EP1788844A2 - Public address system,method for generating spatial sound images and software - Google Patents

Abstract

The system has a set of network nodes (K5-K9) for outputting individual audio signals (E5-E9) assigned to the network nodes. A network (2) is provided for the nodes and designed for transmission of digital data, where an audio signal (10) is transmitted over the network and the individual audio signals are generated from a temporal segment of the audio signal (10) through application of reproduction parameters. The network nodes are connected with loudspeakers (5-9), and a control unit and a data source are formed in a device unit. Independent claims are also included for the following: (1) a method for generating spatial sound images (2) a computer program with a program code unit for generating spatial sound images.

Description

State of the art

The invention relates to a sound system for generating spatial sound images based on an audio signal with a plurality of loudspeaker supply units for outputting individual audio signals individually assigned to the loudspeaker supply units and to a network via which the loudspeaker supply units are connected to one another, wherein the audio signal is transmitted via the network and / or transferable, and wherein the individual audio signals can be generated and / or generated from the audio signal by using reproduction parameters, as well as a method for generating spatial sound images and a correspondingly designed software program.

Public address systems are used in almost all major public buildings, such as Museums, schools or government agencies, or private company buildings, are used to send people, who are in the buildings, through loudspeaker announcements, for example, information, voice prompts or warning signals.

Furthermore, automatic systems for visitor guidance are common in which time-triggered announcements are triggered at different locations. However, these announcements are broadcast separately, so that visitors can, for example, go to exhibit in a museum of exhibits and receive the corresponding information text at each new location.

From the publication DE 4218105 A1 is a synchronized loudspeaker relay system for low-distortion large-volume public address known. The system has a plurality of loudspeakers for the sound of a large space, wherein between a recording microphone, in which a speaker speaks, and the individual speakers each have a storage device is connected. The storage devices are used to delay the sound output of the respective downstream speaker, so that the sound output takes place only when the sound from the recording or from an upstream speaker sound waves arrive. In this way, the sound waves from the recording location and from the speakers are synchronized with each other and achieved a low-distortion sound of large rooms.

The utility model DE 29804231 U1 relates to an arrangement and supply of similar speakers to achieve a directivity. In this case, it is provided to achieve the directivity of a loudspeaker arrangement by using path differences, time delays and phase rotations or phase shifts. This is implemented by, for example, broadcasting an unprocessed audio signal via a first loudspeaker and an audio signal in phase opposition thereto via a second loudspeaker, the audio signals originating from a common signal source equalized in the frequency response.

The publication GB 2362739 , which is probably the closest prior art discloses an audio system with a plurality of speakers, each speaker is assigned an individual address and a plurality of audio channels are transmitted via a control unit. Through the individual address, it is possible to address a particular speaker so that it receives a particular audio channel from the plurality of audio channels. In addition, information about parameters such as volume, delay and frequency response are passed to the individual speakers, for example, the delay is used to reduce unwanted reverberation or echo effects through the plurality of speakers.

Disclosure of the invention

According to the invention, a sound system for generating spatial, in particular variable, sound images on the basis of an audio signal is proposed. The sound images are preferably location-dependent and / or time-dependent acoustic intensity distributions, which are generated by the sound system, and in particular cause a hearing impression of a traveling noise source, wherein the audio signal is formed for example as a warning signal, announcement or music sequence. In particular, the audio signal is a closed and / or content-related sequence. The public address system is used for example and as explained in the introduction in public buildings such as museums, schools or government offices or in corporate buildings and is preferably used to guide people in a dangerous situation safely to an exit of the building. In particular, voice announcements or warning signals are broadcast with the public address system. Other uses include automated guided tours of museums or other buildings.

The public address system has a multiplicity of loudspeaker supply units which are connected via a network. The network is preferably designed as an electrical / electronic wiring and / or as a radio link. The loudspeaker supply units are designed to output individual audio signals and are preferably connected to loudspeakers for broadcasting the individual audio signals.

It is provided that playback parameters for controlling the output of the individual audio signals can be specified and / or fixed. These display parameters preferably comprise parameters for signal shaping in addition to parameters for selecting time subsections of the audio signal. The audio signal is preferably transmitted unprocessed via the network, in particular to the loudspeaker supply units, and / or is preferably transferable, preferably in such a way that all steps and / or the essential steps of the signal processing for generating a loudspeaker supply unit individual individual audio signal in the loudspeaker supply units are carried out are formed.

