WO2011102744A1

WO2011102744A1 - Dual theremin controlled drum synthesiser

Info

Publication number: WO2011102744A1
Application number: PCT/PL2011/000018
Authority: WO
Inventors: Jakub Tomasz Ciupinski
Original assignee: Jakub Tomasz Ciupinski
Priority date: 2010-02-22
Filing date: 2011-02-21
Publication date: 2011-08-25
Also published as: PL390519A1

Abstract

The electronic musical instrument fitted with the movement sensors connected to the computer, as two theremins (3, 4) of different frequency of oscillators. The central antennas (1, 2) of theremins (3, 4) are placed no further than 10 cm from each other. The instrument is fitted with the analog-to-digital converter, the microprocessor, the user interface, preferably all as elements of the laptop (5), the speakers (7, 8), the amplifier (9), and/or the mixer (10).

Description

DUAL THEREMIN CONTROLLED DRUM SYNTHESISER

Invention relates to the electronic musical instrument fitted with two theremins and used to generate multi-track electronic music with gestures.

There are known various electronic musical instruments fitted with external controllers or sensors enable musicians to intuitively perform music with gestures. Those controllers and/or sensors which enable musicians to convert movements of hands into sound are sometimes theremins. A theremin is a musical instrument from a group of electromechanical electrophones invented by Lew Teremen in twenties in 20th century. Sounds produced by a theremin remind a whistle, a saw or a violin. Sounds are extracted from the instrument by movement of the player's hand within two antennas, one of which controls the volume while the other controls the pitch.

It is known from the Japanese patent application number JP2005037758 a digital theremin which includes infrared camera which photographs the hand of a player. In these solution, the processing system receives a video signal from the camera and determines a frequency according to the detected size of player's hand, what enable to generate appropriate sound corresponding to the appropriate frequency. The sound is transmitted to the audio amplifier and it is issued by the speaker. The generated signal respects the principle according to which the size of the hand is reversely proportional to the square of the distance between camera and hand.

It is known from the Japanese patent application number JP2004086118 the theremin acting on the basis of sequences of oscillation stored in memory as set values by using a microprocessor. The theremin is forming signals for driving a digital sound source by detecting the change in the frequencies of the oscillation circuits in accordance with the set values. As a result, the need for the frequency regulation of the oscillation circuits can be eliminated. The regulation operation after the startup is performed by giving rise to a drastic change in the periods by contact with the one antenna and by the updating the other set value by such detection.

It is also known from the international patent application number

WO20009127462 the gesture-controlled MIDI instrument with a movement controller and an integrated microcontroller and appropriate assemblies for generating note values and for controlling further sounds parameters. In this solution the human movements are captured through the use of a plurality of sensors. The interpretation of the gestures is forwarded by means of MIDI protocol to connected follow-on devices which then generate the sound. Positioned in or on the MIDI instrument are the requisite assemblies, which are the microcontroller, sensors, the MIDI interface and the rechargeable battery.

The main disadvantage of the electronic musical instruments, which are fitted with controllers or sensors for creating music using the gestures, is the need to hold these devices in hands and that they usually require a connection through a complex system of cables. Although there are electronic musical instruments fitted with optical sensors allowing "to release" hands, their precision and sensitiveness are too small. The possibilities of known electronic musical instruments fitted with one theremin are largely limited by the little space of reaction for a movement.

The advantage of the electronic musical instrument according to the invention is to use two theremins as movement sensors. Theremins are sensitive, precise and they respond to the movement of the entire body of the musician and also to the every gesture around the antenna, what allows to get natural effects. Theremins are also readily available on the market. By adding second theremin it is possible to extend the capabilities of the instrument significantly. It results in a significant increase in surface area around the device.

The technical problem to be solved is to work out a new electronic musical instrument fitted with two theremins and to modify the frequency of their internal oscillators so as to limit their mutual interference and enhance the robustness of the system since two theremins placed next to each other show interference and result with a very instable signal.

