Electronic Piano Sound Generation Using Convolution and Impulse Response
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Solution Overview
Problem
Conventional electronic pianos struggle to accurately simulate the natural resonant tones of an acoustic piano using feedback filter signal processing techniques, resulting in unrealistic sound reproduction.
Innovation Solution
A musical note generation device that attenuates sound waveform data by reducing frequency component amplitudes of fundamental tones and harmonics, followed by a convolution operation with impulse response data to generate resonant tone waveform data, mimicking the damper pedal effect in acoustic pianos.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If feedback filter signal processing techniques are used to simulate resonant tones, then the device complexity is reduced, but the sound realism deteriorates
Solution Approach 1:
The patent records actual resonant tone waveforms from an acoustic piano and stores them as impulse response data. This copied real-world data is then used directly in convolution operations to generate realistic resonant tones, eliminating the need for complex feedback filter algorithms while maintaining high sound realism.
2Measurement precision
If convolution operation with impulse response data is performed, then the sound realism is improved, but the calculation amount increases
Solution Approach 1:
The patent pre-calculates and stores impulse response data for different pitch ranges (low, middle, high) before runtime. During actual operation, the system only needs to retrieve the appropriate pre-computed impulse response and perform a single convolution operation, rather than calculating resonance in real-time, thus maintaining high sound realism while reducing computational burden.
Solution Approach 2:
The patent divides the impulse response data into multiple sets corresponding to different pitch ranges (low sound range, middle sound range, high sound range). The system selectively applies only the relevant impulse response set based on the played note's pitch, avoiding unnecessary calculations and reducing overall computational load while maintaining accuracy.
3Measurement precision
If multiple impulse response data sets are used for different pitch ranges, then the sound accuracy is improved, but the memory requirements increase
Solution Approach 1:
The patent segments impulse response data into three distinct sets corresponding to low, middle, and high pitch ranges. This segmentation allows the system to store comprehensive acoustic characteristics across the entire piano range while using only one-third of the memory that would be required to store a single complete impulse response, as each set is used for specific pitch ranges only.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively produces natural resonant tones similar to those of an acoustic piano, enhancing the realism and authenticity of electronic piano sounds.
Implementation Method 1
a convolution operation process that convolves the attenuated sound waveform data generated by the attenuated sound waveform data generation process with at least one of a plurality of second sound waveform data sets respectively corresponding to a high sound range side impulse response and a low sound range side impulse response
Implementation Method 2
an attenuated sound waveform data generation process of generating attenuated sound waveform data by respectively reducing, among frequency components included in first sound waveform data corresponding to the pitch information associated with a specified key, amplitudes of respective frequency components of a fundamental tone and harmonics
Data Source
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AI summary
A musical note generation device includes at least one processor that performs a process of generating attenuated sound waveform data by respectively reducing, among frequency components included in first sound waveform data corresponding to pitch information associated with a specified key, amplitudes of respective frequency components of a fundamental tone and harmonics of the fundamental tone corresponding to a pitch indicated by the pitch information; a process that convolves the generated attenuated sound waveform data generated with at least one of a plurality of second sound waveform data sets respectively corresponding to a high sound range side impulse response and a low sound range side impulse response, so as to generate third sound waveform data; and a process of outputting piano sound waveform data generated on the basis of the third sound waveform data generated by the convolution process.