GB2537104A

GB2537104A - Device and method for simulating a blown instrument

Info

Publication number: GB2537104A
Application number: GB1505392.9A
Authority: GB
Inventors: Leslie Hayler Keith
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-03-30
Filing date: 2015-03-30
Publication date: 2016-10-12
Anticipated expiration: 2035-03-30
Also published as: GB2537104B; GB201505392D0

Abstract

A device 50 for simulating a blown musical instrument 12 such as a trumpet, saxophone, flute or horn includes: a mounting portion for connection to the instrument; a transmitting means configured to transmit a non-audible wave, such as an ultrasonic wave, inside the body of a blown instrument; and a receiving means configured to detect the waveform within the body of the instrument. The device is configured to output a signal, for example to a synthesiser 52, loudspeaker 56 or headphones 54, for simulating the performance and may be subject to processing such as filtering, equalisation, amplification, noise reduction, compression and modulation. The device may be used by a player, when practising, to provide a quieter output than would be achieved by playing the instrument naturally. The mounting portion may comprise a mouthpiece which replaces the original mouthpiece of the instrument, and may include a passage for expelling air blown into it by a user. A pressure sensor preferably detects movement of air within the passage. An independent claim defines a blown musical instrument with a hollow body, means for transmitting and receiving a non-audible wave within the body, and means for outputting a signal.

Description

Intellectual Property Office Application No. GII1505392.9 RTM Date:14 September 2015 The following terms are registered trade marks and should be read as such wherever they occur in this document: Bluetooth WiFi Intellectual Property Office is an operating name of the Patent Office www.gov.uk /ipo Title: Device and method for simulating a blown instrument

Description of Invention

The present invention relates to a device for simulating a blown instrument, and to a method for the same purpose. The invention relates in particular to a device for simulating woodwind instruments, or brass instruments. The invention also relates to an instrument configured to output a signal to a speaker or to a synthesiser.

Blown instruments such as woodwind and brass instruments produce acoustic sound waves at a particular frequency, or musical note, through acoustic resonance within the hollow body of the instrument. A user of the instrument (referred to as a musician or "player") excites acoustic resonance by blowing into a mouthpiece. Instruments such as oboes and clarinets, for example, have mouthpieces that include a flexible reed. Reed instruments focus air through the mouthpiece over a portion of the reed (or multiple reeds), causing the reed to vibrate. The vibration of the reed causes the air within the body of the instrument to vibrate. Other instruments, such as flutes for example, are played by directing a stream of air across an aperture defined at the mouthpiece. The edge of the mouthpiece separates the air stream, and a portion of the airstream acts on the air within the body of the instrument, causing that air to vibrate. Brass instruments (or "labrosones") provide mouthpieces against which the lips of a user vibrate when blowing. This vibration of the lips and mouthpiece causes air within the body to vibrate.

So, in general, the periodic oscillation of the player's lips, or the one or more flexible reeds, or air stream passing across an aperture, introduces acoustic energy into the air mass within the body. This energy contains frequency components occupying a wide bandwidth, in excess of the required range of output frequencies (or notes). The air mass exhibits a physical property known as acoustic impedance, which is the measure of opposition exhibited by the air mass to acoustic flow resulting from the acoustic pressure applied to the mass. The acoustic energy travels in the form of waves through the body, away from its source at the mouthpiece. Where the waves encounter a change in acoustic impedance, a portion of the waveform is reflected back towards the mouthpiece.

The required change in acoustic impedance is induced by the body being open 10 to the surrounding atmosphere, either by way of an aperture part way along the body, as in a woodwind instrument (see Figure 1), or by way of the body being open at its end (at the 'bell), as in a brass instrument (see Figure 2).

The reflected energy will subsequently encounter the mouthpiece and be reflected back into the body, where further reflection will occur as before. The interaction of multiple reflected waves across a broad range of frequencies induces resonant standing waves within the air mass thereby producing the required acoustic output at a single dominant frequency. The frequency of the resonance is determined by the physical distance from the mouthpiece to the opening that induced the change in acoustic impedance. The player varies the note produced by means of some form of hand-operated mechanism that alters this distance.

For a woodwind instrument, altering the distance between the acoustic impedance and the mouthpiece (i.e. selecting the required note) is achieved by opening a selected aperture of many defined along the extent of a fixed length body, by operating a key, or a combination of keys, associated with that aperture. For a brass instrument, this is achieved by using a key to open or close a valve, to introduce extra length(s) of tubing between the mouthpiece and the bell. In some brass instruments, an extendable slide is used to vary the effective length of the body. Continuous excitation by the player blowing into the instrument maintains resonance and hence sustains acoustic output.

