Audio system for open retail spaces

<u>Field of the invention</u>

The invention generally relates to an open retail space comprising a plurality of audio zones and audio systems for open retail spaces.

<u>Background of the invention</u>

For a large group of consumers shopping is an unpleasant, stressful activity. The noise in retail spaces, such as grocery stores, electronic stores, clothing stores or the like, is a major contributor to the stress experienced. The noise signals come from a plurality of noise sources such as refrigerators, freezers, ventilations systems, and other customers. As a consequence, consumers will try to shorten the time they spend in the stressful environment by taking hasty buying decisions often leading to wrong purchases. The noise problems are especially pronounced for shops having large open retail spaces such as large supermarkets or the like. The open retail space typically offers little damping of the noise signals and allows contributions from the various noise sources to accumulate thereby resulting in even higher noise levels.

Conventionally, retails shops have tried to limit the effect of the noise by playing loud music in the shops. <patcit id="pcit0001" dnum="US4953221A"><text>US4953221A</text></patcit> discloses a sound system that changes the volume of music based on measured noise levels. The audio system comprises first and second input channels and a single output channel. The first input channel is a feedback signal provided by a microphone which is placed near one of the speakers of the sound system. The second input channel receives a music signal which is being played by the sound system. The output of the sound system is a music signal which has a constant ratio relative to the noise detected in the environment. Constant power ratio operation of the system is achieved through the use of logarithmic processing of the signals in each of the input channels.

The combating of noise signals by means of loud music can, however, in itself be very stressful to the consumers thereby further worsening the noise signal problem.

There is a need in the art for improving the customers' shopping experience in open retail spaces through improved audio systems allowing adaptation of replayed audio signals to detected frequency spectra of the noise sources.

<u>Summary of the invention</u>

According to a first aspect, the invention relates to an open retail space comprising an audio system configured to provide said open retail space with a plurality of audio zones, said audio system comprising: <ul id="ul0001" list-style="none" compact="compact"><li>● a first audio zone and a second of audio zones for providing a first physical zone and a second physical zone in the open retail space with a first soundscape and a second soundscape, each audio zone comprising at least one speaker, said open retail space comprising static noise sources resulting in a first static noise signal in said first audio zone and a second static noise signal in said second audio zone, wherein said first static noise signal and said second static noise signal have a respective specific frequency spectrum;</li><li>● a multitrack player for providing said at least one speaker of said first audio zone with a first audio signal and said at least one speaker of said second audio zone with a second audio signal; and</li></ul> wherein said first audio signal has a frequency spectrum configured to perceptually mask the first static noise signal; and said second audio signal has a frequency spectrum configured to perceptually mask said second static noise signal.

An open retail space may be any space in a store or a shop, without dividing walls, selling goods to consumers or business operations. The open retail space may be part of a larger store or shop such as a floor of a department store or an individual shop of a shopping mall. The open retail space may have an area larger than 10 m2 such as between 10 and 1,000,000 m2. A soundscape may comprise any collection of music and sounds. The soundscapes may be designed to make the shopping experience more pleasant by perceptually masking detected static noise signals within the first and second audio zones. Each of the first and second soundscapes may be designed to complement the specific goods for sale or on display in the audio zone in question. In the alternative, or in addition, each of the first and second soundscapes may be designed to a specific target group of customers for the goods. The open retail space may comprise any number of audio zones such as 2, 3, 4, 6, 8, 10, 20, or more. Dimensions of an audio zone may vary widely depending on the area of the open retail space, type of goods on display in the open retail space, the number of different types of goods for sale, etc. In a number of preferred embodiments, an area of each of the first and second audio zones is comprised between 10 m2 and 2,000 m2. The speakers may be any type of electrodynamic, electrostatic, or piezoelectric speakers having a directionality appropriate for designing a given audio zone in a particular open retail space. The at least one speaker may be arranged in a ceiling above the audio zone in question. The speakers of an audio zone may be arranged in any fashion allowing the first or second audio signal to freely propagate to the first or second audio zones respectivly. In one embodiment, a plurality of speakers is arranged along a periphery of the first or second audio zones in the ceiling above the first and second audio zones.

