Musical Tone Signal Research Articles

Construction of Vocal Timbre Evaluation System Based on Classification Algorithm

With the continuous development of communication technology, computer technology, and network technology, a large amount of information such as images, videos, and audios has grown exponentially, and people have started to be exposed to massive multimedia contents, which can easily and quickly access the increasingly rich music resources, so new technologies are urgently needed for their effective management, and automatic classification of audio signals has become the focus of engineering and academic attention. Currently, music retrieval can be achieved by selecting song titles and singer names, but as people’s living standards continue to improve, the spiritual realm is also enriched. People want to be able to select music with different types of emotional expressions with their emotions. It mainly includes the basic principles of audio classification, the analysis and extraction of music emotion features, and the selection of the best classifier. Two classification algorithms, hybrid Gaussian model and AdaBoost, are used to classify music emotions, and the two classifiers are combined. In this paper, we propose the Discrete Harmonic Transform (DHT), a sparse transform based on harmonic frequencies. This paper derives and proves the formula of Discrete Harmonic Transform and further analyzes the harmonic structure of musical tone signal and the accuracy of harmonic structure. Since the timbre of musical instruments depends on the harmonic structure, and similar instruments have similar harmonic structures, the discrete harmonic transform coefficients can be defined as objective indicators corresponding to the timbre of musical instruments, and thus the concept of timbre expression spectrum is proposed, and a specific construction algorithm is given in this paper. In the application of musical instrument recognition, the 53-dimensional combined features of LPCC, MFCC, and timbre expression spectrum are selected, and a nonlinear support vector machine is used as the classifier. The classification recognition rate is improved by reducing the number of feature dimensions.

Vibration source driving device

A vibration source driving device that realizes various vibration functions on portable telephones. The vibration source driving device includes a sound source for generating musical tone signals in response to music data. A vibration source to generate vibration, a driver to drive the vibration and a control circuit are further included such that the vibration source may be driven in synchronization with the rhythm signal within the music data.

Time-axis compression/expansion method and apparatus for multichannel signals

A time-axis compression/expansion method and apparatus for multitrack signals is provided, which is capable of performing time-axis compression/expansion on a multitrack signal in such an appropriate manner as to prevent a degradation in the sound quality of a sound generated through a multichannel reproduction or a sound generated through reproduction of a musical tone signal obtained by mix-down. Positions of attacks of the rhythm track sound source signal of a plurality of track sound source signals are detected. Portions of the rhythm track sound source signal between the detected positions of attacks are subjected to a first time-axis compression/expansion process, and the other track sound source signals are subjected to a second time-axis compression/expansion process, based on the detected positions of attacks.

Sound effect generator and audio system

A sound field effect adding apparatus is provided to add such effects as reverberation to the musical tone signal of an electronic organ and the like, and to produce a sound field effect. It is possible to create a satisfactory reproduced sound field to which a sound field effect has been added by means of a low frequency component without having to provide a dedicated unit or dedicated speaker system that can reproduce low frequencies. The apparatus has an input terminal with which a musical tone that includes a low frequency is input, and a means in which a sound field added musical tone signal is generated that produces a sound field effect that is based on an input musical tone signal. The apparatus has a first output terminal with which this sound field added musical tone signal is output to a speaker system used for sound field reproduction, and a generation means in which a low frequency component of the sound field added musical tone signal that contributes to the production of the sound field effect that is related to the low frequency is generated, which is different from the sound field added musical tone signal that is output by the first output terminal. The apparatus also includes a second output terminal with which this low frequency component is output to an external device.

Electric musical instrument

An electric musical instrument is provided, which enables rich and diverse expressions to be achieved in musical performance. A driving member drives a tone generating source. A driving member-side signal generator obtains a signal from the driving member and outputs the obtained signal. A musical tone signal generator generates a musical tone signal using the signal output by the driving member-side signal generator and outputs the generated musical tone signal. In another aspect of the invention, a tone generating source-side signal generator obtains a tone generating source-side signal from the tone generating source and outputs the obtained signal, and a driving member-side signal generator obtains a driving member-side signal from the driving member and outputs the obtained signal. A modulation device frequency-modulates one of the tone generating source-side signal and the driving member side signal with the other signal. The modulated signal is output from the modulation device as a sound.

