Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
  • H04R1/40—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers
  • H04R1/403—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers loud-speakers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R3/00—Circuits for transducers
  • H04R3/12—Circuits for transducers for distributing signals to two or more loudspeakers

Definitions

• Electroacoustic transducer system for sound recording or reproduction
• the invention concerns an electrical transducer system of the type described in the introduction to claim 1, wherein the transducers can be loudspeakers or microphones. Where the system is to be used especially for the stereophonic reproduction of music, the transducers are loudspeakers.
• an electroacoustic transducer system of the type described in the introduction to claim 1 are known from US-PS no. 4 399 328.
• This transducer system is similar to the present application's 2k+l transducer units, in that the transducer units for the most part have identical directivity patterns and each transducer unit includes a transducer and an amplitude control device in order to regulate the conversion factor to the associated transducer unit, so that the transducer units which are arranged symmetrically relative to a central transducer unit have conversion factors with the same value.
• phase shift of the transducer units is the same, apart from the fact that the phase shift in one of the transducers in each pair of the transducer units, which, are arranged symmetrically around the central transducer in such a way that each transducer in the pair is situated at a distance from the central transducer unit which is an odd multiple of the distance d___ between each transducer, amounts to a phase difference of 180°.
• the object of this invention is, by means of a simple network, to obtain a conversion of the sound waves, which is substantially independent of frequency and direction, by means of a suitable choice of conversion factors which can be regulated by the amplitude control device. This is achieved by connecting the transducers in a series-parallel network.
• stereophonic reproduction or recording of sound where two electrical transmission channels are used called the right and left channels respectively, it has proved difficult to achieve a satisfactory sound image.
• the primary objective of stereophonic reproduction or recording of sound, and above all music is to reproduce in a natural way the three-dimensional sound field at the recording site either for storage by a recording medium or by reproduction in an electroacoustic transducer system.
• both in recording and reproduction in a two-channel system it has proved difficult to obtain a satisfactory reproduction of the sound image, i.e. the three- dimensional sound field.
• the object of the present invention is therefore to be able to render the impression of three-dimensionality of the sound field which is to be recorded or reproduced.
• This object is achieved by an electroacoustic transducer system which is characterized in those features described in the characterising portion of claim 1. Further features and advantages are described in the attached independent claims.
• electroacoustic transducers in said embodiments are loudspeakers for reproduction of sound, particularly music, without this in any way limiting the scope of the invention.
• Fig. 1 is a schematic representation of an electroacoustic transducer system in accordance with the invention, comprising five loudspeakers.
• Fig. 2 shows is a schematic wiring diagram for the system in fig. 1, where the loudspeakers are shown as impedances.
• - Fig. 3 is a schematic wiring diagram in accordance with the invention for seven loudspeakers shown as impedances.
• Fig. 4 is a schematic wiring diagram in accordance with the invention for nine loudspeakers shown as impedances.
• Fig.l shows five loudspeakers 1-5 connected in a parallel network in such a way that loudspeakers 1, 3 and 5 are connected in parallel and loudspeaker 2 is connected in inverse parallel between the negative terminal on loudspeaker 1 and the positive terminal on loudspeaker 3, i.e. the negative terminal on loudspeaker 2 is connected to the positive terminal on loudspeaker 3 and the positive terminal on loudspeaker 2 to th negative terminal on loudspeaker 1.
• loudspeaker 3 and loudspeaker 5 a fourth loudspeaker 4 is connected in direct parallel.
• loudspeakers or transducers are arranged in a line at an equal distance d, so that loudspeakers 2 and 4 constitute a symmetrically arranged pair in relation to the central loudspeaker 3, with the pair's transducers connected in such a way that they are in counter- phase or has a mutual phase shift of 180°.
