Front Speaker Research Articles

Masked Speech Recognition as a Function of Masker Location for Cochlear Implant Users With Single-Sided Deafness.

Cochlear implant (CI) recipients with normal or near normal hearing (NH) in the contralateral ear, referred to as single-sided deafness (SSD), experience significantly better speech recognition in noise with their CI than without it, although reported outcomes vary. One possible explanation for differences in outcomes across studies could be differences in the spatial configurations used to assess performance. This study compared speech recognition for different spatial configurations of the target and masker, with test materials used clinically. Sixteen CI users with SSD completed tasks of masked speech recognition presented in five spatial configurations. The target speech was presented from the front speaker (0° azimuth). The masker was located either 90° or 45° toward the CI-ear or NH-ear or colocated with the target. Materials were the AzBio sentences in a 10-talker masker and the Bamford-Kowal-Bench Speech-in-Noise test (BKB-SIN; four-talker masker). Spatial release from masking (SRM) was computed as the benefit associated with spatial separation relative to the colocated condition. Performance was significantly better when the masker was separated toward the CI-ear as compared to colocated. No benefit was observed for spatial separations toward the NH-ear. The magnitude of SRM for spatial separations toward the CI-ear was similar for 45° and 90° when tested with the AzBio sentences, but a larger benefit was observed for 90° as compared to 45° for the BKB-SIN. Masked speech recognition in CI users with SSD varies as a function of the spatial configuration of the target and masker. Results supported an expansion of the clinical test battery at the study site to assess binaural hearing abilities for CI candidates and recipients with SSD. The revised test battery presents the target from the front speaker and the masker colocated with the target, 90° toward the CI-ear, or 90° toward the NH-ear.

Individual Differences Offer Insight Into Clinical Recommendations for Directional and Remote Microphone Technology Use in Children.

Purpose This study sought to evaluate the effects of common hearing aid microphone technologies on speech recognition and listening effort, and to evaluate potential predictive factors related to microphone benefits for school-age children with hearing loss in a realistic listening situation. Method Children (n = 17, ages 10-17 years) with bilateral, sensorineural hearing loss were fitted with hearing aids set to include three programs: omnidirectional, adaptive directional, and omnidirectional + remote microphone. Children completed a dual-task paradigm in a moderately reverberant room. The primary task included monosyllabic word recognition, with target speech presented at 60 dB A from 0° (front) or 180° (back) azimuth. The secondary task was a "go/no-go," visual shape-recognition task. Multitalker babble noise created a +5 dB SNR. Children were evaluated in two speaker conditions (front, back) using all three hearing aid programs. The remote microphone transmitter remained at the front speaker throughout testing. Speech recognition performance was calculated from the primary task while listening effort was measured as response time during the secondary task. Results Speech presented from the back significantly increased listening effort and caused a reduction in speech perception when directional and remote microphones were used. Considerable variability was found in pattern of benefit across microphones and source location. Clinical measures did not predict benefit patterns with directional or remote microphones; however, child age and performance with omnidirectional microphones did. Conclusions When compared to a traditional omnidirectional setting, the directional and remote microphone configurations evaluated in this study have the potential to provide benefit for some children and increase difficulty for others when used in dynamic environments. A child's performance with omnidirectional hearing aids could be used to better inform clinical recommendations for these technologies.

Sound intensity transfer path analysis and its application to analyze the acoustics in vehicle interior

A new technology based on conventional transfer path analysis (TPA) called sound intensity TPA (SITPA) is proposed and applied to analyze the acoustic field in a vehicle interior excited by a pair of front speakers. First, we introduce an analogy of a mass-spring-damper system for our intuitive understanding of sound intensity. On the basis of the analogy, we determined that the active and reactive components of sound intensity represent energy transmission and storage in the acoustic field, respectively. Next, formulation of SITPA, which extends the capability of conventional TPA, is introduced and demonstrates how SITPA expresses the sound intensity at the receiver by using the sum of partial sound intensities transferred from multiple sound sources. Application of SITPA shows that the active and reactive components of partial sound intensities generated by the interference of front-left and front-right speakers can be changed by modifying not only acoustic transfer characteristics of the vehicle interior but also phase-lag of input signals for speakers. The effect of modifying the phase-lag on the sound intensity is experimentally examined under the scheme for minimizing and maximizing reactive sound intensity.