Both woodwind and brass instruments are designed to produce sound at a significant volume, to be audible to an audience. A player may vary the volume of the instrument by causing more or less vibration of the air within the body of the instrument, according to how hard the instrument is blown. However, it is well known that many blown instruments either cannot be played quietly, or at least cannot be practised quietly in a way that mimics the blowing strength required to achieve a loud volume but without actually producing a loud noise. This is because the action of blowing into or across the mouthpiece, causing the air to vibrate within the body, causes audible sound waves that cannot easily be diminished or contained. Continuous excitation by the player blowing into the instrument maintains resonance and hence sustains acoustic output.

The volume of blown instruments can pose a problem where the player is unable to practise due to proximity of neighbours, for example, who may not wish to hear the instrument being played. This is particularly a problem where the player is inexperienced, and not yet able to produce a desirable tone. It may also be a problem where a musician wishes to practise in a densely populated residential area, such as in a block of flats or when residing in a hotel room.

According to an aspect of the invention we provide a device for simulating a blown instrument, the device including: a mounting portion for connection to a portion of the instrument, a transmitter configured to transmit a non-audible wave inside the body of the instrument; and a receiver configured to detect a waveform within the body of the instrument; wherein the device is configured to output a signal for simulating the sound of the instrument.

According to another aspect of the invention we provide a system for simulating a blown instrument, including: a device according to any one of claims 1 to 21; a synthesiser configured to receive an output signal from the device, and in response to the received signal to output an audio signal; and a loudspeaker configured to receive the audio signal from the synthesiser so as to make the audio signal audible.

According to another aspect of the invention we provide an instrument comprising: a substantially hollow body configured to generate a standing wave form in response to excitation of an air mass within the body; a transmitter configured to transmit a non-audible wave inside the body; and a receiver configured to detect a waveform within the body; wherein the instrument is configured to output a signal to a speaker or a synthesiser.

Further features of the various aspects of the invention are set out in the dependent claims appended hereto.

Embodiments of the invention are described herein, by way of example only, with reference to the following figures, in which: Figure 1 is a side view of a blown woodwind instrument; Figure 2 is a side view of a blown brass instrument; Figure 3 is a side view of a device according to embodiments of the invention mounted on a woodwind instrument; Figure 4 is a side view of a device according to embodiments of the invention mounted on a brass instrument; Figure 5 is a diagrammatic view of a system according to embodiments of the invention; Figure 6 is a diagrammatic view of a device according to embodiments of the invention; Figure 7 is a trace diagram produced by an oscilloscope, representing signal amplitude and passage of time, on the vertical and horizontal axes, respectively, in relation to the note lower G played on an alto saxophone; and Figure 8 is a trace diagram produced by an oscilloscope, representing signal amplitude and passage of time, on the vertical and horizontal axes, respectively, in relation to the note middle C# played on an alto saxophone.

With reference to Figures 1 and 2, known woodwind 10 and brass 110 instruments are now described. Where features are replicated between the two types of instrument, corresponding reference numbers are used to indicate similar parts, where a prefix '1' is added to those shown in relation to the brass instruments.

The figures show an instrument 10, 110 having a body 12, 112 and a mouthpiece 14, 114. The body 12, 112 provides a generally hollow elongate tube substantially enclosed by a wall 34, 134 along its length between a first end and a second end. A mass of air 28, 128 exists within the body 12, 112. The mouthpiece 14, 114 is formed at or adjacent the first end of the body 12, 112, the mouthpiece 14, 114 providing a mouthpiece inlet 22, 122 for a user to blow into (e.g. in the case of a clarinet or trumpet) or across (e.g. in the case of a flute). In the example shown in Figure 1, the body 12, 112 provides an opening 16, 116 at its second end (commonly referred to as a 'bell). The wall 34, 134 of the body 12, 112 may widen towards the opening 16, 116.

Alternatively, as is the case where a flute is concerned, the second end of the body 12, 112 may be closed by and end wall (not shown).

The instrument 10, 110 provides keys 24 for operation by a user, to enable the pitch of the sound produced by the instrument to be varied.

Where a woodwind instrument is concerned, as shown in Figure 1, operation of a key 24 causes a corresponding aperture (also referred to as a 'tone hole') to open (as shown at 26), controlled by a valve. By operating one or more keys 24, causing corresponding valves 26 to open the body 12 of the instrument to the atmosphere at those specific positions along the length of the body 12, changes in acoustic impedance are induced at those positions (indicated by numeral 30). A portion of the acoustic energy (i.e. waves) travelling from the mouthpiece 14 at the first end, along the body 12 towards its second end, encounters the change in impedance caused by the open valve 26, and is reflected back along the body 12 towards its first end. Further reflection of the wave occurs, within the body 12. The interaction of multiple reflected waves across a broad range of frequencies induces resonant standing waves within the air mass 28 thereby producing the required acoustic output at a single dominant frequency. The frequency of the resonance is determined by the physical distance Li from the first end of the body 12 (i.e. at or adjacent the mouthpiece 14) to the opening 26 that induced the change in acoustic impedance.

