WO2020249903A1

WO2020249903A1 - Sensory vibratory system

Info

Publication number: WO2020249903A1
Application number: PCT/FR2020/050992
Authority: WO
Inventors: Damien QUINTARD
Original assignee: Quintard Damien
Priority date: 2019-06-11
Filing date: 2020-06-11
Publication date: 2020-12-17
Also published as: FR3097362A1; FR3097362B1

Abstract

The invention relates to a sensory vibratory system comprising at least one transducer (1, 3) supplied with an electrical signal originating from a processing means for processing a sound signal. Said processing means transposes the frequencies higher than a threshold frequency F_SB of between 30 and 80 Hz by modifying the pitch of the audio signal without modifying the duration thereof, the spectral range of the processed signal being lower between 0 and 500 Hz, and preferably between 0 and 300 Hz.

Description

Sensory vibratory system

Field of the invention

The present invention relates to the field of accessibility of music by the deaf.

Deafness is a handicap that is little recognized and poorly accepted by outsiders because it is not necessarily visible. There are about 400,000 severely deaf in France who are often confronted with a lack of understanding and are quickly isolated. While people without disabilities are able to hear and distinguish high-pitched sounds, low-pitched sounds, spoken sounds, sung sounds and noises, the deaf can “hear” or feel vibrations from low-pitched sounds. Apart from people with cophosis (an uncommon trauma to the inner ear that makes deafness total), the low frequencies are audible by people with deafness. Therefore, they can hear the music but in a different way. Indeed, music is the sound that is felt the best, by people with hearing impairment or not.

The explanation lies in the fact that musical sounds require seventy times less brain work to process than simple words, and one hundred and fifty times less than simple noises. Thus, a partially deaf person is also able to appreciate music, especially since there are possibilities of assistance to improve the sensations caused by sound vibrations.

During musical events, certain devices make it possible, on a large scale, to increase the senses of the deaf. Some concert halls install vibrating floors that conduct low frequency vibrations. It is also possible to distribute somesthetic receptors that transmit tactile vibrations. Finally, baffles and loudspeakers, depending on their size and power, can modulate the perception of vibrations.

More recently, tactile transmission equipment has been developed in the form of a necklace, a bracelet and a brooch which, combined, "form an alternative sensory system translating the audio tracks into vibrations", known as name of Vibeat and connected by Bluetooth, it allows those who wear it to experience the songs with just a touch, or even a backpack called “Subpac” (trade name), which vibrates to the rhythm of the music.

State of the art

International patent application W02018 / 027168 describes a system providing tactile sensations. The system includes a seat back of a seat, the seat back having a left side and a right side separated by a center line of the seat back. A first plurality of electroactive transducers arranged along the center line of the seat back provide tactile sound to a user. A second plurality of electroactive transducers located in the seat back provide alerts or tactile feedback and include a left side electroactive transducer and a right side electroactive transducer at the left and right sides of the seat back, respectively. This solution consists in transmitting the low frequencies to make the equipped person perceive not the musical phrase but simply the rhythm of the music. This solution is in the form of backpacks known under the trade name “Subpac” loaned to spectators of a musical show who request it. They vibratively retransmit the low frequencies of any sound source, from all media (sound control, computer, smartphone, television), thanks to an assembly of transducers, vibro-tactile polymers and electronics.

Patent application WO9609617 also relates to a control system which reacts to an audio signal produced by an audio source, such as a computer, a video game console, a stereo system or the like to convert the audio signal into a signal from. order for a vibrating seat cushion or similar item. The processed signal is used to produce a control signal. The control signal causes the tactile sensation generator to produce a tactile sensation which is related to the scene appearing on a screen, for example the screen of a computer on which a video game is played.

The patent application US2012306631 describes a method executed by one or more processes running on computer systems comprises the reception of an audio signal comprising a range of audio frequencies comprising high and low frequencies, the conversion of a first part of haptically changing the audio frequency range of the data, by shifting a second part of the audio frequency range to a different range of audio frequencies, and presenting at least one of the converted first part and the shifted second part to a human user . Other implementations of this aspect include corresponding systems, apparatus, and computer program products.

Disadvantages of the prior art Certain solutions of the prior art are essentially aimed at transmitting the perception of the rhythm of the music by a haptic transmission synchronous with the temporal structure of the music (spacing, duration, accentuation of musical sounds), the intensity of the vibrations being the image the regular succession of strong beats and weak beats of the music.

These solutions are generally associated with the visual perception of the instrumentalists for hybrid accessibility to a show. For example, for a HipHop show, the presence of giant screens associated with vibrating backpacks make it possible to correlate the clearly visible gestures of the DJ perched on his platform, the play of light, the circular space created by the dancers and the excitations. tactile transmitted by the backpack.