A static noise source may be a noise source having a frequency spectrum that is approximately static over a predetermined period of time, such as respective noise signals originating from a refrigerator or a freezer during operation of the compressors, or a ventilation system. The predetermined period of time may be longer than 5 minutes, 10 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours, or more. The static noise sources may be positioned anywhere in the open retail space or outside the open retail space along or proximate to a periphery thereof. The static noise sources result in a spatially varying static noise field that can be measured as static noise signals at a particular position. The first static noise signal may be measured or detected by an appropriately positioned microphone anywhere in the first audio zone. In a preferred embodiment, the first or second static noise signal is measured at or close to a centre of the first or second audio zone to ensure that the measured noise signal is representative of the actual noise signal to which the customers in the first or second audio zone are subjected. The first static noise signal may also be an average of several static noise signals measured at different positions within the first audio zone. The second static noise signal may also be an average of several static noise signals measured at different positions within the second audio zone. The multi-track player may be any digital or analog multi-track player capable of delivering the first audio signal to the first audio zone and the second audio signal to the second audio zone. The first audio signal may be a music signal specially composed to perceptually mask the first static noise signal. The first audio signal may be designed such that its frequency spectrum fully or at least partly overlaps the frequency spectrum of the first static noise signal. The level of the first audio signal may be substantially equal to or larger than a level of the first static noise signal within a major portion of the first audio zone when measured across a perceptually relevant bandwidth such as one or more 1/3 octave frequency bands or one or more critical bands centred around a dominant frequency component of the first static noise signal.

When designing the first or second audio signal, a predetermined desired sound pressure level of the audio signal in the audio zones may be considered, as the masking characteristics of a sound are a function of the frequency characteristics and sound pressure level of the sound. The second audio signal may be a music signal specially composed to perceptually mask the second static noise signal. The second audio signal may be designed such that its frequency spectrum approximately corresponds (see above) to the frequency spectrum of the second static noise signal

In some embodiments, a first frequency interval comprising at least X% of the total energy of the first static noise signal in the human audible range comprises at least Y% of the total energy of the first audio signal in the human audible range, and a second frequency interval comprising at least X% of the total energy of the second static noise signal in the human audible range comprises at least Y% of the total energy of the second audio signal; where: <ul id="ul0002" list-style="none" compact="compact"><li>X may be any of 50, 60, 70, 80, 90, or 95%, and Y may be any of 50, 60, 70, 80, 90, or 95%. The human audible range is defined as 20 Hz ― 20 KHz.</li></ul>

Consequently, an open retail space is provided comprising an audio system that is able to effectively mask perceptually objectionable static noise signals, thereby lowering the stress induced on the customer. This will encourage the customers to spend more time in the shops, thereby reducing their risk of making wrong purchase decisions, and at the same time increasing the sales for the shop owner. The use of a plurality of audio zones will make the noise masking even more effective as the audio signals played in the individual zones can be tailormade to the noise signal present in a particular zone. The use of audio zones will additionally allow unique soundscapes to be designed for different areas of an open retail space, resulting in a better integration between the nature of commodities present in a given zone and the type or style of audio signal played in the zone. By specifically adapting the masking to static noise sources, a masking signal can be designed that can be used at any given time where the static noise source is active, in contrast to audio signals that are adapted to mask non stationary or non static noise sources. This will allow composers to create audio signals such as musical sounds or tunes specifically adapted to mask the static noise sources.

In some embodiments, a sound pressure level of the first audio signal in said first audio zone is higher than the sound pressure level of said second audio signal in said first audio zone with a predetermined amount, such as more than 3 dB, or more preferably 6 dB or even 10 dB.

The predetermined amount may be set so that the second audio signal is inaudible in the first audio zone. Other perceptually based criteria, for example A-weighted sound pressure levels, may be used to set a difference in perceived loudness between the first and second audio signals in said first audio zone in a manner reflecting the varying frequency sensitivity of human hearing.

In some embodiments, the first and the second audio zone, respectively, comprises a plurality of speakers, said plurality of speakers of the first audio zone facing approximately towards the centre of the first physical zone, and the plurality of speakers of the second audio zone facing approximately towards the centre of the second physical zone.