For a brass instrument, as shown in Figure 2, notes are generated in a similar manner. Operation of a key or other mechanism (not shown) results in a change in the length of the body 112, by opening and closing valves to introduce additional lengths of tubing to the passage between the mouthpiece 114 and the bell 116. In this way, the length of the passage between formed by the body 112 is varied (as indicated at 132). In the example of a trombone, the body 112 is formed with intersecting portions that slide one within the other, so that the length of the passage can be extended and contracted by moving the portions relative to one another.

Whichever instrument is played, a common feature of most brass and woodwind instruments is that the mouthpiece 14, 114 of the instrument is detachable from the body 12, 112 of the instrument. Typically, the mouthpiece provides a connecting portion 18, 118 adapted to be secured to a corresponding connecting portion 20, 120 formed at the first end of the body 12, 112 of the instrument. The portions may provide a screw thread, for example, so that the parts can be screwed together, such that the mouthpiece 14, 114 is held securely to the body 12, 112. The connecting portion 18, 118 of the mouthpiece may be adapted to fit around the corresponding portion of the body 20, 120 (as shown in Figure 1) or may be adapted to fit within the corresponding portion 20, 120 (as shown in Figure 2).

The mouthpiece 14, 114 provides a mouthpiece inlet 22, 122 for a user to blow into or across, so as to excite acoustic resonance of the air mass 28, 128 within the body 12, 112. This excitement is achieved as explained above, either by vibration of a reed and/or vibration of the portion forming the mouthpiece inlet 22, 122, and/or vibration of the lips of the player blowing into the mouthpiece 14, 114, and/or movement of the air at or within the mouthpiece caused by air blown by the player falling incident upon it.

With reference to Figures 3 to 6, a device 50, 150 for simulating a blown instrument is shown. The device 50,150 includes a mounting portion 42, 142 for connection to a portion of the instrument 12, 112. In embodiments, and as shown, the original mouthpiece 14, 114 of the instruments is removed and replaced by the device 50, 150. This results in an instrument formed with the body 12, 112 of the original instrument 10, 110, having a mouthpiece 36, 136 provided by the device 50, 150.

In other words, embodiments of the device 50, 150 are configured to replace the mouthpiece of an existing instrument, such that the mounting portion 42, 142 is configured to secure the device to the body 12, 112 of the instrument in place of a regular mouthpiece of the instrument when the regular mouthpiece is removed from the instrument. By 'regular mouthpiece', we mean the original mouthpiece of the instrument. In this way, the present invention allows a player to play an existing instrument, so as to simulate the sound of the original instrument using the device 50, 150.

The mounting portion 42, 142 is configured to secure the device to a corresponding formation 20, 120 of the instrument 12, 112, provided at the first end of the body 12, 112. In embodiments, the mounting formation 42, 142 provides a threaded portion configured to secure the device 50, 150 to a corresponding threaded formation of the instrument.

In embodiments, the device 50, 150 provides a mouthpiece inlet 38, 138 configured for a user to blow into or across. In embodiments, the device 50, may include one or more flexible reeds, of the type used in woodwind instruments. The inclusion of a reed may make the mouthpiece formed by the device feel more realistic, allowing the player to recreate the technique they would use when blowing into the original instrument. In addition, the mouthpiece inlet 38, 138 of the device may be shaped in the manner of the mouthpiece of a woodwind or brass instrument, so as to resemble the original mouthpiece of the instrument. A variety of stylings may be provided, so that a user may select an appropriate device resembling the instrument to which the device is to be connected. In this way, a user may substantially recreate the original appearance of the instrument by replacing the mouthpiece of the original instrument with a similarly styled device resembling that mouthpiece.

In embodiments, the device 50, 150 includes a sensor configured to detect movement of air at or adjacent the mouthpiece inlet 38, 138. The sensor may be a pressure sensor, for example, as is known in the art. The sensor provides information to the device 50, 150 about the manner in which the user is blowing. The information may include information relating to the expected volume of the instrument, based on the volume or pressure of air being blown, information about the direction of movement of the air blown, or any other relevant information.

In embodiments, the device 50, 150 defines a passage between the mouthpiece inlet 38, 138 and an outlet 44, 144 for expelling air blown into the mouthpiece inlet 38, 138 by a user. When air is blown into the mouthpiece inlet 38, 138, it passes through the passage within the device 50, 150, and exits the device via the outlet 44, 144, so that substantially none of the air passes from the device 50, 150 into the body 12, 112 of the instrument. In this manner, the air blown by the user causes no significant vibration of air within the body 12, 112. In such embodiments, a sensor 46, 146 may be included, configured to detect movement of air within the passage. This sensor 46, 146 may be used instead of, or in addition to, a sensor located at or adjacent the mouthpiece inlet 38, 138. In embodiments, the location of the outlet 44, 144 on the device 50, 150 is such that air blown into the mouthpiece inlet 38, 138 is expelled to atmosphere from the outlet 44, 144. In some embodiments, the or another sensor may be configured to detect movement of air at the outlet 44, 144. In embodiments, the airflow sensor 46, 146 senses both the presence and volume of airflow, passing over, towards, or through the sensor 46, 146, allowing the volume and tonal quality of the synthesised sound to emulate that produced when the instrument is played normally with differing strengths of breathing.

