Sound Port Research Articles

Photoacoustic methane detection inside a MEMS microphone

An innovative laser based photoacoustic (PA) gas sensing concept with intrinsic miniaturization potential was developed and investigated for methane trace gas detection. An interband cascade laser (ICL) with an optical power of 8.5 mW targets a methane (CH4) absorption line feature around 3057.7 cm−1 (or 3270 nm). The ICL was focused into the sound port of a MEMS microphone, where the PA signal was generated and detected using a wavelength modulation concept (2f-WMS-PAS). The MEMS microphone was successfully implemented as an intrinsically miniaturized PA cell being gas sensing volume, acoustic resonator and sound transducer at once. Frequencies between 2 kHz and 100 kHz were investigated and used for methane detection. A sensitive and resonant methane detection at 41.8 kHz was investigated by concentration variations between 0 and 10 ppm CH4 in N2. A limit of detection (3σ-LOD) of 329 ppb was estimated. The long term stability of this sensor was investigated by the measurement of methane in ambient air. A noise equivalent concentration (NEC) of 14 ppb (parts per billion) at an average time of 10 s was estimated. This value corresponds to a normalized noise equivalent absorption (NNEA) of 2⋅10−8 W cm−1 Hz−1/2. Using the MEMS microphone directly as PA cell offers the possibility for an extremely miniaturized, highly sensitive and very cost-efficient photoacoustic trace gas sensor.

Analysis of total harmonic distortion of miniature loudspeakers used in mobile phones considering nonlinear acoustic damping.

Total harmonic distortion (THD) plays an important role in the performance of miniature loudspeakers used in mobile phones. Traditional nonlinear models fail to predict THD in the higher frequency domain. Significant discrepancies can be found between the prediction and measurement. In this study, an extended model considering nonlinear acoustic damping is proposed to address this issue. Flow separation occurring near the orifices of the sound port is of particular interest. Two velocity-dependent parameters were derived to model the nonlinear damping effect. Based on the extended model, the dynamics of miniature loudspeakers are described using the state-space method. Experiments and calculations confirm the validity of the extended model. The influence of nonlinear acoustic damping on THD is also discussed.

Immediate reconstruction of mandibular defect after treatment of medication-related osteonecrosis of the jaw (MRONJ) with rhBMP-2/ACS and miniplate: Review of 3 cases

IntroductionThe purpose of this study was to pursue, and to report the results of, mandibular reconstruction and rehabilitation of medication-related osteonecrosis of the jaw (MRONJ) patients having large critical-sized defects of the mandible using a combination of recombinant human bone morphogenetic protein-2 (rhBMP-2) and absorbable collagen sponge (ACS) with surgical miniplate without any grafting materials. Case presentationThree (3) patients aged 67 and 86 (2 patients) presented due to discomfort on the mandible. They all had a medical history of bisphosphonate and steroids treatment orally or intravenously, and all had been diagnosed as MRONJ stage 3. Sequestrectomy and saucerization were performed, and then a surgical miniplate (Hansolmedical, Korea) was adapted and fixed on the sound portion of the mandible. rhBMP-2 was loaded onto an ACS at a dose of 1.5 mg/cc. Several rhBMP-2 (Cowellmedi, Korea)/ACS (Ateloplug, TRMkorea, Korea) were placed into the bony defect with a surgical miniplate. All 3 patients recovered without complications. They all exhibited radiographic evidence of bone formation by 3 months postoperatively in every case. ConclusionsAll 3 patients were treated successfully with rhBMP-2/ACS and miniplate without any complications. This protocol reported herein represents a new approach to the surgical treatment of maxillofacial bone defects and deficiencies, especially in MRONJ patients.

Acoustic transmission line based modelling of microscaled channels and enclosures.

An analytical model is presented that describes the acoustical impedance of cylindrical tubes and concentrically connected systems of such tubes valid up to the ultrasonic application. This allows the evaluation of microsized geometries encountered in acoustical microdevices, such as housing enclosures and sound port Helmholtz resonators. Each tube is treated as an acoustic transmission line (TL). Connected tubes are described using a coupling impedance, which accounts for viscous and inertial effects due to duct size changes. The acoustic TL model is directly derived from Navier-Stokes and energy equation, including frequency dependent boundary layer effects of the viscous and thermal dissipation. The results for various evaluated enclosure and resonator geometries are in good agreement with finite element method (FEM) simulation in both audio and ultrasonic frequency range and are compared to dedicated lumped element models referenced in literature. The presented model provides benefits in three ways: it is faster than FEM simulation and allows an implementation into analytical models and circuit simulation tools. Finally, it allows geometries with characteristic dimensions close to and above the wavelength to be treated with high precision in contrast to lumped element models.

