Bone and tissue conducted speech has been used in noisy environments to provide a relatively high signal-to-noise ratio signal. However, the limited bandwidth of bone and tissue conducted speech degrades the quality of the speech signal. Moreover in very noisy conditions, bandwidth extension of the bone and tissue conducted speech becomes problematic. In this paper, speech generated from bone and tissue conduction captured using an in-ear microphone is enhanced using adaptive filtering and a non-linear bandwidth extension method. Objective and subjective tests are used to evaluate the performance of the proposed techniques. Both evaluations show a statistically significant quality enhancement of the noisy in-ear microphone speech with $\rho <0.0001$ after denoising and $\rho <0.01$ after bandwidth extension.

With the rise of hearables and the advantages of using in-ear microphones with intra-aural devices, accessibility to an in-ear speech database in adverse conditions is essential. Speech captured inside the occluded ear is limited in its frequency bandwidth and has an amplified low frequency content. In addition, occluding the ear canal affects speech production, especially in noisy environments. These changes to speech production have a detrimental effect on speech-based algorithms. Yet, to the authors' knowledge, there are no speech databases that account for these changes. This paper presents a speech-in-ear database, of speech captured inside an occluded ear in noise and in quiet. The database is bilingual (in French and in English) and is intended to aid researchers in developing algorithms for intra-aural devices utilizing in-ear microphones.

For underactuated mechanical systems the use of disturbance estimators has been limited. For fully actuated mechanical systems, disturbance cancellation techniques have been studied and used to reduce the effect of disturbances on system performance. Particularly, the extended high gain observer has shown promising results in performance recovery. However, using the extended high gain observer to estimate and cancel the disturbance in one link of an underactuated system results in adding that disturbance to other links. This paper explores the effects of applying the extended high gain observer to an underactuated mechanical system. We show that the extended high gain observer can be used to reduce the effect of disturbances in a rotary pendulum system.

Objective: Speech production in noise with varying talker-to-listener distance has been well studied for the open ear condition. However, occluding the ear canal can affect the auditory feedback and cause deviations from the models presented for the open-ear condition. Communication is a main concern for people wearing hearing protection devices (HPD). Although practical, radio communication is cumbersome, as it does not distinguish designated receivers. A smarter radio communication protocol must be developed to alleviate this problem. Thus, it is necessary to model speech production in noise while wearing HPDs. Such a model opens the door to radio communication systems that distinguish receivers and offer more efficient communication between persons wearing HPDs. Design: This paper presents the results of a pilot study aimed to investigate the effects of occluding the ear on changes in voice level and fundamental frequency in noise and with varying talker-to-listener distance. Study sample: Twelve participants with a mean age of 28 participated in this study. Results: Compared to existing data, results show a trend similar to the open ear condition with the exception of the occluded quiet condition. Conclusions: This implies that a model can be developed to better understand speech production for the occluded ear.

Using radio communication in noisy environments is a practical and affordable solution allowing communication between workers wearing Hearing Protection Devices (HPD). However, typical radio communication systems have two main limitations when used in noisy environments: first, the background noise is disturbing the voice signal picked-up and transmitted, and second, that voice signal goes to all listeners on the same radio channel regardless of their physical proximity. A new concept of a so-called " Radio Acoustical Virtual Environment" (RAVE) addressing these two issues is presented. Using an intra-aural instantly custom molded HPD equipped with both an in-ear microphone and miniature loudspeaker, undisturbed speech is captured from inside the ear canal and transmitted over the wireless radio to the remote listener. The transmitted signal will only be received by listeners within a given spatial range, such range depending on the user's vocal effort and background noise level. This paper demonstrates the technological challenges to overcome and the methodology involved in the implementation of RAVE.