Electronic Drum Sound Source Phase Interference Control
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Solution Overview
Problem
Conventional electronic percussion instruments face issues with phase interference during sound synthesis, leading to 'sound thinning, and sudden changes in tone color when switching between waveform data based on beating velocity.
Innovation Solution
A sound source system for electronic percussion instruments that includes a struck surface, a struck sensor, and a sound generation control mechanism, which stores and processes waveform data with pitch and amplitude envelope data for sine wave components and residual components, allowing for seamless synthesis and smooth tone color changes based on detected hits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two pieces of waveform data are synthesized in a cross-fade section, then smooth volume change is achieved, but phase interference occurs causing sound thinning
Solution Approach 1:
The waveform data is segmented into multiple pieces corresponding to different beating velocities. Instead of cross-fading between pieces, the system selects and switches between pre-segmented waveform pieces, each optimized for specific velocity ranges, thereby avoiding phase interference while maintaining smooth transitions through proper sequencing.
Solution Approach 2:
The system changes the parameter of waveform selection based on beating velocity detection. By mapping velocity ranges to specific waveform pieces and using cross-fading on amplitude envelopes rather than entire waveforms, the system achieves smooth volume changes without the phase cancellation problems that occur when cross-fading complete waveform data.
2Speed
If waveform data is switched based on beating velocity, then dynamic response is improved, but tone color changes suddenly at switching points
Solution Approach 1:
The system performs preliminary organization of waveform data into multiple pieces, each pre-configured for specific velocity ranges. Transition regions are pre-defined where adjacent waveform pieces overlap in their applicable velocity ranges, allowing smooth cross-fading transitions that maintain tone color consistency while responding dynamically to velocity changes.
Solution Approach 2:
Cross-fading acts as an intermediary mechanism between discrete waveform pieces. By applying cross-fading to the amplitude envelopes of adjacent waveform pieces in transition regions, the system creates smooth transitions that bridge the gap between different velocity-based waveform selections, preventing sudden tone color changes while maintaining fast dynamic response.
3Measurement precision
If addition synthesis of sine waves is used for every harmonic overtone, then tone control precision is improved, but it is insufficient for percussion instruments with large temporal frequency changes
Solution Approach 1:
The system uses multiple waveform pieces that are dynamically selected and cross-faded based on detected beating velocity. Each waveform piece captures the temporal frequency characteristics appropriate for its velocity range, and the dynamic switching between pieces allows the system to adapt to large temporal frequency changes in percussion instruments while maintaining precise tone control through the cross-fading mechanism.
Data Source
AI summary
A sound source for an electronic percussion instrument and sound production control method thereof are provided. An electronic drum sound source device performs a weighting operation on four pieces of waveform information (pitch envelope, amplitude envelope, start phase) stored in a waveform table according to the beating conditions (hitting point position, velocity) based on the output from a struck sensor of an electronic drum pad. The electronic drum sound source device creates a sine wave on the basis of the waveform information whereon the weighting operation was performed, and generates musical sounds (sounds of percussion instrument) by synthesizing the sine wave with the waveforms of residual waveform data whereon the weighting operation was performed. The sine wave is not synthesized with waveform data other than the residual waveform data, and thus consistent musical sounds with no phase interference can be reproduced.