In other embodiments, rather than replacing a mouthpiece of an instrument, a device according the invention may be located on another part of the instrument, such as at or adjacent the bell 16, 116 of the body 12, 112. Alternatively, the device could be located within the passage defined by the body 12, 112, at or adjacent the first end of the body 12, 112. In such configurations, the device would not act as a mouthpiece, and the original mouthpiece may be retained. In such configurations, which are not shown in the drawings, the mounting portion is adapted to secure the device within the body, or adjacent an end of the body (i.e. either adjacent the bell 16, 116, or adjacent the first end).

The device 50, 150 provides a transmitter 64 configured to transmit a non-audible wave inside the body 12, 112 of the instrument. The transmitter 64 is disposed on a portion of the device 50, 150 configured to lie within the body 12, 112 of the instrument when the device 50, 150 is connected to the body 12, 112. In this manner, when the device 50, 150 is secured to the body 12, 112 using the mounting portion 42, 142, the transmitter is disposed at or adjacent the first end of the body 12, 112.

The device 50, 150 also provides a receiver 66 configured to detect a waveform within the body 12, 112 of the instrument. The receiver 66 is configured to receive a waveform reflected in response to waves transmitted by the transmitter. In particular, the receiver 66 is configured to detect a signal of the amplitude of the acoustic energy within the body 12, 112.

In other words, the transmitter transmits a signal within the body 12, 112 of the instrument, which sends a waveform along the length of the body 12, 112 towards its second end (as explained above in relation to the standard instruments). A change in acoustic impedance causes reflection of a waveform back towards the first end of the body 12, 112, at a length L2 along the length of the body 12, 112. This results in multiple reflected waveforms being formed within the air mass 28, 128. At any point within the body (or directly adjacent the body) the amplitude of the acoustic energy varies in time as the various waves interact with each other, adding or cancelling according to their phase. The phase of each wave is determined by the total distance that it has travelled since it was generated, and is therefore proportional to the length L2. Therefore each unique configuration of the instrument, and appropriate length [2, specific to the production of a particular musical note, produces a unique and characteristic variation of ultrasonic amplitude with time. In this sense the receiver 66 is configured to detect a signal of the amplitude of the acoustic energy within the body 12, 112.

The wave transmitted by the transmitter 64 is a non-audible wave. Preferably, the waves transmitted are ultrasonic waves. Since the transmitted waves are not audible, the waves created within the body 12, 112 of the instrument are also at frequencies that are not audible. Therefore, although effectively the instrument is being "played", no (or substantially no) audible sound is made by those waves. However, the wave frequencies can be received, measured, recorded, manipulated and transmitted, so that the output from the device 50, 150 may recreate the performance, and sound, of the original instrument. Albeit, the device 50, 150 allows the sound to be recreated at the same pitch as would have been generated by the original instrument, or at a different pitch, and at the same or a different volume.

In embodiments, the receiver 66 is disposed adjacent the transmitter 64, within the body 12, 112 of the instrument, at or adjacent the first end of the body 12, 112. In embodiments, the transmitter 64 and the receiver 66 are component parts of a transceiver, as shall be referred to herein. It should be understood that references to a 'transceiver' are also intended to include the use of a separate transmitter and receiver. Alternatively, in other embodiments the receiver 66 may be located at another position within, or close to, the body 12, 112. The transceiver is a transducer that is operable both to transmit and receive signals.

In more detail, the amplitude of the acoustic energy at any point in the body 12, 112 varies in time as the waves interact with each other, adding or cancelling according to their phase. The phase of each wave is determined by the total distance that it has travelled since it was generated. Therefore each unique configuration of the instrument, and appropriate length L2, specific to the production of a particular musical note, produces a unique and characteristic variation of ultrasonic amplitude with time. The duration of the transmitted pulse of energy is governed such that energy generation has ceased prior to the incidence of reflected energy at the receiver 66. This allows the device 50, 150 to be reconfigured to use the transceiver to detect ultrasonic energy from that point in time.

In operation, the reflected signals within the body 12, 112 are detected by the receiver 66 and the variation of signal amplitude over time is measured and stored temporarily in the memory device. After a period of time the process is repeated to determine whether the instrument has been re-configured by the player -in other words, whether the player has chosen to play a different note. This cycle is the repeatedly performed, providing periodic measurement of the configuration of the instrument. As previously described, each configuration of the instrument, relating to production of a particular musical note, produces a unique pattern of signal amplitude with time due to the difference in length L2.