In some embodiments, said audio system further comprises: <ul id="ul0003" list-style="none" compact="compact"><li>● a central processing unit for controlling functionalities of said audio system; and</li><li>● a first microphone for monitoring the total background noise present in the open retail space, said total background noise comprising static noise sources and dynamic noise sources,</li></ul> wherein said first microphone is connected to said central processing unit; and said central processing unit controls the volume of each of the speakers of the first audio zone and the second audio zone based on the monitored total background noise.

The first microphone may be an omni-directional microphone suitable for recording the total background noise in the open retail space due to the identical sensitivity for background noise from all directions. The first microphone may be positioned in a position suitable for monitoring the level of the total background noise in all audio zones. The dynamic noise sources may be random in nature. Examples of dynamic noise sources may be customer-generated noise signals such as speech, yelling or banging noises, weather-induced noise due to e.g. rain and storms, noise signals from surrounding areas e.g. roads, construction sites or the like. The processing unit may control the volume of the speakers to counteract changes in the dynamic background noise such that the volume of the speakers increase to raise the sound pressure level of the first and second audio signals, when the sound pressure level of the total background noise increases. Likewise, the volume of the speakers may be turned down when the sound pressure level of the total background noise decreases so as to lower the sound pressure level of the first and second audio signals.

In some embodiments, a plurality of microphones is used for monitoring the total background noise, where an average of the signals recorded from the plurality of microphones is used as a measure of the total background noise. The average may be weighted.

In some embodiments, the central processing unit changes the volume of each of the speakers of each of the audio zones with approximately the same amount, such that the physical shape of the audio zones is kept approximately intact.

Consequently, an audio system is provided for open retail spaces that allow composers to design an individual soundscape for each audio zone, specifically designed to mask static noise signals in the zone in question, with the additional adaptive properties of being able to adjust the respective volumes of all audio zones in a coordinated manner to account for dynamic changes in the total background noise level.

In some embodiments, said open retail space is a supermarket.

In some embodiments, the playback of the first audio signal and of the second audio signal are synchronized such that the first audio signal and the second audio signal can be designed to complement each other in inter-zone or border areas between two adjacent audio zones. Thereby musical transitions from zone to zone and between the zones are optimized musically in one or more attributes of key, frequency, tempo, volume and in composition

The first audio signal and the second audio signal may be synchronized so that musical notes and other features of the second audio signal have a predetermined timing relationship with complementary musical notes of the first audio signals.

In some embodiments, the open retail space further comprises a motion-activated feature comprising: <ul id="ul0004" list-style="none" compact="compact"><li>● a sensor for detecting movement of a customer within a predetermined watch zone; and</li><li>● a processing unit for controlling functionalities of said motion-activated feature;</li></ul> wherein said sensor is connected to said processing unit and transmits a sensor signal to said processing unit, said processing unit being configured to process said sensor signal to monitor for customer movement in said watch zone and, when movement of a customer is detected, to activate the at least one speaker to play back a watch-zone specific audio signal.

In some embodiments, the motion activated feature is positioned inside an audio zone.

The sensor may be any kind of sensor suitable for detecting movement of a customer within a predefined zone such as an optical sensor e.g. a camera, an ultrasound sensor, or pressure sensors positioned in the floor. The watch-zone specific audio signal may be any audio signal such as a music signal and/or a voice signal. The watch-zone specific audio signal may comprise information related to the type of goods on display in the audio zone having the motion-activated feature.

Consequently a customer may be presented with relevant information related to specific products when the customer is in proximity of the products. This will ease the shopping experience for the customer as well as enable the shops to increase their sales.

In some embodiments the open retail space further comprises an approach-zone audio feature comprising: <ul id="ul0005" list-style="none" compact="compact"><li>● at least one sensor for detecting the position of a customer in the approach zone; and</li><li>● a processing unit for controlling functionalities of said approach zone audio system;</li></ul> wherein said at least one sensor is connected to said at least one processing unit and transmits a sensor signal to said processing unit, said processing unit being configured to process said sensor signal to determine the position of said customer and to control said at least one speaker based on the determined position of said customer.

In some embodiments, the approach zone audio feature is positioned inside an audio zone.

