Bimorph Diaphragm Formed by Two PZT Sheets on Micromachined Silicon for Sound Generation

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001887-001905
Author(s):  
Youngki Choe ◽  
Shih-Jui Chen ◽  
Eun Sok Kim
Keyword(s):  
Sound Pressure ◽  
Pressure Level ◽  
Laser Vibrometer ◽  
Acoustic Intensity ◽  
Electrical Fields ◽  
Low Viscosity ◽  
Sinusoidal Input ◽  
Floating Electrode ◽  
Driving Signal ◽  
Measurement Area

This paper describes a microspeaker (composed of a mechanically-polished PZT bimorph diaphragm and bulk-micromachined silicon top cover) that shows flat diaphragm displacement from DC to 16kHz. A bimorph diaphragm is formed by gluing two 127μm thick PZT sheets and attaching them to a micromachined silicon substrate. The front-side pre-deposited nickel electrode was patterned to maximize the stress distribution over a diaphragm with its four edges clamped, when it goes through bending displacement. With un-patterned floating electrode on one side of the diaphragm, the PZT bimorph can generate stresses with opposite signs along the thickness direction without the need of fine alignment among the electrode patterns. It is important to reduce the thickness of the glue layer between the two PZT sheets, in order to maximize the electrical fields inside the PZT sheets, since the glue layer takes some of the applied voltage away. With mechanical polishing and spin-coating of low viscosity resin epoxy, we have been able to reduce the glue layer thickness to about 1 μm with variation less than 0.5 μm from a typical 25μm thickness. The microspeaker with an encapsulating cylindrical package of about 0.5 cc inside volume produces sound pressure level (SPL) of 103.6 ~ 110 dB between 1.3 and 12 kHz when measured 5 mm away from the diaphragm with 190Vpeak-to-peak driving signal. The measured SPL drops as the frequency is reduced below 1 kHz, due to increasing wavelength and thus reduced total acoustic intensity over the measurement area. The diaphragm was measured (with a laser vibrometer) to produce uniform displacement from DC to 16kHz. With 190Vpeak-to-peak sinusoidal input, the displacement at the center of the diaphragm was measured to have 1.86μm displacement at the fundamental resonant frequency of 16.2 kHz.

Continuous subjective loudness responses to reversals and inversions of a sound recording of an orchestral excerpt

2011 ◽  
Vol 15 (3) ◽  
pp. 387-401 ◽  
Author(s):  
Sam Ferguson ◽  
Emery Schubert ◽  
Roger T. Dean
Keyword(s):  
Sound Pressure ◽  
Pressure Level ◽  
Sound Recording ◽  
Acoustic Intensity ◽  
Bottom Up ◽  
Processing Style ◽  
Subjective Loudness ◽  
Two Factors ◽  
Musical Context ◽  
Auditory Looming

Twenty-four respondents continuously rated the loudness of the first 65 seconds of a Dvořák Slavonic Dance, which was known to vary considerably in loudness. They also rated the same excerpt when the sound file was digitally treated so that (1) the sound pressure level (SPL) was inverted or (2) it was temporally reversed or (3) both 1 and 2. Specifically we wanted to see if acoustic intensity was processed into the percept of loudness primarily using a bottom-up (indifferent to timbral environment and thematic cues) or top-down style (where musical context, such as instrument identity and musical expectation affects the loudness rating). Comparing the different versions (conditions) allowed us to ascertain which style they were likely to be using. A single, six-second region was located as being differentiated across two conditions, where loudness seemed to be increased due to expectation of the instrument and orchestral texture, despite the lower SPL. We named this effect an auditory loudness stroop. A second region was differentiated between the two conditions, but its explanation appears to involve two factors, auditory looming perception and the reversal of stimulus note ramps. The overall conclusion was that the predominant processing style for loudness rating was bottom-up. Implications for further research and application to models of loudness are discussed.

Contributions of Voice and Nonverbal Communication to Perceived Masculinity–Femininity for Cisgender and Transgender Communicators

2020 ◽  
Vol 63 (4) ◽  
pp. 931-947
Author(s):  
Teresa L. D. Hardy ◽  
Carol A. Boliek ◽  
Daniel Aalto ◽  
Justin Lewicke ◽  
Kristopher Wells ◽  
...  
Keyword(s):  
Fundamental Frequency ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Vocal Tract ◽  
Presentation Mode ◽  
Pressure Level ◽  
Presentation Modes ◽  
Audiovisual Stimuli ◽  
Vocal Tract Resonance ◽  
Point Light