These solutions make it possible to transmit musical emotions only very partially, in particular for musical compositions which do not have particular rhythmic characteristics.

Other solutions aim to provide information translating melodic aspects by haptically or visually localized information.

These solutions require complex learning to allow an association between the physical or visual localization of the excitation and the melodic line.

Solution provided by the invention

In order to respond to the drawbacks of the prior art, and in particular to provide better accessibility for the deaf to a musical experience and to participate in musical performances, the invention relates to its most acceptable meaning general sensory vibration comprising at least one transducer supplied by an electrical signal coming from a means for processing a sound signal characterized in that said processing means transposes the frequencies above a threshold frequency F _SB between 30 and 80 Hz, by modifying the pitch of the audio signal without modifying its duration, the spectral range of the processed signal being less between 0 and 500 Hz, and preferably between 0 and 300 Hz.

For the purposes of the present patent, “pitch of sound” or “pitch of audio signal” is understood to mean the frequency of the fundamental of a sound or audio signal in the Fourier decomposition of this signal. The higher the frequency of the fundamental, the higher the pitch will be and vice versa.

Transposition consists of shifting all the notes of an audio signal without changing timbre or speed, using suitable software.

In the solutions of the prior art, the processing consists in retaining the envelope of the sound signals and the variation in amplitude of this envelope, in order to control reproduction of the rhythms, and not the audio signals themselves.

On the contrary, the invention relates to a transposition of the fundamental frequency, namely the order 1 harmonic of the fourrier transform of the original audio signal in order to preserve the frequency dynamics after transposition to a lower frequency and to provide a transposed rich signal.

Advantageously, the system comprises two transducers, one of which receives said processed signal via a low-pass filter, and the other receives said processed signal via a high-pass filter. The invention notably comprises a sensory vibratory system comprising at least one transducer supplied with an electrical signal coming from a means for processing a sound signal, characterized in that it comprises a plurality of FPB _± bandpass filters having ranges consecutive frequencies [F _± , F _{1 + i} ] covering the entire sound spectrum,

Each of said band-pass filters FPB _± providing an output signal SP _± being the subject of a processing for the purpose of modifying the pitch of a sound signal without modifying its duration FT _± consisting in limiting the spectral range of the sound signal. output signal SS _± with respect to the spectral extent of the frequency range [F _± , F _{1 + i} ] of the signal SP _± Means for mixing said processed signals SS _{± in order} to reconstitute an electrical supply signal for said transducer.

Preferably, it comprises at least two transducers, each of said transducers receiving a specific spectral range of said signal produced by said mixing means.

According to a preferred embodiment, a plate supports the transducer or transducers, said plate being covered by sound insulation foam.

According to one variant, said plate supporting the transducer or transducers is covered on the outside with a layer of elastomer.

According to one variant, it comprises at least two loudspeakers offset vertically.

Preferably, the amplification level of the processed signal delivered to the upper loudspeaker is a function increasing by a frequency representative of said processed signal, and in that the amplification level of the processed signal delivered to the lower speaker is a decreasing function of a frequency representative of said processed signal. The invention also relates to a method of processing an audio signal in order to control at least one transducer of a sensory vibratory system, characterized in that a spectral separation is carried out to produce N signals SP _± corresponding to frequency ranges. [Fi, F _{1 + i} ] consecutive and covering the whole of the sound spectrum, to a processing consisting in modifying the pitch of a sound signal without modifying its duration, of the output signal SS _± with respect to the spectral range of the frequency range [F _± , Fi _{+ i} ] of the signal SP _±

to a mixing of said processed signals SS _{± in order} to reconstitute an electrical supply signal for said at least one transducer.

Preferably, a second band-pass filtering over the same range is also carried out for each of said signals SS _± in order to improve the quality Q factor.

Advantageously, low-pass filtering is also carried out for the supply of a first transducer and high-pass filtering for the supply of a second transducer.

According to a variant, the vibratory system also provides an original stereo stream comprising unprocessed sound information.

Detailed description of a non-limiting example of

The invention The present invention will be better understood on reading the detailed description of a non-limiting example of the invention which follows, with reference to the appended drawings where:

• Figure 1 shows a schematic view of a system according to the invention.

• FIG. 2 represents a block diagram of the processing of the audio signal.

Material Description

The system consists of a stand-alone block with a dimension of approximately 200x400 mm, and a thickness of 150 mm, which can be used as a backrest or a cushion. It comprises a rigid plate (10) 1 to 3 mm thick in plastic material, for example polycarbonate or PVC, on which two transducers (1, 3) are fixed. These transducers (1, 3) are surrounded by a sound foam (11), and covered at the rear by blocks of sound foam respectively (2, 4).