The approach zone may have any shape or size; in some embodiments the approach zone is positioned around a product towards which the shop wishes to direct the customer's attention. The sensor may be any kind of sensor suitable for detecting the position of a customer within a predefined zone such as an optical sensor e.g. a camera, an ultrasound sensor, or pressure sensors positioned in the floor. The processing unit may control the volume and type of audio signals played by the at least one speaker, so that a first approach-zone audio signal is played when the customer is in a first part of the zone, and a second approach-zone audio signal is played when the customer is in a second part of the zone. The processing unit may increase the volume when the customer moves close to the centre of the approach zone.

Consequently, customers may be guided towards specific goods or products, making their shopping experience more interesting.

In some embodiments, the first audio signal and the second audio signal are provided to the multitrack player from a streaming server positioned in another building than the open retail space.

Consequently, a service provider may operate multi-zone audio systems for a number of open retail spaces from a central location in an easy an effective manner.

In some embodiments, the at least one speaker of the first and second audio zones is a directional speaker.

The directivity index for the directional speakers measured at X kHz, may lie between 1.01 and 200.

The directivity index for the directional speakers measured at X kHz, may lie between 1.5 and 200.

The directivity index for the directional speakers measured at X kHz, may lie between 5.0 and 200.

The directivity index is defined as the ratio of the intensity of a speaker at a particular point along the acoustic axis of the speaker to the intensity at the same point in space from an omni-directional point source with the same acoustic power.

According to a second aspect, the disclosure relates to a method for designing audio signals for a multi-zone audio system for an open retail space, said audio system comprising a first audio zone and a second of audio zones for providing a first physical zone and a second physical zone with a first soundscape and a second soundscape, said open retail space comprising static noise sources resulting in a first static noise signal in said first audio zone and a second static noise signal in said second audio zone, said method comprising the steps of: <ul id="ul0006" list-style="none" compact="compact"><li>● measuring a spectral distribution of the first static noise signal and a spectral distribution of the second static noise signal;</li><li>● designing a first audio signal for said first audio zone having a spectral distribution adapted to perceptually mask the first static noise signal;</li><li>● designing a second audio signal for said second audio zone having a spectral composition adapted to perceptually mask the second static noise signal.</li></ul>

In some embodiments, the method further comprises the step of designing the first audio signal and the second audio signal as components of a combined audio signal.

Consequently, music signals can be designed that are adapted especially to mask static noise in open retail spaces. By designing the first audio signal and the second audio signal as components of a combined audio signal, the combination of the first and the second audio signals may complement each other, thereby creating pleasant transitions from one audio signal to another audio signal for a customer walking from a first audio zone into a second audio zone.

According to a third aspect, the disclosure relates to an audio system configured to provide an open retail space with a plurality of audio zones, said audio system comprising: <ul id="ul0007" list-style="none" compact="compact"><li>● a first audio zone and a second audio zone for providing a first physical zone and a second physical zone in the open retail space with a first soundscape and a second soundscape, each audio zone comprising at least one speaker, said open retail space comprising static noise sources resulting in a first static noise signal in said first audio zone and a second static noise signal in said second audio zone, wherein said first static noise signal and said second static noise signal have a respective specific frequency spectrum;</li><li>● a multitrack player for providing said at least one speaker of said first audio zone with a first audio signal and said at least one speakers of said second audio zone with a second audio signal; and</li></ul> wherein said first audio signal has a frequency spectrum configured to perceptually mask the first static noise signal and said second audio signal has a frequency spectrum configured to perceptually mask said second static noise signal.

According to a fourth aspect, the invention relates to an audio system configured to provide an open retail space with a plurality of audio zones, said audio system comprising: <ul id="ul0008" list-style="none" compact="compact"><li>● at least one first speaker, said open retail space comprising static noise sources resulting in a first static noise signal in said first audio zone and a second static noise signal in said second audio zone, wherein said first static noise signal and said second static noise signal have a respective specific frequency spectrum;</li><li>● a multitrack player for configured for replay of a first audio signal through said at least one first speaker and a second audio signal through said at least one second speaker; and</li></ul> wherein said first audio signal has a frequency spectrum configured to perceptually mask said first static noise signal and said second audio signal has a frequency spectrum configured to perceptually mask said second static noise signal.

Here and in the following, the terms 'processing means' and 'processing unit' are intended to comprise any circuit and/or device suitably adapted to perform the functions described herein. In particular, the above term comprises general purpose or proprietary programmable microprocessors, Digital Signal Processors (DSP), Application Specific Integrated Circuits (ASIC), Programmable Logic Arrays (PLA), Field Programmable Gate Arrays (FPGA), special purpose electronic circuits, etc., or a combination thereof.

