Different Types Of Microphones Research Articles

Geographical variation in Isophya camptoxypha (Orthoptera, Tettigoniidae) male songs: Part 1—Solo performance across different microphones

Through the analysis of male-song characteristics in Isophya camptoxypha (Fieber), a Curve-tailed plump bush-cricket species prevalent in the highlands of the Alps and the Carpathians, this study establishes that acoustic signals not only serve for species identification among closely related counterparts but also contribute to biogeographical assumptions and constructions. The investigation delves into the formation of a relict locality on Stinka Mountain, situated at the junction of two Carpathian biogeographical regions. Additionally, the research explores the implications of using different types of microphones for bioacoustic measurements.

Do Different Types of Microphones Affect Listening Effort in Cochlear Implant Recipients? A Pupillometry Study.

It is known that subjects with a cochlear implant (CI) need to exert more listening effort to achieve adequate speech recognition compared to normal hearing subjects. One tool for assessing listening effort is pupillometry. The aim of this study is to evaluate the effectiveness of adaptive directional microphones in reducing listening effort for CI recipients. We evaluated listening in noise and listening effort degree (by pupillometry) in eight bimodal subjects with three types of CI microphones and in three sound configurations. We found a correlation only between sound configurations and listening in noise score (p-value 0.0095). The evaluation of the microphone types shows worse scores in listening in noise with Opti Omni (+3.15 dB SNR) microphone than with Split Dir (+1.89 dB SNR) and Speech Omni (+1.43 dB SNR). No correlation was found between microphones and sound configurations and within the pupillometric data. Different types of microphones have different effects on the listening of CI patients. The difference in the orientation of the sound source is a factor that has an impact on the listening effort results. However, the pupillometry measurements do not significantly correlate with the different microphone types.

Comparative Analysis of HRTFs Measurement Using In-Ear Microphones.

The head-related transfer functions (HRTFs) describe the acoustic path transfer functions between sound sources in the free-field and the listener's ear canal. They enable the evaluation of the sound perception of a human being and the creation of immersive virtual acoustic environments that can be reproduced over headphones or loudspeakers. HRTFs are strongly individual and they can be measured by in-ear microphones worn by real subjects. However, standardized HRTFs can also be measured using artificial head simulators which standardize the body dimensions. In this paper, a comparative analysis of HRTF measurement using in-ear microphones is presented. The results obtained with in-ear microphones are compared with the HRTFs measured with a standard head and torso simulator, investigating different positions of the microphones and of the sound source and employing two different types of microphones. Finally, the HRTFs of five real subjects are measured and compared with the ones measured by the microphones in the ear of a standard mannequin.

Subjective studies on floor impact sound using headphone

Due to the pandemic situation, it become complex to conduct subjective experiments in the anechoic chamber as a result of the lockdown. For this situation the procedure for the subjective experiments without accessing to the anechoic chamber needs to be considered for an alternative approach. The previous study has shown that there are good correlation between the laboratory and online listening test on impact sounds in residential buildings using ambisonic microphone recording with headphone. Hence, further subjective experiments were carried out with monaural and binaural microphone recordings in an experimental buildings in Japan. The subjective experiment using a headphone in anechoic chamber was held in AIST, Japan. The 3 different floor types, 2 different types of microphones (mono and binaural), at 12 different combinations of impact sources, excitation positions and microphone positions were tested. This study also provided some evidence, and suggested there are potential of the online/remote subjective experiment using headphone.

Сучасні системи сценічного звукового забезпечення

The purpose of the article is to review, systematize and analyze the functional characteristics of the sound supply means of stage productions. The research methodology consists of the following approaches: system-historical (to study the problem), art history (to clarify the role of the sound system in modern stage practice), structural-analytical (for the functional classification of the components of the stage sound system). Scientific novelty. In the offered research the modern sound maintenance system of theatrical and entertaining productions is considered, its basic constituent elements have been systematized and analyzed; the role of technical means in work of the sound director on sound imagery creation of production has been comprehended. Conclusions. The study found that the profession of theater sound director and entertainment productions involves, in addition to sound recording skills, selection, editing and musical montage, noise, voice and other types of sound effects in accordance with the director’s design, and the ability to work with analog and digital sound equipment. It has been established that the main elements of the stage sound equipment system include microphones, monitors, amplifiers, speakers and mixing consoles. For example, during a rock concert on stage, musicians and vocalists use different types of microphones, place combo amplifiers of their electric instruments next to musicians; monitors on the floor in front of them invisible audiences shoot from the side of the stage or hang over the portal arch mirror the stage and directed towards the listeners are portals. In the center of the auditorium is a sound engineer’s console. It has been proved that an important component of the system of quality sound design is the room’s acoustic characteristics, which must be taken into account and improved during the events organization. It has been found that with the help of modern wireless sound systems it is possible to create conditions for theatrical and entertainment events without restrictions on their acoustic characteristics.