The outer surface may be covered with a layer of neoprene (12) to improve user comfort without sacrificing the feel of vibrations. This outer neoprene layer also contributes to a slight vibration damping to provide a soft but precise feeling.

The two transducers (1, 3) can be housed in a box sculpted to the shape and size of each transducer so as to be able to fit them inside. Their position is then fixed, and noise and parasitic vibrations are considerably reduced. It is made in three layers 10 mm thick: this technique allows easy sculpting and access to the transducers in case of repair. The first layer is glued to the vibrating surface. The other two are respectively screwed to the previous layer.

The first transducer (1) is intended for frequencies below a threshold value VTi of between 60 and 100 Hz, preferably 80 Hz.

The second transducer (3) is intended for frequencies in a higher band, preferably between the threshold value VTi of the first transducer (1) and an upper threshold value between 200 and 400 Hz, preferably 300 Hz. The system also comprises an electronic circuit

(5) with battery power, comprising a radiofrequency module, for example Bluetooth or WIFI, and an amplifier (400) delivering the excitation signals from the transducers (1, 3). A low pass filter (35) supplies the signals to the first transducer (1). A high pass filter (45) or band pass delivers the signals to the second transducer (3). The electronic components are placed on a 5mm layer of neoprene in order to cushion the impact of vibrations.

Processing of signals transmitted to the autonomous unit

The signals transmitted to the autonomous unit correspond to audio signals that have been the subject of specific processing, in real time or possibly recorded and broadcast synchronously with the audio signals.

The processing consists in breaking down the audio signal into N frequency ranges, with a module comprising band-pass filters. It comprises for example an equalizer (100) known in mixing studios separating the signals corresponding to consecutive frequency ranges to provide N channels, each corresponding to a frequency range. By way of example, the frequency bands are as follows:

0 to 50 Hz corresponding to the "sub-bass" range

50 to 200 Hz corresponding to the bass range

200 to 10 Khz corresponding to the message range (low-medium, medium and high)

10 kHz to 20 kHz corresponding to the range of intelligibility.

On the “sub-bass” channel, no modification of the signal is applied, except the possible application of a delay to allow resynchronization with the signals of the other frequency bands.

On the “bass” channel, a “pitch shift” type processing (110) is applied to modify the height of the sound signal in this frequency range, without modifying its duration. It can be streamed through the use of audio buffering, which creates latency. Such a processing of creating a timbre-shifted output signal from an input signal, with the following steps: receiving a digital representation of an input signal sampled at a first rate; resampling said digital representation of the input signal at a second rate which differs from said first rate; and - creating a digital representation of the timbre shifted output signal by periodically extracting a segment of the resampled input signal and reproducing the extracted segments at a rate equal to a fundamental frequency of the output signal, and output output signal timbre shifted at an output rate equal to said first rate.

The frequency range at the output of this processing is between 50 and 100 Hz. An additional processing (111) is also carried out to reduce the disturbances introduced by the harmonics resulting from the additional signals introduced to maintain the duration of the processed sequence. This processing consists of filtering by a 50-100 Hz bandpass filter and level limitation (compression).

Optionally, the range 50 to 100 Hz is subdivided into several intervals, for example three, each being the subject of a specific processing of the “pitch shift” type.

The signal in the range 200 Hz to 10 KHz is also the subject of a processing (120) of the "pitch shift" type to provide an output signal in a frequency range of 100 to 180 Hz, with a processing (121) by a band-pass filter to eliminate the harmonics resulting from the “pitch shift” process.

The signal with a frequency greater than 10 KHz is also the subject of a processing (130) of the "pitch shift" type to provide an output signal in a frequency range 180 to 200 Hz, with a processing (131) by a band-pass filter to eliminate harmonics resulting from the “pitch shift” process.

The channels are then added by a module (200), with a weighting of the level of each channel.

The channel recombination parameters are functions of music style. For this purpose, a memory (300) is intended for recording a table associating the styles of music with the weighting parameters of the spectral channels. A module (250) makes it possible to select the style of music being broadcast, in order to configure the recombination module (200). Optionally, the selection module (250) may include means for automatic recognition of the musical style, for example by software comparing a sample of music played with a base of acoustic prints recorded in a reference database.

Signal processing can be carried out by a dedicated software application of plug-in type providing the mixing functions (EQ - PITCH SHIFT - EQ2), or in the form of a dedicated electronic component.

Multi-speaker variant

According to a preferred example, the reproduction unit comprises at least one upper loudspeaker and one lower loudspeaker. It may optionally include additional loudspeakers to form a column of loudspeakers. The upper loudspeaker favors the high-pitched message and therefore the upper part of the processed signals.