The musical instrument according to the invention is characterized by having two theremins of different frequency of oscillators whose central antennas are preferably no further than 10 cm from each other, preferably 1 cm from each other. The instrument is fitted with an analog-to-digital converter, a microprocessor, an user interface, preferably all as elements of a laptop, an amplifier, and/or a mixer. A computers sound card serves as an analog-to- digital converter. The instrument is fitted with additional controls preferably in form of steering pedals. The microprocessor is fitted with a normalizing module which transforms the digital signal into values in the range between 0 and 1, so as the value "1" corresponds to the closest position of the hand relative to the external antenna and the value "0" corresponds to the remotest position of the hand relative to the external antenna. The steering pedals serve to adjust the closest and the remotest position of the hand relative to each antenna. The normalizing module compensates differences between the both theremins and makes it possible to change the reaction of theremins against nearing the hands to each antenna. For each antenna several signals are generated: a basic signal corresponding to the input signal, a speed signal corresponding to the actual speed of the hand movement, a signal of the distance A corresponding to the basic signal, from which changes of values resulted from the trembling of musician's hands are deleted, a signal of the distance B corresponding to the basic signal with additional inertia, a speed signal A corresponding to the speed from the distance signal A, a speed signal B corresponding to the speed from the distance signal B and a control signal "Trigger" generated when the speed signal A changes its direction. The instrument might be additionally fitted with a hub, which receives those signals and redirects them to modules generating or processing the sound. The hub 85 is controlled by the module which keeps user instruction set divided into scenes: each of them is a complete set of instructions determining reaction of the instrument to the motion between antennas. The user interface allows to control parameters of the instrument. It is fitted with a display showing the current values of the distance and the speed of the motion around antennas. The control 90 pedals are placed between theremins and connected to the microprocessor.

They allow to control the functions of the instrument. Control pedals are used to turn on and/or turn off the instrument and to change the playback rate of drum loops. The control signal "Trigger" might be shifted in time. The instrument is preferably fitted with the sampler. The instrument 95 is preferably fitted with the granular synthesis module and the filter module, which parameters are preferably modified by gestures.

The musical instrument according to the invention allows to limit the mutual interferences of theremins and to strengthen the system stability by modules which are reducing the interferences and compensating its various

100 characteristics. Furthermore, by very particular character of those interferences, it is possible to - by summing the amplitude values of both theremins - reduce them further. Removal of the interferences from the theremins signals, as well as its detailed calibration, depending on the user preferences, gives the user precision and convenience.

105 The solution according to the invention allows to direct the audio signal from theremins right to a linear computer input, for instance a laptop. Other sensors requires usually an additional interface and a larger number of cables. Theremins are available on the market and - in case of failure - they might be easily replaced by new ones, what distinguish them from instruments fitted with

110 more specialized sensors, which replacement might be expensive and long- lasting. The instrument according to the invention is easy to assemble and to transport. A computer (especially a laptop), pedals and two theremins after the assembling are packed into a compact case. The solution according to the invention is presented on the drawing,

115 where fig. 1 presents the instrument according to the invention, and fig. 2 the scheme of instrument construction in block layout.

The musical instrument is fitted with the movement sensors as two theremins 3, 4 of the different frequency of oscillators connected to the computer 5, which on their basis generates the multi-track electronic music.