The different aspects of the present invention can be implemented in different ways including the open retail spaces, methods for designing audio signals for a multi-zone audio system, and audio systems described above and in the following, each yielding one or more of the benefits and advantages described in connection with at least one of the aspects described above, and each having one or more preferred embodiments corresponding to the preferred embodiments described in connection with at least one of the aspects described above and/or disclosed in the dependent claims. Furthermore, it will be appreciated that embodiments described in connection with one of the aspects described herein may equally be applied to the other aspects.

<u>Brief description of the drawings</u>

The above and/or additional objects, features and advantages of the present invention will be further elucidated by the following illustrative and nonlimiting detailed description of embodiments of the present invention, with reference to the appended drawings, wherein: <ul id="ul0009" list-style="none" compact="compact"><li><figref idref="f0001 f0002">Figs 1a-b</figref> show schematic drawings of an open retail space comprising an audio system according to embodiments of the present invention,</li><li><figref idref="f0003">Figs 2a-f</figref> illustrate how the audio signals are configured to mask static noise signals in the audio zones according to an embodiment of the present invention,</li><li><figref idref="f0004">Fig. 3</figref> shows a motion-activated feature according to an embodiment of the present invention,</li><li><figref idref="f0004">Fig. 4</figref> shows a schematic drawing of a motion-activated feature according to an embodiment of the present invention,</li><li><figref idref="f0005">Fig. 5</figref> shows an approach-zone feature according to an embodiment of the present invention,</li><li><figref idref="f0005">Fig. 6</figref> shows a schematic drawing of approach-zone feature according to an embodiment of the present invention,</li><li><figref idref="f0006">Fig. 7</figref> shows a flowchart of a method for designing audio signals for a multi-zone audio system; and</li><li><figref idref="f0007">Fig. 8</figref> shows an open retail space according to an embodiment of the present invention.</li></ul>

Detailed description

In the following description, reference is made to the accompanying figures, which show by way of illustration how the invention may be practiced.

<figref idref="f0001">Figure 1a</figref> shows a schematic drawing of an open retail space comprising an audio system according to an embodiment of the present invention. The open retail space 102 is not divided by any walls; however, there may be a number of shelves or the like present creating corridors in the open retail space, e.g. supermarket shelves. The open retail space comprises a first audio zone 103, a second audio zone 104, a first microphone 115, a multi-track player 105 and a central processing unit 106. The first audio zone 103 has three speakers 107, 108, 109 associated therewith each being positioned at the periphery of the first audio zone 103 facing approximately towards the centre of the first audio zone. Correspondingly, the second audio zone 104 has three speakers 110, 111, 112 associated, each being positioned at the periphery of the second audio zone 104 facing approximately towards the centre of the second audio zone 104. The speakers may be fastened in a ceiling of the open retail space 102. The shape of the two audio zones 103, 104 is determined by the positioning of the speakers and their relative volume e.g. by turning up the volume of the speakers of the first audio zone 103 relative to the volume of the speakers of the second audio zone 104 the size of the first audio zone 103 will increase and the size of the second audio zone 104 will decrease.

<figref idref="f0002">Figure 1b</figref> shows a schematic drawing of an audio system according to an embodiment of the present invention. The audio system comprises a multi track player 106, a central processing unit 105, a first amplifier 114, a second amplifier 112, a first audio zone 103, a second audio zone 104, and a first microphone 115. Each audio zone further comprises three speakers 107, 108, 109, 110, 111, 112. The multi track player 106 provides a first audio signal to the first audio zone 103 and a second audio signal to the second audio zone 104. The audio signals are processed by the central processing unit 105, where filters may be applied. The central processing unit 105 is connected to the first and second amplifiers 114, 113 and transmits the first audio signal to the first amplifier 114 and the second audio signal to the second amplifier 113. The first amplifier is connected to the three speakers 107, 108, 109 of the first audio zone 103 and provides the speakers with the first audio signal, thereby providing the first audio signal to the first audio zone. The second amplifier 113 is connected to the three speakers 110, 111, 112 of the second audio zone 104 and provides the speakers 110, 111, 112 of the second audio zone 104 with the second audio signal, thereby providng the second audio signal to the second audio zone 104. The first and second amplifier 113, 114 respectively, may comprise a processing unit capable of filtering the audio signals. The first microphone 115 is connected to the central processing unit 105 and transmits a recorded signal indicative a total background noise to the central processing unit 105. The central processing unit 105 may be provided with signal processing algorithms making it possible to estimate the total background noise present in the open retail space 102. The central processing unit 105 may control the volume of the speakers based on a detected level of the total background noise.