Detecting Parkinson’s disease with sustained phonation and speech signals using machine learning techniques

This study investigates the processing of voice signals for detecting Parkinson’s disease. This disease is one of the neurological disorders that affect people in the world most. The approach evaluates the use of eighteen feature extraction techniques and four machine learning methods to classify data obtained from sustained phonation and speech tasks. Phonation relates to the vowel /a/ voicing task and speech to the pronunciation of a short sentence in Lithuanian language. The audio tasks were recorded using two microphone channels from acoustic cardioid (AC) and a smartphone (SP), thus allowing to evaluate the performance for different types of microphones. Five metrics were employed to analyze the classification performance: Equal Error Rate (EER) and Area Under Curve (AUC) measures from Detection Error Tradeoff (DET) and Receiver Operating Characteristic curves, Accuracy, Specificity, and Sensitivity. We compare this approach with other approaches that use the same data set. We show that the task of phonation was more efficient than speech tasks in the detection of disease. The best performance for the AC channel achieved an accuracy of 94.55%, AUC 0.87, and EER 19.01%. When using the SP channel, we have achieved an accuracy of 92.94%, AUC 0.92, and EER 14.15%.

Improving the accuracy of smart devices to measure noise exposure

ABSTRACTOccupational noise exposure is one of the most frequent hazards present in the workplace; up to 22 million workers have potentially hazardous noise exposures in the U.S. As a result, noise-induced hearing loss is one of the most common occupational injuries in the U.S. Workers in manufacturing, construction, and the military are at the highest risk for hearing loss. Despite the large number of people exposed to high levels of noise at work, many occupations have not been adequately evaluated for noise exposure. The objective of this experiment was to investigate whether or not iOS smartphones and other smart devices (Apple iPhones and iPods) could be used as reliable instruments to measure noise exposures. For this experiment three different types of microphones were tested with a single model of iPod and three generations of iPhones: the internal microphones on the device, a low-end lapel microphone, and a high-end lapel microphone marketed as being compliant with the International Electrotechnical Commission's (IEC) standard for a Class 2-microphone. All possible combinations of microphones and noise measurement applications were tested in a controlled environment using several different levels of pink noise ranging from 60–100 dBA. Results were compared to simultaneous measurements made using a Type 1 sound level measurement system. Analysis of variance and Tukey's honest significant difference (HSD) test were used to determine if the results differed by microphone or noise measurement application. Levels measured with external microphones combined with certain noise measurement applications did not differ significantly from levels measured with the Type 1 sound measurement system. Results showed that it may be possible to use iOS smartphones and smart devices, with specific combinations of measurement applications and calibrated external microphones, to collect reliable, occupational noise exposure data under certain conditions and within the limitations of the device. Further research is needed to determine how these devices compare to traditional noise dosimeter under real-world conditions.

Speaker recognition regardless of context and language on a fixed set of competitors

The problem of speaker recognition from a given set of speakers for any language and any context is considered. A database of Russian numerals that contains speech segments from 216 men and 177 women, each of whom spoke from 400 to 800 words, is used for recognition. Speech has been recorded on different types of microphones in different rooms at the natural noise level. Recognition is based on solutions of the inverse problem of finding the voice excitation pulse shape for each pitch period by the known speech segment. The pulse shape is defined as the inverse Fourier transform of the regularized ratio of speech signal spectra at the intervals of the open and closed glottis. Recognition is carried out by ten parameters: the pitch period, the open glottis interval duration, times when the source amplitude is maximum, minimum, or zero, the amplitude ratio for the minimum and maximum source pulses, three decomposition ratios of the source function by the principal component method, and the vowel duration. In such a recognition procedure, in the case of the utterance of a word that contains one vowel, the false reject rate (FRR) for men is 1.7---5.4%, and the false acceptance rate (FAR) is 5.4---7.1%. For women FRR = 2---5.2% and FAR = 5.2---6.3%. The recognition error decreases with an increasing number of vowels in the speech signal. At 10 vowels, for men FRR = 0.05---0.2% and FAR = 0.07---0.8%, and for women FRR = 0.09---0.2% and FAR = 0.17---2.1%.