120 Central antennas 11, 12 of the theremins 3, 4 are placed no further than 10 cm from each other, preferably 1 cm from each other. Theremins 3, 4 placed close to each other cannot work properly, because they interfere with each other, hence it is necessary to modify them by principal change of the frequency of oscillators so that they do not overlap. After such tuning, theremins 3, 4

125 placed next to each other give a stable signal. After this modification it is not possible to use theremins 3, 4 in traditional way, because after the distance between them is increased, the signal fades out. The instrument according to the invention is fitted with the analog-to-digital converter, the microprocessor, the user interface, preferably all as elements of the laptop 5, the speakers 7, 8

130 and the amplifier 9, and/or the mixer 10. The computer sound card serves as the analog-to-digital converter. This converter converts the analog sound of theremins 3, 4 to the digital sound. The instrument may be fitted with the additional controls preferably the steering pedals 6. The microprocessor is used for electronic processing of the digital signal. The sound from the theremins 3, 4

135 is analyzed and transformed into four independent values: the frequency of the left theremin 3, the amplitude of the left theremin 3, the frequency of the right theremin 4, the amplitude of the right theremin 4. Even after appropriate modifying both theremins 3, 4 they may still exhibit the tendency to the mutual interfere of their amplitudes, but those interferences (or vibrations) complement

140 each other, hence after their summing one receives more stable signal.

The disadvantage of this solution is the loss of one value (two amplitudes are replaced by one summed), but instead the received signal is more stable. The digital signal derived from the analog-to-digital converter of two frequency values and one amplitude is analyzed and transformed preferably by the normalizing module with which the microprocessor is fitted. The normalizing module which transforms the digital signal into values in the range between 0 and 1, so as the value "1" corresponds to the closest position of the hand relative to the external antenna 1, 2 and the value "0" corresponds to the remotest position of the hand relative to the external antenna 1, 2. The musician has a possibility to set the maximum and minimum value by using the pedals 6, preferably by setting hand in a position which is in the remotest position from external right antenna 1 and by pressing pedal 6, so as microprocessor can save the value. The normalizing module compensates differences between the both theremins 3, 4 due to the asymmetry in the way of reaction left 1 and right 2 external antenna caused by modification of theremin's oscillators 3, 4. In addition the normalizing module allows to change the reaction of theremins 3, 4 against nearing the hands to the antennas 1, 2, 11 or 12 preferably in order to adapt the instrument to the musician's preferences. For instance the way of reaction of theremins 3, 4 can be set so as nearing the hand to the external antenna 1 or 2 has much larger effect than setting hand in a position which is in the remotest position from external antennas 1 or 2. As a result both theremins 3, 4 serve as three very precise proximity sensors and they control the three zones before the musician - the left zone around the external left antenna 1, the central zone around the central antennas 11, 12 and the right zone around the external right antenna 2. Electronic musical instrument according to the invention generates for each antenna 1, 2, 11, 12 following signals: the basic signal, the speed signal, the signal of the distance A, the signal of the distance B, the speed signal A, the speed signal B and the control signal "Trigger". A musician can change the settings of all these signals to tune the instrument to his needs. The speed signal corresponds to the actual speed of hand's movement. The distance signal A corresponds to the value of the basic signal, where changes of values resulting from interference or trembling of user's hands are deleted. This signal is more stable than the basic signal, therefore it is then used by most modules. The distance signal B relates to the basic signal with additional inertia,

175 what makes the changes much slower even if the hand movement is quicker.

This signal is used to control the filters - this makes the changes of the music much more smooth. The speed signal A corresponds to the speed from the distance A, and the speed signal B corresponds to the speed from the distance B. Whereas the control signal "Trigger" is generated when the speed

180 signal A changes its direction, i.e. when the user after he gradually approached the hand to each antenna 1, 2, 11 or 12 starts to move the hand away. Due to this signal it is possible to execute movements which resemble hitting invisible objects in the air. With this signal the value of the distance A is returned while the direction of the movement is changed, as well as the maximum speed while

185 the movement is executed, which allows assigning various percussion sounds to several subzones in the space. For instance "hitting" a point in the space nearer to the external antenna 1 or 2 triggers one sound and "hitting" a point which is more distant from the antenna 1 or 2 triggers another sound. The maximal speed can influence such parameters as the loudness of the

190 percussion sound as well as the low-pass filter. This enables several "invisible" percussion instruments "positioned" between external antennas 1 and 2 to react against "hits" similar to real percussion instruments. Adjusting the parameters of this signal the user can also determine the lower threshold of the reaction against a certain movement, thus slight and accidental movements can

195 be filtered out and ignored.