<figref idref="f0003">Figures 2a-f</figref> illustrate how the audio signals are configured to mask static noise signals in the audio zones according to an embodiment of the present invention. <figref idref="f0003">Figure 2a</figref> shows an open retail space 201 comprising a first audio zone 202, a second audio zone 203, and five static noise sources 206, 207, 208, 209, 210. The static noise sources are noise sources having a frequency spectrum that is approximately static over a predetermined period of time, such as respective noise signals originating from a refrigerator, a freezer, or a ventilation system during operation of the compressors. Two static noise sources 206, 207 are positioned inside the first audio zone 202, two static noise sources 208, 209 are positioned inside the second audio zone 203, and one static noise source 210 is positioned outside the first and second audio zones. <figref idref="f0003">Figure 2b</figref> shows the frequency distribution of the five static noise sources 206, 207, 208, 209, 210. The static noise sources result in a spatial varying static noise field that can be measured as static noise signals. <figref idref="f0003">Figure 2c</figref> shows the frequency distribution of the static noise signal 204 measured in the centre of the first audio zone 202. The static noise sources 206, 207 that are close to the centre of the first audio zone contribute more than the static noise sources that are farther away 208, 209 210. Correspondingly, <figref idref="f0003">Figure 2d</figref> shows the frequency distribution of the static noise signal 205 measured in the centre of the second audio zone 203. The static noise sources that are close to the centre of the second audio zone 208, 209 contribute more than the static noise sources that are farther away 206, 207, 210. <figref idref="f0003">Figure 2e</figref> shows the frequency distribution of a first audio signal A1 configured to perceptually mask the static noise signal 204. The major part of the energy of the first audio signal A1 is within the same frequency interval as the major part of the energy of the first static noise signal 204. Consequently, by playing the first audio signal A1 in the first audio zone 202, an effective masking of the static noise in the first audio zone 202 is achieved. <figref idref="f0003">Figure 2f</figref> shows the frequency distribution of a second audio signal A2 configured to perceptually mask the static noise signal 205. The major part of the energy of the second audio signal A2 is within the same frequency interval as the major part of the energy of the second static noise signal 205. Consequently, by playing the second audio signal A2 in the second audio zone 203, an effective masking of the static noise in the second audio zone 203 is achieved.

<figref idref="f0004">Figure 3</figref> shows a motion-activated feature according to an embodiment of the present invention. The motion-activated feature 301 comprises a sensor 303 for detecting motion of a customer within a predetermined watch zone 302, a processing unit 304, and a speaker 305. The watch zone 302 may have a size and a shape securing that only one single customer is, most of the time, present in the watch zone 302. The size of the watch zone is determined by the type of sensor and the positioning of the sensor 303; e.g. if the sensor is a camera, the shape and size of the watch zone is determined by the viewing field of the camera; and when the sensor is pressure sensors arranged in the floor, the size and shape of the watch zone 302 is determined by the positioning of the pressure sensors. The speaker 303 is preferably arranged to face the watch zone 302, such that an audio signal played by the speaker 305 is audible to a customer in the watch zone 302. In some embodiments, a plurality of motion-activated features is present in the different audio zones.

<figref idref="f0004">Figure 4</figref> shows a schematic drawing of the motion-activated feature 401, according to an embodiment of the present invention. The motion-activated feature 402, comprises a sensor 402, a processing unit 403, and a speaker 404. The sensor 402 is connected to the processing unit 403 and transmits a signal indicative of any motion in the watch zone to the processing unit 403. The processing unit 403 processes the signal to determine if a customer is present in the watch zone. The processing unit may use an algorithm suitable for the task, depending on the type of sensor. The processing unit 403 is connected to speaker 404 and transmits a watch-zone specific audio signal to the speaker 404 when a customer is detected in the watch zone.