Purpose The purpose of this study was twofold: (a) to identify a set of communication-based predictors (including both acoustic and gestural variables) of masculinity–femininity ratings and (b) to explore differences in ratings between audio and audiovisual presentation modes for transgender and cisgender communicators. Method The voices and gestures of a group of cisgender men and women ( n = 10 of each) and transgender women ( n = 20) communicators were recorded while they recounted the story of a cartoon using acoustic and motion capture recording systems. A total of 17 acoustic and gestural variables were measured from these recordings. A group of observers ( n = 20) rated each communicator's masculinity–femininity based on 30- to 45-s samples of the cartoon description presented in three modes: audio, visual, and audio visual. Visual and audiovisual stimuli contained point light displays standardized for size. Ratings were made using a direct magnitude estimation scale without modulus. Communication-based predictors of masculinity–femininity ratings were identified using multiple regression, and analysis of variance was used to determine the effect of presentation mode on perceptual ratings. Results Fundamental frequency, average vowel formant, and sound pressure level were identified as significant predictors of masculinity–femininity ratings for these communicators. Communicators were rated significantly more feminine in the audio than the audiovisual mode and unreliably in the visual-only mode. Conclusions Both study purposes were met. Results support continued emphasis on fundamental frequency and vocal tract resonance in voice and communication modification training with transgender individuals and provide evidence for the potential benefit of modifying sound pressure level, especially when a masculine presentation is desired.

Influence of the Acoustic Reflex on Vowel Recognition

1986 ◽  
Vol 29 (3) ◽  
pp. 420-424 ◽  
Author(s):  
Michael Dorman ◽  
Ingrid Cedar ◽  
Maureen Hannley ◽  
Marjorie Leek ◽  
Julie Mapes Lindholm
Keyword(s):  
Auditory System ◽  
Sound Pressure ◽  
Dynamic Range ◽  
Recognition Accuracy ◽  
Pressure Level ◽  
Acoustic Reflex ◽  
The Poor ◽  
Stapedial Reflex ◽  
Vowel Recognition ◽  
High Sound

Computer synthesized vowels of 50- and 300-ms duration were presented to normal-hearing listeners at a moderate and high sound pressure level (SPL). Presentation at the high SPL resulted in poor recognition accuracy for vowels of a duration (50 ms) shorter than the latency of the acoustic stapedial reflex. Presentation level had no effect on recognition accuracy for vowels of sufficient duration (300 ms) to elicit the reflex. The poor recognition accuracy for the brief, high intensity vowels was significantly improved when the reflex was preactivated. These results demonstrate the importance of the acoustic reflex in extending the dynamic range of the auditory system for speech recognition.

Case study: Theoretical calculation model and variable condition analysis research on the water-splashing noise for natural draft wet cooling towers

2020 ◽  
Vol 68 (2) ◽  
pp. 137-145
Author(s):  
Yang Zhouo ◽  
Ming Gao ◽  
Suoying He ◽  
Yuetao Shi ◽  
Fengzhong Sun
Keyword(s):  
Theoretical Model ◽  
Sound Pressure Level ◽  
Water Droplet ◽  
Water Distribution ◽  
Sound Pressure ◽  
Cooling Tower ◽  
Distribution Patterns ◽  
Calculation Model ◽  
Pressure Level ◽  
Cooling Towers

Based on the basic theory of water droplets impact noise, the generation mechanism and calculation model of the water-splashing noise for natural draft wet cooling towers were established in this study, and then by means of the custom software, the water-splashing noise was studied under different water droplet diameters and water-spraying densities as well as partition water distribution patterns conditions. Comparedwith the water-splashing noise of the field test, the average difference of the theoretical and the measured value is 0.82 dB, which validates the accuracy of the established theoretical model. The results based on theoretical model showed that, when the water droplet diameters are smaller in cooling tower, the attenuation of total sound pressure level of the water-splashing noise is greater. From 0 m to 8 m away from the cooling tower, the sound pressure level of the watersplashing noise of 3 mm and 6 mm water droplets decreases by 8.20 dB and 4.36 dB, respectively. Additionally, when the water-spraying density becomes twice of the designed value, the sound pressure level of water-splashing noise all increases by 3.01 dB for the cooling towers of 300 MW, 600 MW and 1000 MW units. Finally, under the partition water distribution patterns, the change of the sound pressure level is small. For the R s/2 and Rs/3 partition radius (Rs is the radius of water-spraying area), when the water-spraying density ratio between the outer and inner zone increases from 1 to 3, the sound pressure level of water-splashing noise increases by 0.7 dB and 0.3 dB, respectively.

Sign in / Sign up

Export Citation Format

Share Document