Electro Acoustics

Objectives: The main objective of this study was to measure the vibrotactile thresholds on the mastoid process and forehead positions using patients with bilateral deafness and to compare the results from the two bone conduction vibrators Radioear B71 and B81. Design: There is a possibility that the vibrotactile sensation on the skin makes it difficult to discriminate between sound and vibration. The risk is highest for patients who have bone conduction hearing thresholds in proximity to or worse than their vibrotactile thresholds. All measurements were performed similar to regular bone conduction threshold testing using an audiometer-driven bone conduction vibrator and pulsed warble tones, but the patients were instructed to respond only when feeling vibrations of the bone conduction vibrator instead of when hearing sound. Both the posterior forehead position and the mastoid process position on the temporal bone were tested for comparative reasons. In total, 16 patients participate...

This study examined the association between acoustic and perceptual data related to vibrato in Western operatic singing using recordings of performances by internationally famous opera singers. Three related studies were conducted. Study 1 used commercial recordings of the same five singers and the same cadenza examined by Siegwart and Scherer 1 , measured vibrato rate and extent in each singer's performance of the cadenza and tested possible associations between these vibrato attributes and judges' preference for singers. Studies 2 and 3, using recordings of different internationally famous singers and a different cadenza, measured vibrato onset, rate, and extent in each singer's performance of the cadenza, required judges to rank the singers in order of personal preference, to identify the emotion expressed, and to assess the degree of success in communicating emotion achieved by the singer. The findings showed that the perception of the singers' vibrato did not always agree with acoustic measurements. However, a comparison of the acoustic measurements with the preference and emotion judgments suggest that some elements of vibrato may affect listeners' perception of the voice, their preference for a particular singer, and assist the communication of emotion between singer and audience.

Objectives: The objective of this study was to develop methods for evaluating the mechanical robustness and estimating the lifetime of the novel bone conduction implant (BCI) that is used in a clinical study. The methods are intended to be applicable to any similar device. Materials and methods: The robustness was evaluated using tests originally developed for cochlear implants comprising a random vibration test, a shock test, a pendulum test, and an impact test. Furthermore, magnetically induced torque and demagnetization during magnetic resonance imaging at 1.5 T were investigated using a dipole electromagnet. To estimate the lifetime of the implant, a long-term age-accelerated test was performed. Results: Out of all the tests, the pendulum and the impact tests had the largest effect on the electro-acoustic performance of the BCI implant, even if the change in performance was within acceptable limits (<20%). In comparison with baseline data, the lower and higher resonance peaks shifted down in frequency by 13% and 18%, respectively, and with a loss in magnitude of 1.1 and 2.0 dB, respectively, in these tests. Conclusion: A complete series of tests were developed, and the BCI passed all the tests; its lifetime was estimated to be at least 26 years for patients who are using the implant for 12 hours on a daily basis.