PHONETOVOX: A Novel Prototype Device for Alaryngeal Speech

Objective: To describe a prototype improvised hand held device for alaryngeal speech.
 Methods:
 Design: Instrument Innovation
 Setting: Tertiary Private Hospital
 Participants: Four listeners with normal hearing, were native Tagalog-speakers and had no previous experience with alaryngeal speech types participated in initial trials.
 
 Results: The prototype PHONETOVOX was fabricated using a soundproofed cellphone casing with an intra-oral sound port attachment and a cellphone was loaded with Pocket Talkbox v. 1.4.0 software. The device was tested for its ability to produce intelligible speech by using the cellphone as a substitute for the larynx using oral cavity resonators and articulators, producing a synthesized sound mimicking the human voice. The PHONETOVOX produced intelligible words. Initial testing using a C-V-C Tagalog Word List had 4 listeners identify 34, 35, 47, and 54 out of 93 words (37 to 58%), with an overall average intelligibility of 46%.
 
 Conclusion: Despite its restrictions in articulation and the wide range of results from the four listeners, our initial results may suggest the potential of PHONETOVOX as another modality for alaryngeal speech comparable to the 36 – 38 % intelligibility of commercially-available devices. Further trials with actual laryngectomees are needed to further establish intelligibility and acceptability.
 
 Keywords: Laryngectomy, Alaryngeal speech, Laryngeal Cancer

What's all that noise-Improving the hospital soundscape.

Hospital noise levels regularly exceed those recommended by the World Health Organization (WHO). It is uncertain whether high noise levels have adverse effects on patient health. High levels of noise increase patient sleep loss, anxiety levels, length of hospital stay, and morbidity rates. Staff conversation and auditory medical alarms are amongst the leading noise producing stimuli, with combinations of stimuli accounting for much of the high noise levels. The Hospital Consumer Assessment of Healthcare Providers and Systems survey shows a slight improvement in overall hospital noise levels in the United States, indicating a minor reduction in noise levels. Alarm ambiguity, alarm masking and inefficient alarm design contributes to a large portion of sounds that exceed the environmental noise level in the hospital. Improving the hospital soundscape can begin by training staff in noise reduction, enforcing noise reduction programs, reworking alarm design and encouraging research to evaluate the relative effects of noise producing stimuli on the hospital soundscape.

The similar rates of occurrence of consonants across the world's languages: A quantitative analysis of phonetically transcribed word lists

Via an analysis of nearly 7000 phonetically transcribed word lists representing every major linguistic family, this study examines the frequency with which languages use particular consonants. The results suggest that there is an underlying global similarity in the frequency of occurrence of these consonants. Some consonants are uncommon across the word lists, and do not occur frequently even in those languages in which they are used. In contrast, a few other consonants represent a large portion of sounds in the word lists, across regions and linguistic families. The analysis quantifies the pervasiveness of such sounds that are known to be, impressionistically, common in speech. A new method captures the overall similarity of consonants’ rates of occurrence across languages and families. This method offers one means of evaluating the extent to which individual languages or families deviate from, or adhere to, the typical patterns of consonant usage. It is suggested that the crosslinguistic similarity of consonant usage, in terms of rates of occurrence in word lists, likely owes itself to previously documented factors like the relative ease of articulation of some sounds. This new evidence suggests that the role of ease of articulation in shaping speech may be more influential than generally assumed, though other explanatory factors are also likely at work and these patterns require further exploration with more robust intralinguistic phonetic corpora.

