AU738580B1 - Loudspeaker enclosure system - Google Patents

Description

AUSTRALIA

Patents' Act 1990 COMPLETE SPECIFICATION STANDARD PATENT LOUDSPEAKER ENCLOSURE

SYSTEM

The following statement is a full description of this invention, including the best method of performing it known to me: 3 0 APR 2001 PCT/AUOO/00816 Received 01 May 2001 -1- LOUDSPEAKER ENCLOSURE SYSTEM: This invention relates. to and for the improvement of audio sound reproduction by conventional dynamic loudspeakers relevant to any given loudspeaker enclosure volume and related electrical power consumption, and in particular concerning the efficient and effective extention and reproduction of the lower audio frequencies, with a subsequent reduction in distortion together with an improvement in the transient response at such frequencies.

It has long been difficult to accurately and efficiently reproduce the lower frequencies of the audio spectrum by traditionally adopted loudspeaker enclosures without the application of large volume speaker enclosures, or smaller enclosures requiring high electrical power consumption with respective high power capacity speakers.

These difficulties are somewhat overcome by the current invention of which adopts in reverse function the principle of biological transmission and reception of sound by and with a tympanic cavity or middle ear, in that there is a stage in the process of the system for the transmission and propagation of sound by and with the assistance of a tympanic chamber, that is a controlled pressure cavity or chamber to dampen and limit any distortion from being produced by the loudspeakers employed in the enclosure in the propagation of the low to middle audio frequencies, by and with a specified sum of opposing acoustic phasing of such frequencies within a specified cavity or chamber of the enclosure.

In one form of the invention the loudspeaker enclosure system consist of a number of open back dynamic loudspeakers, and may consist of at least four speakers with two large speakers and two small speakers having in total about half the active cone area as the large speakers employed, which are mounted in a dual chamber enclosure with one of the large speakers mounted within the enclosure on an internal baffle forming a partition for a large acoustic suspension or bass reflex chamber, with the other large speaker mounted in common direction thereto immediately in front thereof together with the two smaller speakers mounted adjacent and near thereto on a front baffle forming a small tympanic chamber of the enclosure by and with the two large speakers and one only of the small speakers being electrically connected to operate in common acoustic phase to each other with the other small speaker electrically connected to operate in opposing phase thereto.

In other forms of the invention the loudspeaker enclosure system may incorporate any number of large speakers of the low and or to medium and or to the full audio frequency range, with any necessary electrical circuitry of medium to or high audio frequency attenuation, together with about the same number of smaller or other speakers employed to total AMFNDED

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i.! PCT/AUOO/00816 Received 01 May 2001 -2as near as possible the same active cone area as half the number of larger speakers employed, which may be of the full audio frequency range, or of the low and or to medium audio frequency range, and eleotrically coupled with any necessary crossover network therefore to a suitable number of high audio frequency range speakers independently enclosed adjacent or near to the small or other speakers employed; with half the number of smaller or other speakers connected in common electrical or acoustic phase with all the large speakers employed, and the other half number of the smaller or other speakers connected in opposing phase thereto.

The dual chamber loudspeaker enclosure of the system should preferably be constructed so as to reduce as much as practicable its any audio frequency resonances, with the larger acoustic suspension or bass reflex chamber enclosing half the number of large speakers employed, being of an internal volume according to the general parameters for and with the particular speakers so employed and enclosed. The smaller tympanic chamber of the enclosure should preferably be of sufficient internal volume to accommodate the half number of large speakers and such relevant number of smaller or other speakers employed, with any cross-section area of the chamber being equal to not less than the total active cone area of the smaller speakers mounted therein. Both chambers of the enclosure should preferably be adequately lined internally with an appropriate acoustic absorption material to limit internal chamber resonances.

It is also preferable that the respective smaller speakers employed in the tympanic chamber of the loudspeaker enclosure system be mounted at a distance from the larger speakers employed, equal to twice the distance of that which is provided for between the respective larger speakers mounted in common direction to and in line with each other in the bass reflex and tympanic chambers of the enclosure.