<figref idref="f0005">Figure 5</figref> shows an approach-zone feature according to an embodiment of the present invention. The approach-zone feature 501 comprises an approach zone 502 comprising a central item 506, a sensor 503, a processing unit 504, and a speaker 505. The size of the approach zone is determined by the type of sensor and the positioning of the sensor 503; e.g. if the sensor is a camera, the shape and size of the watch zone is determined by the viewing field of the camera; and when the sensor is pressure sensors arranged in the floor, the size and shape of the watch zone 502 is determined by the positioning of the pressure sensors. The speaker 503 is preferably arranged to face the approach zone 502 such that an audio signal played by the speaker 505 is audible to a customer in the approach zone 502. The central item 506 may be a product that the owner of the open retail space wishes the customer to notice. In some embodiments a plurality of approach-zone features are present in the different audio zones.

<figref idref="f0005">Figure 6</figref> shows a schematic drawing of an approach-zone feature according to an embodiment of the present invention. The approach-zone feature 601 comprises a sensor 602, a processing unit 603, and a speaker 604. The sensor 602 is arranged to detect the position of a customer in the approach zone. The sensor 602 is connected to the processing unit 603 and transmits a signal indicative of the position of a customer in the approach zone to the processing unit 603. The processing unit 603 may use an algorithm suitable for the task, depending on the type of sensor. The processing unit 603 is connected to the speaker 604 and controls the speaker based on the determined position of the customer. The processing unit 603 may control the speaker 604 in the following way: First the processing unit 603 monitors the approach zone to determine when a customer enters the approach zone. The processing unit 603 may control the speaker 604 to play a first approach-zone audio signal when there is no customer in the approach zone. Then, when the processing unit 603 detects that a customer enters the approach zone, the processing unit 603 may control the speaker 604 to play a second approach-zone audio signal. Then, when the processing unit 603 detects that the customer approaches the central item, the processing unit 603 may increase the volume of the speaker 604, so that the customer experiences an increase in loudness of the second approach-zone audio signal. Alternatively or additionally, when the processing unit 603 detects that the customer approaches the central item, the processing unit 603 may control the speaker 604 to play a third approach zone audio signal.

<figref idref="f0006">Figure 7</figref> shows a flowchart of a method for designing audio signal for a multi-zone audio system for an open retail space. In the first step 702, the spectral distribution of a first static noise signal is measured in a first audio zone. Then, in step 703, the spectral distribution of a second static noise signal is measured in a second zone audio zone. In step 704, a first audio signal is designed for the first audio zone, having a spectral distribution adapted to perceptually mask the first static noise signal. Then, finally, in step 705, a second audio signal is designed for the second audio zone, having a spectral distribution adapted to perceptually mask the second static noise signal.

<figref idref="f0007">Figure 8</figref> shows an open retails space according to an embodiment of the present invention. The open retail space 801 is in this embodiment a shop selling electronic products. The open retail space 801 comprises three audio zones 802, 803, 804. Each audio zone is created by a plurality of speakers (not shown). The speakers may be arranged in to ceiling of the open retail space 801. Each audio zone 802, 803, 804 is centred around a respective row 805, 806, 807 containing products e.g. electronic equipment. The soundscape provided in each audio zone, may be designed to complement the products on sale in the rows. In addition the open retail space 801 comprises a plurality of motion activated features 807a-t arranged at the rows positioned at the periphery of the open retail space 801. Each of the motion activated features 807a-t may comprise a directional speaker allowing a customer positioned in the watch zone of a particular motion activated feature to be presented with a sound identity of the products on sale in that part of the row. Similarly each of the rows in the audio zones 802 803 804 comprises a plurality of motion activated features 808a-j (only the motion activated features in the audio zone 802 has been numerated for simplicity). The shop comprising the open retail space is further provided with two motion activated features 809, 810 positioned at the entrance of the shop.

Although some embodiments have been described and shown in detail, the invention is not restricted to them, but may also be embodied in other ways within the scope of the subject matter defined in the following claims. In particular, it is to be understood that other embodiments may be utilised and structural and functional modifications may be made without departing from the scope of the present invention.

In device claims enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims or described in different embodiments does not indicate that a combination of these measures cannot be used to advantage.

It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.