Investigation on the Corrosion of Coated Steel Plates with Impact Defect using Divided Steel Plates

A method utilizing divided steel plates was used to investigate the corrosion of coated steel plates with impact defect while continuously submerged in 3% NaCl solution. The polarization behavior of circular divided steel plates was first compared to that of undivided ones. Half-cell potential and polarization resistance results show similar trend in divided and undivided form especially at the later stages of exposure. The method of using circular divided steel plates was then used to monitor the macrocell as well as microcell corrosion in coated steel plates induced with defect. The test results show that the defect causes macrocell corrosion to occur between the defect and sound portions. The impact defect also caused the reduction in the polarization resistance and consequently higher microcell corrosion at the neighbouring sound coated portions.

Seasonal Density Estimates of Tursiops truncatus (Bottlenose Dolphin) in the Mississippi Sound from 2011 to 2013

Abstract We conducted vessel-based line-transect sampling from December 2011 to November 2013 to quantify Tursiops truncatus (Bottlenose Dolphin) density over 8 consecutive seasons in the Mississippi Sound. Density estimates showed temporal variation ranging from 0.27 Dolphins/km2 (CV% = 31.3) in spring 2013 to 1.12 Dolphins/km2 (CV% = 21.6) in spring 2012. Density in winter and summer was stable compared to fall and spring, which fluctuated across years. We also noted spatial variation—density was commonly highest in the central and eastern portions of the Mississippi Sound. Spatial and temporal variation in temperature and salinity were potentially driving shifts in Bottlenose Dolphin density. Additional regularly collected density estimates using standardized protocols are needed in order to draw more definitive conclusions regarding the status and trend of this population.

Acoustical-Thermal Noise in a Capacitive MEMS Microphone

Since the size of silicon capacitive micro-electro-mechanical system (MEMS) microphones is getting smaller, the mechanical-thermal noise especially acoustical-thermal noise from the MEMS transducer becomes important taking a significant portion of the total noise. Acoustical-thermal noise caused by the flow resistance of microphone components, including the sound port on the package, perforation holes on the backplate, and the vent holes on the diaphragm, was investigated with lumped element models in this paper. The size of the ventilation holes on the backplate and the air-gap distance between the diaphragm and the backplate were designed to minimize the flow resistance. To estimate the acoustical-thermal noise sources, Johnson-Nyquist's relation was used for the flow resistance, and then the signal-to-noise ratio (SNR) was predicted only with acoustical-thermal noise. A capacitive MEMS microphone which has dual backplates to take advantage of the dual transductions has been compared with the single backplate microphone in terms of SNR. Although the advantage of dual transductions leads to SNR increases by $\sim 3$ dB, the prediction shows that the SNR of the double backplate microphones turns out to be merely 7% higher than the single backplate due to the viscous flow resistance and squeeze film damping caused by the additional backplate.

Circuit system analysis for real-time acquisition of bio-signals

Around the globe many deaths are being reported every year due to poor health monitoring system in rural areas and un-affordability by the people in the semi-rural areas. However, the evolution of bio-signal processing techniques which is a computer-based, compact, non-invasive and battery powered bio-signal monitoring solution can be reached to address this issue. An attempt has been made in this paper to analyse the developed real-time, low-cost acquisition and monitoring system in ORCAD 16.3 software. It introduces detailed analysis and explanation of the hardware circuit used to effectively acquire real-time noise-free ECG signals. Also it is adjunct to the doctors for the diagnosis purpose. The system includes instrumentation amplifier, DC restoration circuit, integrator, right leg driven amplifier and notch filter. Further it can be interfaced to a computer using sound port as a serial interface between circuit and PC for analysis in terms of features extraction. The developed circuit is compact and handy with low power consumption which realises low-cost and real-time processing.

CANAL HEARING DEVICE WITH DISPOSABLE BATTERY MODULE

A modular canal hearing aid assembly having a main module positioned in the ear canal and a disposable battery module laterally positioned in the ear canal. The main module incorporates the durable components of a hearing device including the receiver, microphone and electronics. The disposable battery module comprises consumable elements including battery and incoming sound port. The disposable battery module provides a unitary structure that is easier to handle, remove from the main module, and replace when any of the consumable elements is depleted or degraded. The canal hearing device assembly is generic in shape and provided with assorted seal tips for "instant fitting" without resorting to custom manufacturing.