According to the invention, the individual audio signals can each be generated from a temporal subsection of the audio signal, in particular in such a way that by applying the playback parameters to the audio signal, a temporal subsection of the audio signal the individual speaker supply unit is assigned as a single audio signal for output. In particular, an individual single audio signal is thus generated for the individual loudspeaker supply units from the unprocessed audio signal, which comprises only a temporal subsection of the audio signal, in other words a section of the unprocessed audio signal. The individual individual audio signals assigned to the different loudspeaker supply units preferably do not overlap and / or only partially overlap.

With the device according to the invention, it is possible to generate effects of spatially traveling announcements or signals. These effects can be used to advantage, e.g. to realize in the event of danger an intuitive guidance to the nearest emergency exit, whereby a feeling of slow-moving signals is generated in a listener or visitor. It is particularly advantageous that the audio signal has to be fed into the network in unprocessed form only once and / or has to be transmitted via the network, and the loudspeaker supply unit-specific signal preparation is decentralized, generally in the loudspeaker supply units. Usually, in known systems, a suitable signal is precalculated centrally for each loudspeaker supply unit and transmitted separately to the respective loudspeaker supply unit at the right time. On the one hand, this leads to a high computation load for the central signal conditioning device and, on the other hand, to a high network load due to the multiplicity of individual audio signals to be transmitted separately. The invention thus minimizes the complexity of the system and in particular saves transmission capacities of the network.

Preferred or advantageous embodiment of the invention are given by the following description and the dependent claims.

In a preferred embodiment of the invention, the network is designed to transmit digital data. As a network topology, for example, a ring structure or a tree structure can be used. Advantageously, the network is designed for synchronous data transmission and / or for transmission of a common time base, so that the synchronization of the Speaker supply units to each other in a simple manner with respect to the synchronous clock and / or the common time base.

In an advantageous development, the loudspeaker supply units are designed as network nodes or have a network node. In particular, each network node in the network has an individual address via which the network node can be selectively addressed. The training as a network node is a simple integration of additional, also designed as a network node or the same having speaker supply units in existing networks possible. In addition, extensive experience with networks from other technical fields can be used in the implementation of the invention. Preferably, each loudspeaker supply unit has its own arithmetic unit, which is designed, for example, as a DSP (digital signal processor) and which is designed to apply the reproduction parameters to the unprocessed audio signal. In particular, the loudspeaker supply units designed as reproducing network nodes operate synchronously with each other and / or use the same time base.

In a preferred embodiment of the invention, it is provided that the reproduction parameters are fixed in particular in or on the individual loudspeaker supply units and / or are adjustable or can be programmed during operation and / or programmed.

The fixed setting of the playback parameters, for example, by an operating unit on the speaker power units. If the playback parameters are programmed during operation, these are transmitted, for example, by a direct communication with a control unit, the communication taking place via the network already described above or a second network. Alternatively, the rendering parameters are communicated along with the audio stream over the network, for example as additional headers.

The playback parameters preferably include any combination of the following parameters: playback volume, preferably designed as the maximum volume during playback. Start time, preferably formed as an absolute time based on the common time base or the common synchronous clock or formed as relative time, in particular relative to the start time of the unprocessed audio signal. Stop time, preferably formed as an absolute or relative time, analogous to the start time, or as an implicit indication calculable from the other parameters and other information. Fade time, preferably the time between start time and reaching the playback volume. Blanking time, preferably the time between leaving the playback volume and the stop time.

In order to produce further, more complicated sound images, the combinable reproduction parameters furthermore include the following parameters: fade-in level, preferably the volume at the start time. Blanking level, preferably the volume at the stop time. Complex volume / time functions, with which preferably the individual audio signal is modulated. Furthermore, functions for phase shifting the audio signal can be used.

According to the invention, a method is also proposed for generating spatial sound images based on an audio signal, which is preferably carried out using the sound system according to the invention or one of the embodiments. In a first step, a particularly unprocessed audio signal is transmitted identically to a multiplicity of loudspeaker supply units. In particular, the audio signal is simply transmitted via the network, eg as a common data packet or as common data packets for all loudspeaker supply units. By means of reproduction parameters, after the transmission to the loudspeaker supply units, the output of the audio signal is divided into different loudspeaker supply units, wherein in the loudspeaker supply units an individual temporal subsection of the audio signal for the broadcasting is processed as a single audio signal via an associated loudspeaker. The transmission of the audio signal and the reproduction parameters is preferably carried out successively, wherein either the audio signal or the reproduction parameters are transmitted first, or in parallel, for example in a common data packet or on two data lines.

The method thus has the advantage that the audio signal for all or all participating loudspeaker supply units via the network only has to be transmitted simply and thus the network is only slightly loaded. The computation-intensive processing of the local distribution of the individual temporal subsections of the audio signal is performed decentralized by using a tax rate designed as a reproduction parameter set.