P‐112: Sound Quality Improvement of a Flat‐Panel Display Front Speaker: Emotional and EEG Test of Exciter Speaker

Along with the development in OLED TV panel manufacturing technology, the thickness of the panel is thinned, and the durability is also improved. It is also possible to generate sound by directly driving the panel. In this study, we have analyzed the acoustic characteristics of a directly driving the OLED panel speakers, using electroencephalography(EEG), in addition study the advantages of direct driving sound. OLED TV with direct drive speakers has a basic effect of matching the positions of the screen and sound. This is because the direction of the sound and the direction of the screen coincide with the viewers of the TV, so that the stress is less and the viewing is comfortable compared to the conventional TV. The acoustic characteristics of proposed OLED speakers are high in resolution. And the sound quality is better than ordinary TVs, because of direct transferred sound instead of listening to reflections or differenced sound sources compared with.

SOUND SYSTEMS FOR MODEL RAILROAD LOCOMOTIVES

On-board model railroad speaker enclosure designs are presented that allow maximum sized speakers, improve impedance matching of sound to the outside of the locomotive, and isolate back and front speaker waves while maintaining the standard horizontal drive-train in model train locomotives.

Sensing Driver Phone Use with Acoustic Ranging through Car Speakers

This work addresses the fundamental problem of distinguishing between a driver and passenger using a mobile phone, which is the critical input to enable numerous safety and interface enhancements. Our detection system leverages the existing car stereo infrastructure, in particular, the speakers and Bluetooth network. Our acoustic approach has the phone send a series of customized high frequency beeps via the car stereo. The beeps are spaced in time across the left, right, and if available, front and rear speakers. After sampling the beeps, we use a sequential change-point detection scheme to time their arrival, and then use a differential approach to estimate the phone's distance from the car's center. From these differences a passenger or driver classification can be made. To validate our approach, we experimented with two kinds of phones and in two different cars. We found that our customized beeps were imperceptible to most users, yet still playable and recordable in both cars. Our customized beeps were also robust to background sounds such as music and wind, and we found the signal processing did not require excessive computational resources. In spite of the cars' heavy multipath environment, our approach had a classification accuracy of over 90 percent, and around 95 percent with some calibrations. We also found, we have a low false positive rate, on the order of a few percent.

Bilateral Cochlear Implantation for Children in Nagasaki, Japan

ObjectivesThe number of patients with bilateral cochlear implant (CI) has gradually increased as patients and/or parents recognize its effectiveness. The purpose of this report is to evaluate the efficacy of 29 bilateral CI out of 169 pediatric CI users, who received auditory-verbal/oral habilitation at our hearing center.MethodsWe evaluated the audiological abilities 29 Japanese children with bilateral CIs including wearing threshold, word recognition score, speech discrimination score at 1 m from front speaker (SP), 1 m from second CI side SP, speech discrimination score under the noise (S/N ratio=80 dB sound pressure level [SPL]/70 dB SPL, 10 dB) at 1 m from front SP, word recognition score under the noise (S/N ratio=80 dB SPL/70 dB SPL, 10 dB) at 1 m from front SP.ResultsBinaural hearing using bilateral CI is better than first CI in all speech understanding tests. Especially, there were significant differences between the results of first CI and bilateral CI on SDS at 70 dB SPL (P=0.02), SDS at 1 m from second CI side SP at 60 dB SPL (P=0.02), word recognition score (WRS) at 1 m from second CI side SP at 60 dB SPL (P=0.02), speech discrimination score (SDS) at 1 m from front SP under the noise (S/N=80/70; P=0.01) and WRS at 1 m from front SP under the noise (S/N=80/70; P=0.002). At every age, a second CI is very effective. However, the results of under 9 years old were better than of over 9 years old on the mean SDS under the noise (S/N=80/70) on second CI (P=0.04). About use of a hearing aid (HA) in their opposite side of first CI, on the WRS and SDS under the noise, there were significant differences between the group of over 3 years and the group of under 10 months of HA non user before second CI.ConclusionThese results may show important binaural effectiveness such as binaural summation and head shadow effect. Bilateral CI is very useful medical intervention for many children with severe-to-profound hearing loss in Japan as well as elsewhere.

Earphone Set With Detachable Speakers Or Subwoofers

An apparatus is provided including a first speaker which emits sound, a second speaker which emits sound, and a device which connects the first speaker and the second speaker. The device may connect the first speaker or front speaker, and the second speaker or rear speaker, so that the device can be attached to an ear of a person so that the first speaker lies near the middle of the ear while the second speaker lies at a location between an ear lobe of the ear and a mastoid of a skull of the person.

SOUND PROCESSING SYSTEM USING SPATIAL IMAGING TECHNIQUES

A sound processing system reduces the instances when only a center speaker is heard. The gain of a volume setting is adjusted for individual speakers in response to one or more input signals. The gain of the center speaker is attenuated in relation to the global volume setting. In addition or as an alternative, the gain of front and/or rear speakers is increased. A virtual center channel is generated for locations where the center speaker may not be heard.