The lower loudspeaker favors the low-pitched message and therefore the lower part of the processed signals.

To this end, the amplification level of the processed signal delivered to the upper loudspeaker is an increasing function of a frequency representative of said processed signal, and in that the amplification level of the processed signal delivered to the lower loudspeaker is a decreasing function of a frequency representative of said processed signal. The term "representative frequency" denotes, for example:

• The median frequency of the processed signal

• A frequency determined according to the nature of the instrument for executing the original signal, determined for example by an automatic recognition system or by manual input by a human operator or by an automatic recognition system of the nature of the signal. 'instrument and / or musical type, where appropriate by reference to a digital catalog.

One solution for setting the distribution of the processed signal between the upper loudspeakers and the lower loudspeaker consists in spectrally analyzing the original input signal to characterize the musical type and obtain the parameters for adapting the level of processing of the spectral ranges. in real time.

Alternatives

The system can of course also transcribe a normal audio stream. In this case, a part of the audio stream already codified by the processing is transmitted on the stereo stream A and the stereo stream B is used to send "normal" information to the system for possible listening through the headphones through the system.

Claims

1 - Sensory vibratory system comprising at least one transducer (1, 3) supplied with an electrical signal originating from a means for processing a sound signal, characterized in that said processing means transposes the frequencies above a threshold frequency F _SB between 30 and 80 Hz, by modifying the pitch of the audio signal without modifying its duration, the spectral range of the processed signal being less between 0 and 500 Hz, and preferably between 0 and 300 Hz.

2 - Sensory vibratory system according to claim 1 characterized in that it comprises two transducers (1, 3), one of which receives said processed signal via a low pass filter (35), and the other receives said processed signal through a high pass filter (45).

3 - Sensory vibratory system comprising at least one transducer (1, 3) supplied with an electrical signal originating from a means for processing a sound signal, characterized in that it comprises a plurality of FPB _± bandpass filters having consecutive frequency ranges [F _± , F _{1 + i} ] covering the entire sound spectrum,

Each of said band-pass filters FPB _± providing an output signal SP _± being the subject of a processing for the purpose of modifying the pitch of a sound signal without modifying its duration FT _± consisting in limiting the spectral range of the sound signal. output signal SS _± with respect to the spectral extent of the frequency range [F _± , F _{1 + i} ] of the signal SP _± Means for mixing said processed signals SS _{± in order} to reconstitute an electrical supply signal for said transducer. 4 - Sensory vibratory system according to claim 3 characterized in that it comprises at least two transducers (1, 3), each of said transducers receiving a specific spectral range of said signal produced by said mixing means.

5 - Sensory vibratory system according to any one of the preceding claims, characterized in that it comprises a plate (10) supporting the transducer or transducers (1, 3), covered by a sound insulation foam (11). 6 - Sensory vibratory system according to claim 5 characterized in that said plate (10) supporting the transducer or transducers (1, 3) is covered on the outside by an elastomer layer (12).

7 - Sensory vibratory system according to claim 1 characterized in that it comprises at least two speakers offset vertically.

8 - Sensory vibratory system according to claim 7 characterized in that the amplification level of the processed signal delivered to the upper speaker is an increasing function of a frequency representative of said processed signal, and in that the amplification level of the processed signal delivered to the lower speaker is a decreasing function of a frequency representative of said processed signal.

9 - Process for processing an audio signal to control at least one transducer of a sensory vibratory system, characterized in that a spectral separation is carried out to produce N signals SP _± corresponding to frequency ranges [Fi, F _{1 + i} ] consecutive and covering the entire sound spectrum, to a process consisting in modifying the pitch of a sound signal without modifying its duration, of the output signal SS _± with respect to the spectral extent of the frequency range [F _± , Fi _{+ i} ] of the signal SP _±

- To a mixing of said processed signals SS _{± in order} to reconstitute an electrical supply signal for said at least one transducer.

10 - A method of processing an audio signal to control at least one transducer of a sensory vibratory system according to claim 5 characterized in that one further proceeds, for each of said signals SS _± to a second band-pass filtering over the same range to improve the Q-factor of quality.

11 - A method of processing an audio signal for controlling at least one transducer of a sensory vibratory system according to claim 7 or 8, characterized in that one further proceeds to a low-pass filtering for the power supply. a first transducer and high pass filtering for powering a second transducer. 12 - A method of processing an audio signal to control at least one transducer of a sensory vibratory system according to at least one of claims 9 to 11 characterized in that the vibratory system also provides an original stereo stream comprising sound information untreated.