The electronic instrument according to the invention is fitted with the hub which receives control signals and distributes them and turns into control signals for the modules responsible of generating and processing the sound. The algorithm determining may be changed during the performance.

200 The hub is controlled by the module storing a set of instructions divided into scenes of which each is a complete set of instructions describing the way in which the instrument reacts against the movement between antennas 1, 2, 11, 12. For instance the first scene can describe that the hits in the vicinity of the external antenna 1 generate the sound of hi-hat, the hits in the centre generate

205 the sounds of a drum kick, and the hits on the right - sounds of a snare drum, whereas the second scene can describe that the hits in the vicinity of the left external antenna initiate looping fragments of an audio recording, whereas the movements in the vicinity of central antennas 11, 12 and right external antenna 2 change the parameters of the filters operating on this recording.

210 The user interface allows control of the parameters of the behavior of the instrument; it can also be fitted with a display showing actual values of the distance and the speed of the movement around the antennas 1, 2, 11, 12. The steering pedals 6 are placed between theremins 3, 4, in order to be accessible for the user and are connected to the microprocessor. They allow

215 control of the operation of the instrument, change of the scene index, indicate the points in the space for calibration as well as switch on and switch off the instrument or temporarily stop it especially in order it does not react against passing-by persons. Using pedals it is possible to change the tempo of playing the percussion loops. The control signal "Trigger" can be shifted in time. It may

220 be advantageous especially when it is used for initiating the percussion loops, which should be synchronized with each other. During the performance even small mistakes (even of few milliseconds) can cause unintentional effects, thus the signal can be shifted in time so as it coincides with other music events (in most of musical programs it is called "quantization"). The electronic

225 instrument can be fitted with a sampler responsible for playing back samples of audio or percussion loops. The sampler receives control signals from the hub and initiates sounds which are based on these appropriate signals. It may be either isolated samples of percussion sounds or looped fragments of recordings. The sampler allows for creating with gestures a multilayer, complete 230 composition, for example one gesture initiates a percussion loop, a next adds a loop of a guitar other add single sounds of a piano (e.g. the nearer to the antenna the sound of the piano is higher). The microprocessor can be fitted with a module of granular synthesis which generates the sound. Depending on what instructions are in the code the sound is generated upon a different audio

235 file. The right hand moved in vicinity of the right external antenna 2 determines the pitch of the sound and the left determines the position in the audio file, from which the granules for the synthesis are taken. This enables especially to "sing" a particular fragment of an audio recording, where the right hand determines he pitch and the left hand determines which syllable is sung. Furthermore

240 the microprocessor is fitted with the filtering module, whose parameters are favorably modified by gestures. This module receives the digital audio sound and adds effects such as an echo or filters. Furthermore the solution according to the invention is favorably fitted with the analog-to-digital converter, especially in the form of audio output from the sound card of the laptop 5.

245 The stable signal from the theremins can serve as the control signal for any kind of devices, especially electronic musical instruments. The solution according to the invention is the complete system serving for the analysis of the movements of the hands and the conversion to a multi-track electronic composition, allows for performing a complete electronic composition with

250 the use of sampling, loops, granular synthesis and other programs or electronic devices contrary to other solutions which contain sensors or controllers, which usually enable only very simplified conversion of hand movement into the sound. The instrument according to the invention due to the internal script which is divided into scenes allows for performing much more complex music.

Claims

1. The electronic musical instrument fitted with the movement sensors connected to the computer, characterized it that, it comprises two theremins (3, 4) of different frequency of oscillators.

2. The electronic musical instrument according to claim 1, characterized in that, the central antennas (1, 2) of theremins (3, 4) are placed no further than 10 cm from each other, preferably 1 cm from each other.

