Piezoelectric Transducer with Foam Intermediate Layer for Guitar Vibration Control
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Solution Overview
Problem
Conventional transducers for stringed musical instruments, such as acoustic guitars, face issues with sound quality and tone reproduction due to restricted vibration movement, inadequate vibration sensing, and insufficient attenuation of string vibrations, leading to impaired reproducibility and uneven frequency response.
Innovation Solution
A transducer system featuring a piezoelectric device with an adhesive layer and an intermediate layer made of a different material, such as wood, positioned on a reinforcing member under the bridge, allowing for improved vibration attenuation and reduced preload, enabling closer sound reproduction to the actual performance sound with adjustable tone settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a piezoelectric device is mounted under the saddle with strong compressive force from string tension, then the transducer is firmly fixed, but the transducer's free movement is obstructed and vibration transduction is impaired
Solution Approach 1:
A foam layer is introduced as an intermediary between the piezoelectric device and the bridge. This foam layer acts as a compliant mounting medium that transmits vibration effectively while allowing the piezoelectric device to maintain its piezoelectric characteristics, resolving the conflict between firm fixation and vibration transduction accuracy
Solution Approach 2:
The mounting structure uses a composite approach combining the rigid bridge, compliant foam material, and piezoelectric device. This composite mounting system allows each material to perform its optimal function: the bridge provides structural support, the foam provides compliant vibration transmission, and the piezoelectric device converts vibration to electrical signals
2Reliability
If the transducer is mounted on the body outer surface, then the vibration of the body can be sensed, but the sensed vibration greatly varies depending on mounting position requiring complex adjustment
Solution Approach 1:
The transducer system is segmented into multiple piezoelectric devices arranged in a specific pattern on the bridge. This segmentation allows each device to sense vibrations from different string groups, and through weighted summation, achieves position-independent vibration sensing without requiring complex mounting position adjustments
3Device complexity
If only an adhesive layer is used to mount the piezoelectric device, then the structure is simple, but the vibration attenuation is insufficient causing output level saturation
Solution Approach 1:
The mounting structure uses a composite of adhesive layer and foam layer. The adhesive provides simple bonding while the foam provides superior vibration attenuation through its cellular structure. This composite approach maintains structural simplicity while achieving the required vibration attenuation performance
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 transducer system enhances sound quality and reproducibility by effectively attenuating vibrations, stabilizing frequency response, and simplifying the adjustment process, while preventing acoustic feedback and maintaining consistent output levels across different plucking forces and frequency bands.
Implementation Method 1
a transducer 51 made of a piezoelectric device which is a long, narrow piece is disposed under a saddle 52
Implementation Method 2
a transducer includes a coil positioned inside a sound hole and is capable of transducing the vibration of strings into an electric signal by electromagnetic induction of the coil
Data Source
AI summary
A transducer includes a piezoelectric element attached to a stringed musical instrument with an adhesive layer, and at least one intermediate layer provided in a thickness-wise middle portion of the adhesive layer and made of a material different from a material of the adhesive layer. The transducer has a mounting surface attached to face a back surface of a top of a body of the stringed musical instrument, and the mounting surface is disposed in an area, in the top, including an area right under an installation area of a bridge which is provided on a front surface of the top and supports a saddle supporting one-end sides of strings.