Wireless communication systems for masks or helmets

Various types of wireless communication systems for masks or helmets can be mounted externally or internally on a mask. Different types of microphones can be employed, for example, a bone-conducting microphone or a directional microphone. Ear speakers mounted at various locations on the mask or helmet can be employed. Wireless communication is with a transceiver mounted in or on a lapel unit, a walkie-talkie, or at a remote location.

Optical measuring and calibration techniques for microphones

Microphone measurement techniques are normally based on acoustical excitation and electrical derivation of either the voltage or the current output of the transducer. With condenser microphones, electrical excitation can be used as well. Calibration of microphones based on acoustical excitation therefore is quite time consuming, and sensitive for several errors originating in inaccurate sound-field properties and environment conditions. Measurements of the microphone membrane velocity with optical means like the laser Doppler vibrometer technique offer an accurate, touchless method to derive the local movement at almost each point of the membrane. Excitation of the membrane can be accomplished by direct feeding of the transducer (due to its reversible construction), which provides highest accuracy for the derivation of either current or voltage at the terminals of the transducer. From the knowledge of the vibration characteristics and the excitation properties, the ‘‘differential transducer sensitivity’’ defined at each surface point can be derived. With numerical methods, like the discrete solution of the Helmholtz equation or BEM, the radiated sound can be calculated, and finally the overall microphone radiation pattern and sensitivity can be calculated. The described techniques were applied to different types of microphones. The measurement and calculation results will be shown.

Method of accommodating for carbon/electret telephone set variability in automatic speaker verification

In a speaker verification system, a method of compensating for differences in speech samples obtained during registration and those obtained during verification due to the use of different types of microphones is provided by filtering at least one of the samples such that the similarities of the two samples are increased. The filtered sample is used within the speaker verification matching process. A two-way comparison is disclosed in which both a verification speech sample and a reference sample are filtered with nonlinear microphone characteristics such as carbon microphone characteristics. A four-way comparison is also disclosed in which patterns produced from unfiltered verification and reference samples and patterns produced from the filtered verification and reference samples are compared to identify a match. A score is determined for each comparison. The comparison having the best score is used to determine if a match has occurred.

Comments on ’’Environmental effects on microphones of various constructions’’ [J. Acoust Soc. Am. 61, 206–210 (1977)

This paper purports to compare the effect of temperature and humidity on three different types of microphones; air-cpndenser, electret-condenser, on three different types of microphones; air-condenser, electret-condenser, and ceramic. One type, the air condenser, is ’’back vented through a d dehumidifier’’ and is thus not really exposed to humidity. It is not surprising to find that it is unaffected by humidity when protected in this way. Tables that are alleged to demonstrate long-term stability show changes in sensitivity that are probably due to residual moisture in the microphones.

Absolute Noise Level of Microphones—a Definition Proposed for Discussion

With high quality microphones, fluctuation noise becomes a problem. Analyzing the situation shows that the usual conception of the term “signal-to-noise-ratio” becomes ambiguous here; thus a gap appears, requiring the introduction of a definition. This should be based on the properties of the ear in order to characterize noise performance as perceived. A corresponding definition aiming at a nonambiguous noise rating is introduced, explained, and applied to different types of microphones—dynamic, condenser, and piezoelectric (sound cell type). Merits and weaknesses of the definition, and of possible modifications, and relations to a recently proposed definition of microphone efficiency are discussed. The new quantity termed “absolute noise level” or “absolute deafness” is defined as the loudness level of the noise heard at the acoustical end of an imaginary transmission system which, connected to the microphone terminals, would faithfully reproduce any sound signal present at the microphone, when the ambient sound fields at both microphone and listener locations are zero. This noise level represents the “hearing loss” introduced by listening via microphone-transmission-system instead of directly. The numerical value of absolute deafness (in Phon) is obtained from the microphone response and resistance curves, by a process based on Fletcher-Munson's work.

Interference Effects in Rooms*

A discussion of interference effects in rooms, and their influence upon syllable articulation and naturalness of reproduction. Results achieved with different types of microphones, placement of the microphone, and acoustic treatment of the room are discussed.