3. The electronic musical instrument according to claim 1, characterized in that, it is fitted with the analog-to-digital converter, the microprocessor, the user interface, preferably all as elements of the laptop (5), the speakers (7, 8), the amplifier (9), and/or the mixer (10).

4. The electronic musical instrument according to claim 3, characterized in that, the analog-to-digital converter is the computer's sound card.

5. The electronic musical instrument according to claim 1, characterized in that, it is fitted with the additional controllers.

6. The electronic musical instrument according to claim 5, characterized in that, the additional controllers are steering pedals (6).

7. The electronic musical instrument according to claim 4 or 5 or 6, characterized in that, the microprocessor is fitted with the normalizing module.

8. The electronic musical instrument according to claim 7, characterized in that, the normalizing module transforms the digital signal into values in the range between 0 and 1, so as the value "1" corresponds to the closest position of the hand relative to the external antenna (1 or 2) and the value "0" corresponds to the remotest position of the hand relative to the external antenna (1 or 2).

9. The electronic musical instrument according to claim 8, characterized in that, the steering pedals (6) serve to adjust the closest position of the hand relative to the external antenna (1, 2, 11 or 12) and to adjust the remotest position of the hand relative to the external antenna (1, 2, 11 or 12).

10. The electronic musical instrument according to claim 7, characterized in that, The normalizing module compensates differences between the both theremins (3, 4).

11. The electronic musical instrument according to claim 7, characterized in that, the normalizing module makes it possible to change the reaction of theremins (3, 4) against nearing the hands to each antenna (1, 2, 11 or 12).

12. The electronic musical instrument according to claim 4 or 5, characterized in that, for each antenna (1, 2, 11, 12) is generated the basic signal corresponding to the input signal, the speed signal corresponding to the actual speed of the hand movement, the signal of the distance A corresponding to the value of the basic signal, from which changes of values resulted from the interferences or the trembling of musician's hands are deleted, the signal of the distance B corresponding to the basic signal with additional inertion, the speed signal A corresponding to the speed from the distance A and a control signal, the speed signal B corresponding to the speed from the distance B and the control signal "Trigger" generated when the speed signal A changes its direction.

13. The electronic musical instrument according to claim 12, characterized in that, it is fitted with the hub, which receives control signals and separates them or processes them into the control signals for the modules responsible for generating or processing the sound.

14. The electronic musical instrument according to claim 13, characterized in that, the hub is controlled by the module which keeps user instruction set divided into scenes: each of them is a complete set of instructions showing reaction of the instrument to the motion between antennas (1, 2, 11, 12).

15. The electronic musical instrument according to claim 3, characterized in that, the user interface allows to control parameters of the instrument.

16. The electronic musical instrument according to claim 3, characterized in that, the user interface is fitted with a display showing the current values of the distance and the speed of the motion around antennas (1, 2, 11, 12).

17. The electronic musical instrument according to claim 5, characterized in that, the steering pedals (6) are placed between theremins (3, 4) and connected to the microprocessor.

18. The electronic musical instrument according to claim 5, characterized in that, the steering pedals (6) allows to control the functions of the instrument.

19. The electronic musical instrument according to claim 5, characterized in that, the steering pedals (6) are used to turn on and/or turn off the instrument.

20. The electronic musical instrument according to claim 5, characterized in that, the steering pedals (6) are used to change the tempo of drum loops.

21. The electronic musical instrument according to claim 12, characterized in that, the control signal "Trigger" might be shifted in time.

22. The electronic musical instrument according to claim 7, characterized in that, the instrument is fitted with the sampler.

23. The electronic musical instrument according to claim 7, characterized in that, the microprocessor is fitted with the granular synthesis module.

24. The electronic musical instrument according to claim 7, characterized in that, the microprocessor is fitted with the filter module, which parameters are preferably modified by gestures.