LOW SOUND ATTENUATING HEARING PROTECTION DEVICE WITH FILTER ARRANGEMENT

A hearing protection device including a sound attenuating portion configured to be disposed within an ear canal of a user to obstruct a passage of sound, a channel formed through the sound attenuating portion configured to allow sound to pass through the sound attenuating portion when the portion is disposed within the ear canal, a tube disposed in the channel and configured to allow the sound in the channel to pass therethrough, and a filter disposed at one end of the tube and positioned at an interior of the sound attenuating portion, where the filter attenuates some of the sound passing through the tube.

HEARING INSTRUMENT WITH IMPROVED VENTING AND MINIATURE LOUDSPEAKER THEREFORE

The present invention relates to improvements in acoustical venting of hearing aid earmolds and to miniature loudspeakers with housing structures configured to support improved hearing aid venting. The miniature loudspeaker comprises a front chamber with first and second separate sound ports so as to allow the front chamber to form an integral part of the acoustical vent of the hearing aid earmold. Thus, while using the same opening in the hearing aid for both sound output and venting, sound from the outside of the hearing aid may be introduced into the users ear via the same opening.

EARPIECE DEVICE WITH MICROPHONE

An earpiece device includes a housing having a sound output portion, a speaker and a microphone. The speaker disposed in the housing includes a diaphragm and a sound transmitting hole. The diaphragm is located between the sound output portion and the sound transmitting hole. The microphone is disposed in the housing and covers the sound transmitting hole. A sound wave generated within an ear canal would be received by the speaker and delivered through the sound transmitting hole to the microphone for pickup.

MUSIC HEADPHONES FOR MANUAL CONTROL OF AMBIENT SOUND

A headphone and method for allowing manually controlled reception of ambient sound by a user. More particularly, the invention relates to a headphone for listening to an audio signal while allowing varying amounts of ambient sound to the user. In one aspect, the headphone comprises a manually-controllable physical characteristic that controls the amount of ambient sound accessible to the user. The physical characteristic can be sound ports that can be opened or closed. In another aspect, the headphone can comprise a microphone receptive of ambient sound, wherein the user can control the proportion of sound that comes from the ambient sound or the audio signal. The microphone can be part of a noise cancellation system.

CONFERENCE AUDIO SYSTEM

Even in a conference audio system having an automatic mute release device, it is possible to reduce a delay time from an utterance to output from a speaker. The system includes: an A/D converter (33) for converting an audio signal from a plurality of microphones into a digital signal; audio level detection means to detect whether the converted digital signal level indicates an utterance or no sound; audio data storage means (32) for temporarily storing the digital signal in which the audio level detection means has detected an utterance; control means (31) for controlling storage of the audio data into the audio data storage means (32) and read out of the audio data; and a D/A converter (34) for converting the read-out audio data into an analog audio signal. When the audio level detection means has detected no sound in the series of audio data, the control means (31) hastens the audio data read-out timing in correspondence to the time of the no sound portion.

Card-Type Sound Apparatus And Electronic Appliance Provided Therewith

A card-type sound apparatus has, on a card-shaped substrate, a combination of a sound signal input portion to which a sound signal is input from outside and a sound generation portion that generates sound according to the sound signal input to the sound signal input portion, or a combination of a sound collection portion that collects sound from outside and converts the sound into an electric signal and a sound signal output portion that outputs to outside the electric signal obtained from the sound collection portion, or both of these combinations. The sound generation portion generates sound by making the card-shaped substrate itself vibrate according to the sound signal input to the sound signal input portion. The sound collection portion collects sound by converting the vibration of the card-shaped substrate itself into an electric signal.

Low Sound Attenuating Hearing Protection Device

A hearing protection device and a method of manufacturing thereof is provided. The device includes a sound attenuating portion for being disposed within an ear canal of a user to obstruct the passage of sound and a channel formed through the sound attenuating portion for allowing sound to pass through the sound attenuating portion.

Keypad Assembly For A Mobile Terminal

A keypad assembly for a mobile terminal includes a shielding element to prevent sound leakage from or into a sound port that is used to guide sound to a terminal microphone. A mobile terminal may include a printed circuit board (PCB) coupled to a keypad assembly and mounted within a case or housing, wherein a microphone is integral with the PCB. The shielding element is located between the microphone and the terminal case to form part of the sound port, and may be integrated with the keypad assembly.