The device 50, 150 provides an output port 60 for outputting an output signal, for simulating the sound of the instrument. In embodiments, the output signal corresponds to the detected waveform. In embodiments, the output port 60 comprises a wireless communication device for transmitting the output signal to a remote device, such as a remote speaker, a remote recording device, or a remote synthesiser, for example. The wireless communication device may communicate via Bluetooth, WiFi, infrared, or any other suitable wireless technology.

The body 12, 112 of the instrument typically provides an aperture at its first end, through which air blown by a player passes from the mouthpiece 14, 114.

Where the device 50, 150 is connected to the body 12, 112 of the instrument, the transceiver forms part of an end portion 40, 140 of the device 50, 150 that lies adjacent the aperture in the body. When the device 50, 150 is secured to the body 12, 112 of the instrument, the end portion 40, 140 substantially seals the aperture, so that little or no air passes from the mouthpiece body 36, 136 into the body 12, 1 1 2 of the instrument.

Figure 7 shows a trace produced by an oscilloscope where the vertical axis represents signal amplitude and the horizontal axis represents the passage of time from left to right (the axes are labelled with scale units accordingly). The trace corresponds to measurements taken for the note lower G played on an alto saxophone. The large signal peaks, exceeding the vertical screen limits at the left and right of the trace, show successive excitation pulses generated by the transducer. The middle portion of the trace (centred within the display for clarity) shows the variation of signal amplitude received by the receiver between periods of excitation. Similarly, Figure 8 corresponds to measurements taken for the note middle C# played on an alto saxophone.

The device 50, 150 includes electronic circuitry connecting the transceiver and the output port 60. In embodiments, the device 50, 150 includes a processing unit 62 (i.e. including a processor, and may also include a memory). On receipt of a signal, the receiver 66 is adapted to generate a first signal corresponding to the detected waveform, and the processing unit 62 is configured to process the first signal and generate a second signal. The signal output by the output port corresponds to the second signal. In embodiments, the processing unit 62 is configured to digitise the first signal (i.e. to output a second signal that is a digitised version of the first signal). The processing unit 62 may include circuitry configured to process the first signal by applying at least one of: enveloping, compression, amplification, equalisation, filtering, noise reduction, noise cancelling, and modulation. The output signal may be a digital audio signal or an analogue audio signal, or may be a MIDI signal.

In embodiments, at the end of each measurement period the pattern that has been temporarily stored is compared to a set of reference values retrieved from electronic memory to determine which of the multiple possible instrument configurations is prevalent. Each type of instrument requires a different set of reference values. So as to allow for small differences between instruments, this set of reference values can be derived from a training sequence, where the player is requested to operate a pre-determined sequence of key permutations, the results for each of which are stored in electronic memory. The storage of these predetermined results may be made in the memory within the device. Alternatively, or additionally, depending upon performance requirements, the stored values can be refined as the unit is employed in normal use, since there are only a discrete number of valid permutations that are possible. By on-going statistical analysis of the measured value sets the performance of the detection algorithm can be refined to produce an optimised performance characteristic. This evaluation, storing, and refreshing of stored values may be performed by the processing unit 62.

In other words, the processing unit 62 is configured to compare the received first signal to at least one of a predetermined set of reference values to determine a characteristic of the first signal. The predetermined set of reference values are stored in a memory, which may form part of the processing unit 62. The memory may be programmable by the player (through a calibration sequence, for example) to write reference values to the predetermined set of reference values. This includes the ability to overwrite existing values.

The processing unit 62 may store multiple sets of reference values. Each set may comprise a plurality of values, each value representing a characteristic of a signal, and each set comprising values associated with a specific instrument or family of instruments. For example, a set may relate to a B flat clarinet. For a specific pitch of note, played by that clarinet, the set may comprise one or more values, each representing a characteristic of a signal that corresponds to the specific pitch of note being played on the B flat clarinet. In other words, the values within that set relate to configurations of keys of the clarinet being depressed. Values of the characteristics that may be stored as reference values include, but are not limited to, the rate of change of amplitude with time, size of amplitude peaks, position of amplitude peaks (e.g. plotted against time), size of amplitude troughs and position of amplitude troughs (e.g. plotted against time).

The comparison of the reference values to the characteristics of the data received as the first signal, from the receiver, is performed using an algorithm. In order to perform classification of an observed signal pattern, analysis of 'n' characteristics of that pattern may be performed by considering the values of those n characteristics as data points in an n dimensional space, for example.

Algorithms for comparison of this nature are well known, and may include nearest neighbour classification, Bayes classifiers, linear classifiers, kernel methods, or the like.

In embodiments of the invention, the functionality of the processing unit 62 may be performed externally of the device 50, 150. In other words, the signal output from the device 50, 150 may be communicated to an external device such as a computer (e.g. a PC, laptop, tablet, smartphone, or the like), a synthesiser, or any other suitable device. That external device may comprise a processor and a memory, suitable for performing the functions of he processing unit 62, to obtain a suitable output signal for communication to a speaker, or to a synthesiser, or a recording device, as required.