A computer program according to the invention with the features of claim 10 has program code means for carrying out the described method, in particular in a client-server architecture. It is preferably provided that the server is designed to output the common time signal for synchronizing the clients.

• Figur 1 ein erstes Ausführungsbeispiel einer erfindungsgemäßen Beschallungsanlage in schematischer Darstellung;
• Figur 2 das Ausführungsbeispiel in Figur 1 mit verschiedenen Einzelaudiosignalen zur Veranschaulichung der Funktionsweise des Ausführungsbeispiels ebenfalls in schematischer Darstellung;
• Figur 3 ein mögliches Einzelaudiosignal in Figur 2, insbesondere zur Veranschaulichung der benutzten Terminologie;
• Figur 4 ein weiteres mögliches Einzelaudiosignal in Figur 2, ebenfalls auch zur Veranschaulichung der benutzten Terminologie.

Further features and advantages of the invention will become apparent from the following drawings and the description. Show it:

• Figure 1 shows a first embodiment of a public address system according to the invention in a schematic representation;
• FIG. 2 shows the exemplary embodiment in FIG. 1 with various individual audio signals for illustrating the mode of operation of the exemplary embodiment likewise in a schematic representation;
• FIG. 3 shows a possible single audio signal in FIG. 2, in particular for illustrating the terminology used;
• Figure 4 shows another possible single audio signal in Figure 2, also also to illustrate the terminology used.

Corresponding parts or sizes are provided in the figures with the same reference numerals.

1 shows the schematic representation of a public address system 1 as an embodiment of the invention.

The public address system 1 comprises a network 2, which is designed, for example, in a ring structure. A multiplicity of network nodes are connected to the network 2: a network node K3 connects a control unit 3 and a network node K4 a data source 4 to the network 2. network nodes K5, K6, K7, K8 and K9 are reproducing network nodes which are designed as loudspeaker supply units, and which are connected to loudspeakers 5, 6, 7, 8 and 9. Alternatively, control unit 3 and data source 4 are formed in a device unit and / or assigned to a common network node.

The control unit 3 is used to feed individual playback parameters via the network node K3 into the network 2 and to control the data source 4 and preferably has an input option for a user. In addition, the control unit 3 can take over control functions within the sound system 1. The data source 4 serves to feed an audio signal into the network 2 via the network node K4. The network nodes K5 to K9 receive the audio signal fed from the data source 4 into the network 2, each of the network nodes K5 to K9 receiving the same or identical audio signal. In addition, the network nodes K5 to K9 receive the playback parameters fed from the control unit 3, each network node receiving an individual reproduction parameter set. The network nodes K5 to K9 are synchronized with each other in time, e.g. by using the same time base or by having the network 2 as a synchronized network.

Figure 2 illustrates the generation of a sound image or event in the form of a virtual movement of a signal source using the sound system 1 in Figure 1. This effect can be used to guide people in a dangerous situation, for example, to an emergency exit. The speakers 5 to 9 are arranged in a building, a museum, a school or the like, in a row, but spaced from each other. The orientation of the speakers 5 to 9, so the direction of radiation, is set according to the local conditions in the building.

In a first step, reproduction parameters for an event are transmitted to the network nodes K5 to K9 via the control unit 3. For example, a Replay Parameter Set for an Event 1 to the network node K5 has the following content: Playback volume (Volume) : 100 fade (Fade-in) : 10 fade (Fade Out) : 10 start time (Begin) : 50 stop time (End) : 500 and is passed, eg, as a vector (K5, 100, 10, 10, 50, 500, 1), the first entry meaning that K5 is the receiver for the playback parameter set and the last entry that the playback parameters are associated with the event 1 , For example, a second event would be defined by the vector (K5, 50, 5, 5, 80, 300, 2). For a more detailed explanation of the reproduction parameters, reference is made to FIGS. 3 and 4.

In a further step, controlled by the control unit 3, an audio signal 10 is transmitted in digital form from the data source 4 to the network nodes K5 to K9. Each of the network nodes K5 to K9 forms an individual single audio signal E5 to E9 by use of the reproduction parameters, which has only a temporal subsection of the audio signal 10. The individual audio signals E5 to E9 optionally have ramps for fading in and out, etc., as will be explained in connection with FIGS. 3 and 4. The individual audio signals E5 to E9 are synchronized with each other in accordance with the playback parameters via the speakers 5 to 9 radiated. In the example in FIG. 2, an initial section of the audio signal 10 in the form of the single audio signal E5 is superimposed on the loudspeaker 5 in the form of a ramp, held in the playback volume, and then faded out in the form of a ramp. Even before fading out, the single audio signal E6 is superimposed synchronized with the radiated single audio signal E5, so that the audio signal 10 continues to be transmitted without interruption and in particular continuously and / or without offset.

