, mahogany, maple, sitka, spruce) or other equivalent materials

- dams (other forms, positioning, dimensions)

- the number of actuators and their type

- easels: variable sizes and different materials (eg carbon)

- dimensions, materials, and shapes of frames 7 and 8 (inside and outside)

- The type of elastic material connecting parts 7 and 8, for example it can be formed by a membrane - the type of speaker connection.

In another mode, the dimensions of the membrane 2 are 550 x 550 mm (width x height).

In another variant, the material chosen for the instrument or soundboard is cedar.

In another variant, the dimensions of the membrane 2 are in a ratio which is substantially equal to the Golden number.

The sound is colored according to the types of construction desired by the luthier. The number of actuators preferably varies between 2 and 6, connected in different ways to orient the sound.

Application fields

For listening to music

- Private (private use) - Concert halls

- Museum

- Waiting places, hotels

For the amplification of instruments

- Guitarist

- Other musician

- Music Group

- Recording Studio - Live Recording

- Retailer or music store

- Music school

As is easily understood, the enclosure according to the invention may form part of a complete system formed in particular from a source (for example a musical instrument) and the enclosure. In particular, if a guitar is used as an instrument (or other similar wooden instrument), the membrane can be made in the same material as the instrument's soundboard

(eg wood, or even from the same tree) to optimize the rendering and color of the sound produced. Of course, this principle is not limited to guitar and wood and other variants or combinations of instruments and / or materials are possible. As such, the lutherie technique allow many choices of materials, and therefore many variations and source-speaker pairs, depending on the desired sound reproduction and coloring of the desired sound in application of the present invention.

Claims

claims

1. acoustic diffusion chamber (1) comprising a membrane (2) and at least one electromagnetic actuator (5.1 to 5.4) fixed on said membrane (2), one or more dams (3.1 to 3.5) fixed to the membrane, means supplying said actuator (s) to activate said membrane (2) and an elastic support (7,8) attached on the one hand to at least one of said dams and on the other hand to a hood (12). ), said support further carrying means (16) for fixing the enclosure.

2. Enclosure according to claim 1, wherein the membrane has a rectangular shape or the like.

3. Enclosure according to claim 1 or 2, wherein the membrane has a rectangular shape and the dimensions of the order of 890 x 890 x 4.5 mm (width x height x thickness).

4. Enclosure according to one of the preceding claims, wherein the membrane is wood.

5. Enclosure according to the preceding claim, wherein the wood is selected from the list including spruce, cedar, mahogany, maple, sitka or spruce.

6. Enclosure according to one of the preceding claims, wherein the membrane is curved along a radius of curvature.

7. Enclosure according to the preceding claim, wherein the radius of curvature is of the order of 3m.

8. Enclosure according to one of the preceding claims, which comprises 5 dams (3.1 to 3.5).

9. Enclosure according to claim 8, wherein the dams are spaced from each other by 185 mm, respectively about 250 mm.

10. Enclosure according to one of the preceding claims, which comprises four electromagnetic actuators (5.1 to 5.4).

11. Enclosure according to one of the preceding claims, wherein each actuator is glued on an easel (6.1 to 6.4).

12. Enclosure according to the preceding claim, wherein the easels have different dimensions.

13. Enclosure according to one of the preceding claims, wherein the elastic support comprises an outer frame (7) and an inner frame (8), said frames being connected by an elastic means (9), the outer frame being fixed to the at least one of said dams, the internal frame carrying the connector (15) for supplying the actuators and the support (16) for fixing the enclosure.

14. Enclosure according to one of the preceding claim, wherein the proportions / dimensions of the components between them are related to the Golden number.

15. Acoustic system, comprising an enclosure according to one of the preceding claims and a musical instrument.

16. The system of claim 15, wherein the soundboard of the musical instrument is made of the same material as the membrane.

17. The system of claim 16, wherein the material is the wood of violin making.