Acoustic signal producing apparatus

An acoustic signal producing apparatus wherein various musical effects are applied to a musical tone signal and an acoustic signal respectively produced at an internal tone generator and supplied from an external device such as a microphone, an electronic musical instrument or the like in such a manner that an applying state of the musical effects can be changed in accordance with various effect control parameters applied thereto.

Waveform processing apparatus and an electronic musical instrument using the output waveform thereof

In the waveform processing apparatus of the present invention, an original sound signal is divided into a plurality of bands, parameters such as amplitude and frequency are extracted for each band, and correction is made so that the amount of deviation of the parameters from the mean value thereof is gradually decreased to zero from a certain time to the time when the repetition period begins, whereby a musical tone signal is re-synthesized based on the corrected parameters. The electronic musical instrument which stores the waveforms processed by the apparatus of the present invention generates musical tones having more natural tone color change.

Electronic musical instrument for simulating wind instrument musical tones

An electronic musical instrument simulating a wind instrument is fundamentally configured by a loop circuit at least containing a linear portion and a non-linear portion. The linear portion simulates a pipe portion of the wind instrument, while the non-linear portion simulates a breath-blowing portion of the wind instrument so as to produce an excitation signal, which is supplied to the linear portion. By an interaction between the linear portion and the non-linear portion which is carried out while a signal circulates through the loop circuit, a sounding characteristic of the wind instrument is simulated. In order to accurately simulate a jet reed instrument (e.g., organ pipe), there are further provided a delay circuit and an edge tone generator. The delay circuit imparts a delay time to the output signal of the linear portion, and then, a delayed signal is supplied to the non-linear portion. The delay time corresponds to a time which is required when an air flow passing through a slit reaches an edge in the jet reed instrument. The edge tone generator generates a noise signal representing an edge tone (or an aeolian tone) which is unique to the jet reed instrument. The noise signal is mixed with the output signal of the non-linear portion, and then, a mixed signal is supplied to the linear portion. Thus, a sound of the jet reed instrument can be accurately simulated by a musical tone signal picked up from the loop circuit.

Musical tone signal forming apparatus for use in simulating a tone of string instrument

A musical tone signal forming apparatus includes a pickup which detects vibrations of a string of an electric guitar and produces a string vibration signal. The string vibration signal and the output of a first delay imparting a first delay time are combined in a first combiner. Second and third delays impart second and third delay times to the string vibration signal, respectively. Delayed signals from the second and third delays are combined in a second combiner. Outputs of the first and second combiners are combined in a third combiner. The first delay time is determined by the distance between a bridge and a first imaginary pickup supposed to detect vibrations of the string. The second delay time is determined by the distance between the first imaginary pickup and a second imaginary pickup supposed to be disposed nearer to the bridge. The third delay time is determined by the distance between the bridge and the mid-point of the first and second imaginary pickups.

Filtering apparatus for an electronic musical instrument

A filtering apparatus for an electronic musical instrument includes at least a digital filter. The digital filter has a frequency characteristic determined by a filtering parameter and performs a filtering operation on a musical tone signal inputted thereto. In addition, the filtering parameter is changed in accordance with a keycode signal representing a tone pitch of the musical tone signal. Thus, the frequency characteristic is varied in accordance with a keycode signal.

Musical tone signal synthesizer

A musical tone signal synthesizer wherein a first waveform signal of a frequency defined by first frequency information is produced as a modulation signal, a second waveform signal indicative of a windowing function is produced at a cycle defined by second frequency information and a third waveform signal starting from a predetermined phase at each cycle of the second waveform signal is repeatedly produced at a shorter cycle than that of the second waveform signal, and wherein the second and third waveform signals are modulated by the first waveform signal and multiplied to produce a fourth waveform signal as a musical tone signal having a fixed formant characteristic comprised of a plurality of formants.

Feed-back loop type musical tone synthesizing apparatus and method

In a loop circuit having a low-pass filter, a delay circuit, and an all-pass filter, a wave signal read from a wave memory is supplied as an excitation signal to the loop circuit and circulated therein to synthesize a musical tone signal. A musical tone signal to be synthesized and processed by a signal processing system having a characteristic inverse to the loop circuit is stored in the wave memory.