MULTI-CHANNEL AUDIO ENHANCEMENT SYSTEM

A method for processing audio signals can include receiving left and right front audio signals and left and right rear audio signals, where the left and right rear audio signals. In addition, the method can include applying at least one front perspective filter to each of the left and right front audio signals to yield filtered left and right front output signals, where the left and right front output signals each drive a front speaker. Moreover, the method can include applying at least one rear perspective filter to each of the left and right rear audio signals to yield left and right rear output signals, where the left and right rear output signals each drive a rear speaker to simulate a rear surround sound effect when positioned in front of a listener.

Apparatus For Generating Surround Signal From Two-Channel Stereo Signal

To restrict a loss, or a variation in a loudness, of the sound of a rear speaker if the separation of a two-channel stereo signal degrades in a surround device which generates a four-channel surround signal based on a difference component of the two-channel stereo signal. In a surround device which generates the difference signal based on input left and right channel signal, and generates a driving signal of a front speaker arranged in front of the audience and a driving signal of a rear speaker arranged behind the audience based on the left and right input signals and the difference signal, a part of the driving signal of the front speaker or a part of the two-channel signal is mixed to the driving signal of the rear speaker, and therefore, the loss or the variation in the loudness of the sound of the rear speaker can be restricted even if the separation of the two-channel stereo signal degrades.

A binaural model to evaluate surround sound reproduction systems using head movements.

Recently, a binaural model was proposed, which utilized head movements to resolve front-back confusions [Braasch et al., J. Acoust. Soc. Am. 127, 1886]. Meanwhile, the binaural model has been extended to evaluate the benefit of surround loudspeakers for the reproduction of diffuse sound. For this purpose, two to four loudspeaker locations were simulated using head-related transfer functions (HRTFs). To simulate head movements, the HRTFs were adjusted in steps of 1 deg to maintain the loudspeaker positions in a room-related coordinate system. Uncorrelated white-noise bursts (1-s duration) were fed to each loudspeaker channel. The superposed spatialized signals were processed through a gammatone filter bank to measure coherence and interaural-level (ILDs) differences in individual frequency bands. Various loudspeaker configurations were tested. The study shows that coherence and ILDs for diffuse sound vary less with head movements if surround speakers (e.g., ±120 deg) are used in addition to a pair of front speakers (e.g., ±30 deg). For example, if the head is turned between ±40 deg, the maximum coherence drops from 0.58 to 0.39 if surround loudspeakers are added (600-Hz frequency band). At 5000 Hz, the maximum ILD magnitude is reduced from 10 to 4 dB with surround loudspeakers.

Speaker system having a front speaker integrated with a reflection-type surround speaker

A surround speaker system according to the present invention includes an integral speaker in which a surround speaker is integrally formed with a front speaker, a canceling device for canceling a directly propagating sound of the surround speaker, and a reflective device for reflecting the output sound of the surround speaker.

Surround sound speaker system

The present invention uses multivoice coil drivers in conjunction with the small satellite speakers of multichannel surround sound systems to achieve an overall linear response between 100 Hz to above 15 KHz. The multivoice coil drivers are designed to respond only to frequencies that fall between conventional upper base and lower midrange crossover frequencies which typically extend between 75 Hz and 225 Hz. The invention relies on the characteristics of human hearing which limits the listener's ability to localize the source of sound approximately to the wavelength of the sound being heard. The system may be incorporated in existing front and rear center speakers or separate enclosures to supplement the overall surround sound system.

A hybrid approach to rendering multichannel audio, using wave-field synthesis and stereophonic techniques, with virtual microphone control

In the evolution of multichannel audio presentation, a number of formats have emerged including 5.1 surround and wave-field synthesis (WFS). Due to the complexity and number of components required to realize an immersive WFS system, the use in a home theater environment is currently impractical. This study aims to investigate the perceptual advantages of integrating both systems into a hybrid array capable of providing immersive sound for a number of listeners, at a scale that is attainable for the consumer in terms of budget and complexity. In this approach the three front speakers (left, center, and right) are replaced with a linear line array allowing for a better lateral and depth imaging, while increasing the sweet spot. The rendering will be created using Virtual Microphone Control (ViMiC) for both WFS, simulating a line of omnidirectional microphones with ViMiC, and surround sound, which will allows dynamic source movement, speaker positioning, and scalability. The advantage of using this hybrid approach is the application of WFS to home theater systems without facing the complexity of a complete two-dimensional WFS array, while still allowing for an immersive sound presentation. A psychoacoustic evaluation will be presented, as well as measurements of the composed sound field.