The effective length L1 of the body 12, 112 of the instrument, between the location of a particular aperture and the mouthpiece 14, 114, and the effective length L2 between that key and the first end of the body 12, 112 when the device 50, 150 is attached to the body 12, 112, may be different. Therefore, the properties of the waves generated within the body of the original instrument 10, 110, and the body of the instrument when the device 50, 150 is in use, may be substantially different. Of course, using the predefined reference values, the processing unit 62 is able to determine which configuration of apertures is open when the player performs, and therefore is able to determine what note would be played by the instrument in its original configuration. This enables the device 50, 150, according to embodiments of the invention, to output a signal representing the pitch of the note that the player intends to play. In this way, the device essentially allows the player to operate their familiar instrument in a manner essentially similar to normal playing but without it producing audible output within the surrounding environs.

The device 50, 150 may be used in combination with a loudspeaker 56, so that the loudspeaker 56 produces a sound generated by the device 50, 150 in combination with the body 12, 112 of the instrument. In this case, the output signal of the device is an audio signal, and the loudspeaker 56 is connected to the output port 62 of the device 50, 150. The connection may be made by way of a standard audio lead 58, for example, or may be communicated wirelessly. The loudspeaker 56 makes the received audio signal audible to a user.

The loudspeaker 56, or the device 50, 150, may include a volume control setting which may be manually adjustable by the player, to control the volume of the output sound. In this way, a player may reduce the volume to a volume below that typically achieved by playing the original instrument. This allows a player to play an instrument as though it were to play loudly, but using the device 50, 150, the instrument itself is substantially silent. The output signal can be amplified to the required volume level, so as to limit the volume achieved. This means that intended loud passages of music can be practised and performed at lower volume, so that the blowing strength, and other actions of the performer, can be rehearsed without the instrument being played at a loud volume. The loudspeaker may, of course, form part of a pair of headphones 54, as illustrated. The term 'headphones' is intended to include ear pieces, earphones, and any other personal audio equipment of that nature.

The device 50, 150 may also be used in combination with a recording device, wherein the recording device is connectable to the output port 60 of the device 50, 150. The recording device may be configured to receive an output signal transmitted by the device (by wireless transmission, for example), or may be connected via a wired connection. The recording device may be used to record data indicative of the performance of the blown instrument, which may be in any format -an audio wave, a MIDI data file, or in any other data format.

The device 50, 150 may also be used in combination with a synthesiser 52. The synthesiser 52 may be connected to the device 50, 150 directly (e.g. via a cable 58). The synthesiser 52 may output a signal to headphones 54, or to another loudspeaker 56, or a recording device (not shown), or to any other device. The synthesiser 52 is configured to receive an output signal from the device 50, 150, and in response to the received signal to output one of a digital audio signal, an analogue audio signal, and a MIDI signal.

In embodiments, the device 50, 150 may not include its own processing unit 62, for example, and may output the signal received by the receiver 66 directly via the output port 60 to a separate synthesiser, or the like. The synthesiser 52 may process the received signal by applying at least one of: enveloping, compression, amplification, equalisation, filtering, noise reduction, noise cancelling, and modulation, or any other forms of audio manipulation as is generally known in the art.

In embodiments, a device according to the invention may be formed as part of an instrument. In that case, it is not necessary to disassemble any part of the instrument in order to secure the device -rather, the mouthpiece of the instrument is provided by the device. The instrument includes a substantially hollow body configured to generate a standing wave form in response to excitation of an air mass within the body, a transmitter configured to transmit a non-audible wave inside the body; and a receiver configured to detect a waveform within the body. Such an instrument is configured to output a signal to a speaker or a synthesiser, for example. The speaker may be formed on the body of the instrument, in some embodiments. An instrument with the configuration set out above may include any of the features previously set out in relation to the separate device 50, 150 provided for attachment to the body of an instrument, either individually or in any combination.

With reference to Figure 5 in particular, we now describe a specific example of the use of the device 50 of the present invention. The instrument used in this examples is a saxophone. The mouthpiece of the saxophone is replaced by a device providing a mouthpiece body of similar shape and dimensions to the original mouthpiece. The mouthpiece of a saxophone is routinely removed for cleaning and storage so this operation requires no modification to the body 12 of the instrument or any new or unfamiliar process to be undertaken by the user. The same is true for all blown instruments, generally.

The device 50 makes an airtight fit to the body of the instrument, using the same sealing mechanism as the conventional mouthpiece. The device 50 provides a mouthpiece inlet 38 into which the player blows to activate the device 50. This inlet 38 is made to emulate that of a conventional saxophone mouthpiece to replicate the normal playing process as closely as possible.

The air that is blown into this inlet 38 passes through or over an airflow sensor 46 before being exhausted into the atmosphere without entering the instrument body 12. The airflow sensor 46 senses both the presence and volume of airflow, allowing the volume and tonal quality of the synthesised sound to emulate that produced when the instrument is played normally with differing strengths of breathing.