In the case of a visitor in the building, the impression is given that the noise source for the audio signal 10 is from the position of the loudspeaker 5 to the loudspeaker Position of the speaker 6 changed. In this way, the virtual position of the noise source is passed from one loudspeaker position to the next, the sound source moves virtually according to arrow 11 from the position of the loudspeaker 5 to the position of the loudspeaker 9.

FIG. 3 shows an exemplary embodiment of a single audio signal E11, as used in the sound system 1 in FIG. 1 or FIG. The single audio signal E11 is shown in a coordinate system 12, along the X-axis time and along the Y-axis of the output level is plotted.

From a replay event start, which is arranged in the coordinate origin in FIG. 1, the start time 13 designates the time duration between replay event start and start of the broadcast of the single audio signal E11. The start of the replay event can be explicitly communicated to the network node and / or loudspeaker supply units by a network message or automatically detected by the latter. The stop time 14 describes the time duration between playback event start and end of the broadcast of the single audio signal E11. The reproduction volume 15 denotes the output level of the single audio signal E11 outside of the fade-in time 16 or fade-out time 17, respectively denoting the temporal duration of a ramp-shaped output level curve in the beginning section and in the end section of the single audio signal E11.

FIG. 4 illustrates a further exemplary embodiment of a single audio signal E11 * in analog representation and for the analog application, such as the single audio signal E11. In FIG. 4, a fade-in level 18, which defines an initial output level of the single audio signal E11 *, and a fade-out level 19, which defines a final output level of the single audio signal E11 *, are visualized as further optional playback parameters. Furthermore, the single audio signal E11 * is modulated with a complex volume / time function 20, which is also transmitted as a reproduction parameter to the network nodes K5 to K9. Furthermore, functions for phase shifting in the generation of the individual audio signals can be transmitted as playback parameters.

Claims (10)

Sound system (1) for generating spatial sound images based on an audio signal (10) with a plurality of loudspeaker supply units (K5, K6, K7, K8, K9) for output from the loudspeaker supply units (K5, K6, K7, K8, K9) individually assigned Single audio signals (E8, E5, E6, E7, E9) and a network (2) via which the loudspeaker supply units (K5, K6, K7, K8, K9) are interconnected, the audio signal (10) being transmitted via the network (2 ) and / or is transferable and wherein the individual audio signals (E8, E5, E6, E7, E9) can be generated and / or generated from the audio signal (10) by application of reproduction parameters (13-20),
characterized in that
in that the individual audio signals (EE8, E5, E6, E7, E9) can each be generated and / or generated from a temporal subsection of the audio signal (10). Sound system (1) according to claim 1, characterized in that the network (2) is designed to transmit digital data. Sound system (1) according to claim 1 or 2, characterized in that the network (2) is designed for synchronous data transmission and / or for transmission of a common time base. PA system (1) according to one of the preceding claims, characterized in that the loudspeaker supply units are designed as network nodes (K5, K6, K7, K8, K9) and / or have a network node (K5, K6, K7, K8, K9). Sound system (1) according to one of the preceding claims, characterized by a control unit (3) for transferring the reproduction parameters (13-20) and / or a data source (4) for transmitting the audio signal (10) via the network (2). Sound system (1) according to one of the preceding claims, characterized in that the reproduction parameters (13-20) are fixedly adjustable and / or from a common control unit (3) to the loudspeaker supply units (K5, K6, K7, K8, K9) and / or with the data stream of the audio signal (10) are transferable. Sound system (1) according to one of the preceding claims, characterized in that the reproduction parameters (13-20) comprise any combination of the following parameters: playback volume (15), fade time (16), fade time (17), start time (13), stop time (14), fade-in level (18), fade-out level (19) and / or a complex volume / time function (20) and / or functions for phase shifting the audio signal (10). A method of generating spatial sound images based on an audio signal (10), the unprocessed audio signal (10) being transmitted identically to a plurality of loudspeaker supply units (K5, K6, K7, K8, K9) and having reproduction parameters (13-20) for the individual speaker supply units (K5, K6, K7, K8, K9) a temporal subsection of the audio signal (10) for the broadcast as a single audio signal (E5 - E9) via an associated speaker (5 - 9) is processed. Method according to Claim 8, wherein the audio signal (10) is processed in such a way that an effect of a spatially traveling announcement and / or signal sequence is generated as a sound image when the individual audio signals (E5 - E9) are broadcast. A computer program comprising program code means for carrying out all the steps of any one of claims 8 or 9 when the program is run on a computer and / or when the program is distributed on a control unit (3) as server and a plurality of loudspeaker supply units (K5, K6, K7, K8, K9) as clients.

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