System for transitioning from stereo to simulated surround sound

This invention provides a system capable of transitioning from surround sound effect to stereo sound effect, and then to a monophonic sound effect using front speakers. A user may control the amount of surround sound effect that is combined with stereo sound effect, and the amount of stereo sound effect that is combined with monophonic sound effect. The user may also control the system to hear pure surround sound effect, stereo sound effect, or monophonic sound effect. The system may allow a user to control the contribution of a particular sound effect by controlling the relative proportions of the filtered dipole signals and the attenuated unfiltered dipole signals. The signal processing may be also done through an analog device. The system may also process some audio channels in an inverted form and compensate for these inversions by reversing the polarity of that output to the speaker, as well as accept two-channel and four-channel audio inputs.

Surround signal processing apparatus and method

A surround signal processing apparatus and method can realize sound image localization and have reverberation effects. In the apparatus, left and right impulse measuring sections (302, 304) measure left and right impulses (hL, hR) of a head related transfer function (HRTF) for an input audio signal (Um) based on a number (h) of a plurality of lattices (404) defined in a three-dimensional space (402), horizontal and vertical angles defined by a center (c) of a dummy head (DH) and the plurality of lattices (404). Left and right convolution operators (306, 308) convolve left and right channel signals of input audio signal with left and right impulses of head related transfer function, respectively, in order to localize sound image for input audio signal at an objective localisation position. Left and right reverberators (310, 312) impart first and second reverberant sounds to left and right channel signals, respectively. According to the apparatus and method, it is possible to reproduce two pseudo surround signals from a pair of virtual rear speakers by use of a pair of actual front speakers; that is, to construct a 4-channel surround system by use of only two speakers. Further, they provide a listener with a feeling of presence as if he is listening to the music in a different sound field such as a spacious concert hall, church or stadium notwithstanding the fact that he is actually in an ordinary room, a listening room, or a vehicle.

5-2-5 matrix system

A matrix system encodes five discrete audio signals down to a two-channel stereo recording and decodes the recorded stereo signal into at least five stand alone, independent channels to allow placement of specific sounds at any one of 5 or more predetermined locations as individual, independent sound sources, thus producing a 5-2-5 matrix system. One embodiment of the system provides signals to left front, right front, center, left rear, and right rear speaker locations. The matrix system is compatible with all existing stereo materials and material encoded for use with other existing surround systems. Material specifically encoded for this system can be played back through any other existing decoding systems without producing undesirable results.

In-home theater surround sound speaker system

An apparatus (10) for realistically reproducing sound, particularly for sound based on a stereophonic signal having dialog and effects and associated with an accompanying video image. The apparatus includes a front speaker (20) located in proximity to the video image for providing acoustic output based upon a summation signal of the component left and right (L+R) channels of the audio signal. A rear speaker (26) located to the rear of the viewing area provides acoustic output based upon a difference signal, (L-R) or (R-L), between the left and right channels. Left and right speakers (22 and 24) are located to the respective left and right sides of the viewing area. The left and right channels speakers (22 and 24) reproduce in one embodiment the respective left and right channels of the audio signal and in a second embodiment reproduce a difference signal, (L-BR) or (R-BL), where B is a gain which may vary or may be a value fixed between zero and unity. Output to the left and right speakers (22 and 24) is band limited to substantially filter out frequency components below a predetermined threshold. A bass speaker (18) may also be provided to output the low frequency components of a (L+R) summation signal. The (L+R) summation signal input to the front speaker assists in localizing dialog to the video image. The (L-BR) or (R-BL) difference signal substantially removes dialog sound so that the side and rear speaker output primarily comprises sonic ambience and surround sound effects. Band limiting the left and right speakers further assists in localizing dialog to the video image. Alternatively, in yet another embodiment, a monophonic signal may be applied to at least one embodiment of the system to enable production of a spatially enhanced surround sound effect.

Sound reproducing apparatus

A unit for use in coupling a pair of loudspeakers to an amplifier having two channels comprises a transformer having a first winding and a second winding, one end of a first winding having a first connection device for connecting the first winding in series with one of the loudspeakers, one end of the second winding having a second connection device for connecting the second winding in series with the other of the loudspeakers, the windings being electrically connected asymmetrically, and the other ends of the first and second windings having means for connecting the other ends to the negative supply line of the amplifier. This unit can be used advantageously in connecting the front speaker pair of a "surround-sound" or four speaker sound reproduction system. The remaining speaker pair is then connected in a conventional Hafler arrangement.