In the case of an alto saxophone the keyed opening of the instrument body (i.e. an opening that is opened and closed to produce different musical notes, also known as a tone-hole) that is furthest from the mouthpiece is the Bb tone-hole. This is around 0.7m from the mouthpiece opening. Hence, any reflection of ultrasound energy caused by this opening will take approximately 4ms to arrive back at the transceiver. This figure is calculated assuming a speed of sound of 340m/s and is used as the basis for derivation of the repetition cycle duration.

An example transceiver that may be used, in embodiments, is one that is commonly and readily available as it is employed widely in reversing warning systems in vehicles. It operates at a nominal frequency of 40kHz. The transceiver is excited into resonant oscillation by subjecting it to 8 voltage pulses with a cyclic period of 25ps (the reciprocal of 40kHz), which equates to a total excitation period of 0.2ms. This causes the piezo-electric transceiver to ring' resonantly (in a manner analogous to striking a bell) for approximately 1 ms. A decaying output of the resonant transceiver is shown in Fig. 7, for example. After 1 ms the transceiver acts as a receiver for a further 4ms. This value is therefore sufficient to detect the opening of the B flat tone-hole (i.e. the aperture on the body 12 of the instrument, that when opened during normal performance, produces the pitch B flat. The whole timing cycle therefore occurs at a frequency of 200Hz, the reciprocal of (1+4)ms. The particularly darkened area of scope trace of Figure 7 is the group of excitation pulses for the next cycle of measurement.

The timing of the measurement period, and hence repetition frequency, is scaled such that it represents the minimum required for the instrument in question. This ensures that the response time between the player undertaking an action and an audible output being produced will equal, or be less than, the equivalent time when the instrument is being played audibly. This is because, by definition, at least one 'round trip' of acoustic energy is required to establish audible resonance. The same conditions thus prevail in the case of both audible and ultrasonic excitation.

For the purpose of illustration it is assumed that the player initially plays the note C#, which is that produced when all keys on the instrument are in their rest, or non-operated, position. In this condition the first open tone-hole is approximately 25cm from the transceiver and produces the characteristic variation of amplitude with time, as shown in Fig 8 of the drawings. The player then depresses three keys, appropriate to the production of the note G. This closes a number of tone-holes such that the first open one is now approximately 48cm from the transceiver, producing a larger delay and different variation of amplitude with time, as shown in Fig 7. Comparison of the two oscilloscope traces can be made (all values in the following comparisons are approximate and for illustration only); - In the case of the note C#; a trough value of 10mV is evident at 1.5ms, a peak value of 85mV at 1.8ms, a trough of 30mV at 2.2ms, and a peak of 75mV at 2.6ms.

In the case of the note G; a trough value of 10mV is evident at 1.5ms, a peak of 90mV at 1.8ms, a trough of 10mV at 2.2ms, and a peak of 55mV at 20 2.4ms.

It is clear from this non-exhaustive example that large data-sets for electronic comparison, allowing reliable identification of different configurations, can be readily derived by relatively simple analysis of the received signal, implying computational effort easily within the accepted performance range of current processor technologies.

As each unique permutation of openings, by definition, is associated with a particular note, then each of these permutations produces a unique variation of ultrasound amplitude with frequency. In the case of an alto saxophone there are two further holes that, in exclusive combination (i.e. they are never open simultaneously), govern the octave in which the note is produced. Each of these holes form a body opening, in the same manner as a tone-hole, and their operation is detected by the same physical mechanism as described above.

In embodiments, the device 50, 150 and system may provide an audible acoustic output of a varied nature in a performance scenario such that the player makes sounds different from those characteristically produced by the instrument. This may be used to provide artistic enhancement to the performance.

The device 50, 150 may be used to provide automated measurement of the physical characteristics of the body 12, 112 of an instrument during manufacture or repair. Instrument parts must undergo rigorous (and often lengthy) testing to ensure that they perform to the correct specification.

Defects in the body of the instrument may result in imperfect sound quality, incorrect tonality, and other issues. By using the device of the present invention, an automated measurement may be taken by generating a signal of known amplitude, for example, to create an output which can be measured against a known benchmark.

The device 50, 150 may further be used to a compare results obtained using a first instrument body against results obtained using a second instrument body (or against a template or reference data set) so as to compare instruments against each other, or against predetermined standards.