• the electrical wiring diagram for the transducer system in fig 1 is shown in fig. 2, in that the individual loudspeakers are schematically described as impedances Z1-Z5. It is a well-know fact that an electroacoustic transducer in the shape of a loudspeaker can be regarded as a combination of a resisitive and a reactive impedance, the latter in the form of an inductance which must be identified with the loudspeaker coil if electrodynamic loudspeakers are involved.
• the reactive impedance is of course a capacitance.
• fig. 3 shows the connection diagram for a configuration with seven loudspeakers, wherein two counter-phased pairs of loudspeakers, symmetrical in relation to the central loudspeaker, are used, in that each of these pairs has a symmetrical distance in relation to the central loudspeaker which is an odd multiple of the fixed mutual distance d between each of the loudspeakers Z11-Z17.
• loudspeakers Z13 and Z15 together with Zll and Z17 respectively constitute the counter-phased pair.
• fig. 4 shows a configuration with 9 loudspeaker elements Z21-Z29, where two symmetrical pairs are used connected in counter-phase, viz. Z24 and Z26,and Z22 and Z28 respectively.
• the electroacoustic transducer system i.e. the stereophonic loudspeaker system designed in accordance with the invention
• the electroacoustic transducer system was compared with a pair of conventional electrodynamic loudspeakers, with separate units for bass, mid- range and treble and use of cross-over filter.
• This system was supplied by a recognized producer in the field. The listening tests showed that regardless of the programme material, the reproduction of the sound image emerged with a far better impression of space and three-dimensionality than was the case with the known loudspeaker system. Alterations in the source directivity gave the impression of a steady transition without any concentration on one channel or the other, and monophonic signals were centred exactly between the two channels.
• the transducer system had a relatively flat dynamic frequency response in the reproduced frequency range, which, however, did not include the 2 or 3 lowest octaves of the audible range.
• a surprising result was that the impression of the sound image was also maintained when the test subject moved in relation to the loudspeaker units, i.e. that direction and distance from the listening point to the loudspeakers were not critical, in that the impression of space and three- dimensionality was retained when the position in relation to the loudspeakers was highly asymmetrical.
• the loudspeakers could maintain the impression of a coherent sound image even when the distance between the loudspeakers was up to double the distance between the test " subject and the centre of the line between the loudspeakers.
• the well-known hole-in-the- iddle effect which is so often heard in conventional systems.
• the loudspeakers may well be full frequency units, i.e. providing a relatively flat dynamic response over the entire audible frequency range. If loud ⁇ speaker units with a smaller frequency range are used, these should in every case cover the six to seven highest octaves of the audible frequency range, while one or two bass loudspeakers are used simultaneously in order to reproduce the frequency range below 200 Hz.
• the transducers which are used as loud ⁇ speakers can either be of the electrodynamic type, ribbon or foil loudspeakers or electrostatic loudspeakers. In the last two cases, the transducers can constitute sections of transducers in the form of foils or ribbons.
• the transducer system in accordance with the invention can also be used for recording sound, above all music.
• the transducers will consist of microphones, which can be either electrodynamic or capacitive.
• an electroacoustic transducer system which, when the transducers are in the form of loudspeakers used for the reproduction of music, above all provides the opportunity to achieve an exceptionally high- quality loudspeaker system which can be constructed with relatively small loudspeaker elements and which in a version with, e.g. , only five elements in each system, i.e. with a total of ten elements in a loudspeaker pair for stereophonic music reproduction, can provide a loudspeaker system at a reasonable price and with moderate dimensions, while at the same time the sound reproduction is better than for much more expensive systems.
• the transducer system in accordance with the invention is particularly suitable for private hi-fi systems for home use.

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• Health & Medical Sciences (AREA)
• Otolaryngology (AREA)
• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• General Health & Medical Sciences (AREA)
• Circuit For Audible Band Transducer (AREA)
• Stereophonic System (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=19892192

Family Applications (1)

Country Status (2)

Cited By (2)

Citations (2)

• 1989
  • 1989-06-28 NO NO892701A patent/NO168500C/no unknown
• 1990
  • 1990-12-27 WO PCT/NO1990/000195 patent/WO1992012604A1/en not_active Ceased

Patent Citations (2)

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