This distance should be measured from a point approximately midway between the vertexes of the cones or voice coils of the larger speakers and the vertex of the cone or voice coil of the respective smaller speakers employed in the system, to reduce the effects of acoustic phase cancellation at frequencies of and relevant to half the physical wave length of the distance between the respective speakers so enclosed and employed in the system.

The speakers or a number thereof mounted on the front baffle of the enclosure may be respectively inclined to some degree in opposing directions of each other to provide for or improve the distribution of monophonic or bi-channel stereophonic or surround sound propagation from the enclosure.

The large and small speakers employed in the enclosure should preferably be as near as possible of similar cone compliance and sensitivity with the same impedance; or be so electrically connected so as to provide as near as possible the same AMENDED

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PCT/AU00/00816 Received 01 May 2001 3 respective impedance as between the total of large and the total of small speakers employed. The small speakers employed should preferably have as near as possible in total at least half the active cone area as the total of large speakers employed, and preferably have not less than half the power capacity in watts as the larger speakers employed.

To assist with an understanding of this invention the attached drawing Figure 1 shows one example of the invention with the following text in explanation thereof:- The loudspeaker enclosure system consist of two identical large speakers of low to middle audio frequency range (1A 1B), together with two identical smaller speakers of full audio frequency range (2A 2B), having about half the active cone area as the larger speakers (1A 1B). The speakers are mounted within a dual chamber enclosure The large speaker (1A) is mounted within the enclosure on an internal baffle which forms a partition for a large bass reflex chamber (3A) with a tuned vent or port area and is internally lined with acoustic absorption material(6).

The large speaker 13) is mounted in common direction with the large speaker (1A) immediately in front thereof on a front baffle which forms a smaller tympanic chamber (3B) of the enclosure, and is also lined internally with acoustic absorption material The two smaller speakers (2A 2B) are also mounted in common direction adjacent and near to the large speaker (1B) in the tympanic chamber (3B) of the enclosure The large speakers (1A 1B) and the small speaker (2B) are electrically connected in common phase to each other, with the other small speaker (2A) being connected in opposing electrical phase thereto. The speakers are respectively terminated in pairs at suitable connectors at the rear of the enclosure to provide for alternative impedance or .connection for monophonic or bi-channel stereophonic or surround sound applications. When activated by an appropriate electrical audio signal the speakers (1A,1B,2A 2B) and chambers (3A&3B) of the enclosure react with and upon each other in such a manner so as to effectively dampen and control and to efficiently reinforce and propergate the reproduction of sound over a broad audio frequency range with minimum distortion and maximum transient response.

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PFA/AU

Claims (4)

1. A loudspeaker enclosure system consisting of at least four speakers with two large low or full audio frequency range speakers and two small full audio frequency range speakers having in total about half the active cone area as the large speakers employed, which are mounted in a dual chamber enclosure with one of the large speakers mounted within the enclosure on an internal baffle forming a partition for a large acoustic suspension or bass reflex chamber, with the other large speaker mounted in common direction thereto immediately in front thereof together with the two smaller speakers mounted adjacent and near thereto on a front baffle forming a small tympanic chamber of the enclosure by and with the two large speakers and one only of the small speakers being electrically connected to operate in common acoustic phase to each other with the other small speaker electrically connected to operate in opposing phase thereto.

2. A loudspeaker enclosure system of claim 1 hereof consisting of more than four open back dynamic loudspeakers.

3. A loudspeaker enclosure system of claim 1 or 2 hereof with additional high audio frequency range loudspeakers independently enclosed and mounted in or near to either chamber of the enclosure and electrically connected with any necessary cross- over network to operate and propagate the high audio frequencies from the enclosure.

4. A loudspeaker enclosure system substantially as herein described with reference to the accompanying drawing. APiFICANT: DATED: 3 0 APR 2001 noe John Charles AMENDED SHEET- IPEA/AU