It should be understood that the features of the described embodiments are suitable to be combined in any combination, unless specifically stated otherwise.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS1. A device for simulating a blown instrument, the device including: a mounting portion for connection to a portion of the instrument, a transmitter configured to transmit a non-audible wave inside the body of the instrument; and a receiver configured to detect a waveform within the body of the instrument; wherein the device is configured to output a signal for simulating the sound of the instrument.
2. A device according to claim 1 wherein the receiver is configured to receive a waveform reflected in response to waves transmitted by the transmitter.
3. A device according to claim 1 or claim 2, wherein the receiver is configured to detect the amplitude of the acoustic energy formed within the body of the instrument.
4. A device according to any preceding claim, wherein the non-audible wave is an ultrasonic wave.
5. A device according to any preceding claim wherein the transmitter and the receiver are component parts of a transceiver.
6. A device according to any preceding claim wherein the output signal corresponds to the detected waveform.
7. A device according to any preceding claim, further including a processing unit, wherein the receiver is adapted to generate a first signal corresponding to the detected waveform, and the processing unit is configured to process the first signal and generate a second signal, wherein the output signal corresponds to the second signal.
8. A device according to claim 7, wherein the processing unit is configured to digitise the first signal.
9. A device according to claim 7 or claim 8, wherein the processing unit is configured to process the first signal by applying at least one of: enveloping, compression, amplification, equalisation, filtering, noise reduction, noise cancelling, modulation.
10. A device according to any one of claims 7 to 9, wherein the processing unit is configured to compare the received first signal to at least one of a predetermined set of reference values to determine a characteristic of the first signal.
11. A device according to claim 10, wherein the predetermined set of reference values are stored in a memory.
12. A device according to claim 10 or claim 11, wherein the determined characteristic of the first signal is indicative of the configuration of the body of the instrument.
13. A device according to any preceding claim, wherein the output signal includes at least one of: a digital audio signal, an analogue audio signal, and a MIDI signal.
14. A device according to any preceding claim, further comprising an output port for outputting the output signal.
15. A device according to claim 14, wherein the output port comprises a wireless communication device for transmitting the output signal.
16. A device according to any preceding claim, wherein the mounting portion is configured to secure the device to a corresponding formation of the instrument.
17. A device according to claim 16, wherein the mounting formation provides a threaded portion configured to secure the device to a corresponding threaded formation of the instrument.
18. A device according to any preceding claim, wherein the device is configured to replace the mouthpiece of the instrument, such that the mounting portion is configured to secure the device to the body of the instrument in place of a regular mouthpiece of the instrument when the regular mouthpiece is removed from the instrument.
19. A device according to any preceding claim, further including a mouthpiece inlet configured for a user to blow into or across.
20. A device according to claim 19, further including a sensor configured to detect movement of air at or adjacent the mouthpiece inlet.
21. A device according to claim 19 or claim 20, wherein the device defines a passage between the mouthpiece inlet and an outlet for expelling air blown into the mouthpiece inlet by a user.
22. A device according to claim 19, wherein the device defines a passage between the mouthpiece inlet and an outlet for expelling air blown into the mouthpiece inlet by a user, and further including a sensor configured to detect movement of air within the passage.
23. A device according to claim 21 or claim 22, wherein the location of the outlet on the device is such that air blown into the mouthpiece inlet is expelled to atmosphere from the outlet.
24. A device according to claim 19, wherein the device defines a passage between the mouthpiece inlet and an outlet for expelling air blown into the mouthpiece inlet by a user, the location of the outlet being such that air blown into the mouthpiece inlet is expelled to atmosphere from the outlet, and the device further including a sensor configured to detect movement of air at the outlet.
25. A combination of a loudspeaker and a device for simulating the sound of a blown instrument as defined according to any one of the preceding claims, wherein the output signal of the device is an audio signal and wherein the loudspeaker is connectable to the output port of the device so as to make the audio signal audible.
26. The combination of claim 25, wherein a pair of headphones comprises the loudspeaker.
27. A combination of a recording device and a device for simulating a blown instrument as defined according to any one of claims 1 to 24, wherein the recording device is connectable to the output port of the device, or is configured to receive an output signal transmitted by the device, so as to record data indicative of the performance of the blown instrument.
28. A combination of a synthesiser and a device for simulating a blown instrument as defined according to any one of claims 1 to 24, wherein the synthesiser is configured to receive an output signal from the device, and in response to the received signal to output one of a digital audio signal, an analogue audio signal, and a MIDI signal.
29. A system for simulating a blown instrument, including: a device according to any one of claims 1 to 24; a synthesiser configured to receive an output signal from the device, and in response to the received signal to output an audio signal; and a loudspeaker configured to receive the audio signal from the synthesiser so as to make the audio signal audible.
30. A combination of a blown instrument and a device according to any one of claims 1 to 24.
31. An instrument comprising: a substantially hollow body configured to generate a standing wave form in response to excitation of an air mass within the body; a transmitter configured to transmit a non-audible wave inside the body; and a receiver configured to detect a waveform within the body; wherein the instrument is configured to output a signal to a speaker or a synthesiser.
32. A device substantially as described herein and/or as shown in the accompanying drawings.
33. A system substantially as described herein and/or as shown in the accompanying drawings.
34. An instrument substantially as described herein and/or as shown in the accompanying drawings.
35. Any novel feature or novel combination of features substantially as described herein and/or as shown in the accompanying drawings.