Electronic keyboard musical instrument capable of varying a musical tone signal according to the velocity of an operated key

An electronic musical instrument reads data of a musical tone from a waveform memory thereof according to pitch information input thereto, to form a tone signal containing a tone amplitude signal indicative of amplitude of the musical tone. The tone signal is passed into a plurality of signal paths to be formed into a plurality of analog tone signals. The plurality of signals paths each amplify the tone amplitude signal according to a note on/off velocity, and attenuate a plurality of modifications of the tone signal, depending on or not depending on the note on/off velocity and the pitch information on the musical tone, to generate a musical tone suitably reflecting the note on/off velocity and the pitch.

Musical tone synthesizing apparatus utilizing an all-pass filter having a variable fractional delay

The musical tone synthesizing apparatus is mainly configured by a closed loop which at least provides a delay circuit and an all-pass filter. The delay circuit delays an input signal (e.g., excitation wave signal) by a first delay time corresponding to a certain integral number of sampling periods. The all-pass filter functions to at least delay an output of the delay circuit by a second delay time corresponding to a decimal fraction of the sampling period, so that an output of the all-pass filter is fed back to the delay circuit. The whole delay time of the closed loop consists of the first and second delay times which can be respectively controlled. Thus, a musical tone signal representing a synthesized musical tone (e.g., an attenuating sound which is produced from an percussion instrument) is picked up from the closed loop. Incidentally, the whole configuration of the closed loop can be embodied by a digital signal processor (DSP).

Emphasize system for electronic musical instrument

An emphasize system for an electronic musical instrument including filter and control device. The filter extract and output predetermined frequency range component of an input musical tone signal. The control device control the level of an output from the filter at least on the basis of an output from an envelope generator which controls the level of the input musical tone signal, or on the basis of the level of another frequency range component of the input musical tone signal. At least the level controlled signal is outputted from the system.

Electronic musical instrument with portamento function

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Musical tone waveform signal forming apparatus with pitch and tone color modulation

A musical tone waveform signal forming apparatus having a modulation function comprises a delay loop system including a delay circuit and a filter, a excitation signal input section, a control member and a filter characteristic control circuit. The excitation signal input to the delay loop system circulate therein, so that a musical tone signal is formed. The control member instructs modulation of a musical tone signal. The filter characteristic control circuit changes with time the characteristics of the filter in accordance with an output from the control member. So that pitch modulation accompanied with tone color modulation is effected.

Musical tone synthesizing device

PURPOSE: To generate musical tones having high natural feel by taking out either of the output signals of an adding means which adds an external input signal and plural feedback signals and plural delaying means which delay the signals and feedback the signals to the adding means as musical tone signals. CONSTITUTION: This device has the adding means B123 which adds the external input signal and the plural feedback signals and the plural delay means SF 1 to SF 3 , SF 2 to SR 3 which respectively delay the output of the adding means B123 by the different delaying time and feed back the signals to the adding means B123. Either of the output signal of the adding mans B123 or the output signals of the plural delay means SF 1 to SF 3 , SF 2 to SR 3 are taken out as the musical tone signals. The respective pairs of the shift registers SF 1 and SR 1 and the shift registers SR 3 and SR 3 respectively constitute resonance circuits and the resonance phenomena of percussion instruments, such as cymbals and drums, are simulated by these resonance circuits. The attenuation of the tones in the percussion instruments is simulated in this way and the resulted percussion instrument tones are outputted from the adder A123. The percussion instrument tones having the high natural feel are thus generated. COPYRIGHT: (C)1990,JPO&Japio

Breath controller for musical instruments

A breath controller for musical instruments includes a mouth piece for blowing the air into an air chamber. Blowing the air makes an air pressure increase in the air chamber, thus an elastic member is displaced corresponding to the air pressure. At the same time, the displacement of a reflection surface changes an amount of light to reflect an emitted light from a light-emitting element to a light-receiving element. The light-receiving element then controls a signal corresponding to the amount of light, thus making the signal change to a musical tone signal.

Motion-controlled musical tone control apparatus

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