An open-source mobile device for outside-lab sound field research

Transcription

1 An open-source mobile device for outside-lab sound field research Institute of Hearing Technology and Audiology Jade University of Applied Sciences Inga Holube with contributions from Jörg Bitzer, Sven Franz, Holger Groenewold, Sven Kissner, Ulrik Kowalk, and Petra von Gablenz

2 Sound fields for research? Resound.ch Advancedbionics.com Medel.com 2

3 Individual everyday life? Experience in everyday life: individual, momentary, multi-dimensional Ecological Momentary Assessment (EMA) Description of situations with subjective and objective data using a mobile smartphone-based system Privacy aware no audio recordings Hearing aid dummys: audifon 3

4 Smartphone-based System Android, 2 omni-directional microphones, USB audio interface Full-day stereo recording of acoustic parameters Online calculation of: Power Spectral Densities Root Mean Square (RMS) Zero Crossing Rate Frame-based feature extraction Sampling rate: 16 khz Data per hour: 130 MB Dynamic range: db Battery life approx. 8 hours Bitzer et al. (2016) Privacy-aware acoustic assessments of everyday life. JAES 64(6),

5 Privacy aware Smoothing of power spectral density (time constant = 125 ms) is applied Young normal-hearing listeners with sentence test at comfortable level Bitzer et al. (2016) Privacy-aware acoustic assessments of everyday life. JAES 64(6),

6 Individual assessment Adaptive, single and multiple choices Locations and activities 7-point categorical scales to assess: Loudness Listening effort Pleasantness Importance Speech understanding Speech sources (presence, familiarity, number) Time delay of assessment Ø 1 min assessment duration (median) Mobeval: Phonak 6

7 Data collection 47 participants (19 males), age yrs (Ø 70 yrs) Age-typical, mild to moderate hearing loss, no hearing aids Sampled from volunteer database of Hörzentrum Oldenburg Approx. 6-8 hours per day for Ø 4 days, Ø 19 assessments per subject per day Combined event and time based sampling (reminder every 30 min) N = 2814 valid completed assessments n = 1682 cases with valid acoustical data 7

8 Offline analysis: Own voice Segments containing the subject s own voice excluded based on coherence 8

9 Subjective and objective data Fingerprint of objective and subjective data during individual days, e.g.: s m m too l m vs m m l l m m m m Acoustical data derived from time frames of past min before assessment Time shift of assessment considered 9

10 Locations and activities Reported locations and activities Overall, approx. 2/3 of the assessments refer to activities in the subject s private places Among the activities in public places, many assessments correspond to mobility situations 10

11 Level in octave bands Levels in octave bands. Median (dots), lower and upper quartile (bars). Data refer to highest level in either the right or left ear Highest levels particularly in the low frequencies below 1 khz relate to mobility situations Levels are lowest in private places n=1072 n=106 n=142 n=178 n=227 11

12 Shortcomings Not wearable by BTE users not applicable for hearing aid evaluation Usability and reliability: Two separate apps without interface Hardware configuration with multiple cable connections 12

13 New developments Individual Hearing Aid Benefit in Real Life (IHAB-RL) Funded by the research consortium of the hearing aid industry (IRC) Cooperation with Markus Meis at Hörzentrum Oldenburg Assessment tools for momentary hearing-related quality of life Improved Hardware Enhanced Software 13

14 Hardware concept Microphones attached to glasses (removable) Wireless connection Stereo Bluetooth A2DP Hardware monitoring Suitable for BTE hearing aid users 14

15 Software concept Single user interface Robust design Auto-start Notifications Process monitoring Flexible subjective assessment XML based configuration Flexible scheduling Additional analysis tools 15

16 Source: Wikimedia Commons Challenges Small and ultra-portable circuit for ADC and Bluetooth transmission Power supply for long-term measurements Flexible mounting of hardware without affecting existing hearing aids Android smartphone as stereo Bluetooth sink Custom ROM with features from Android Car Usage and interface tailored towards technically challenged users 16

17 Source: Wikimedia Commons Open source Open source licenses for software and hardware Free distribution (as in speech and in beer) of binaries and source code Enables collaboration Own modifications/enhancements possible Free schematics for custom-built components Remaining parts freely available 17

18 Discussion Ideas and wishes: Additional features Preferred ways of distribution Suggestions on handling 18

19 Thanks to Funded by the federal resources of Niedersächsisches Vorab by the Ministry of Science and Culture of Lower Saxony within the research focus Hearing in everyday life Data collection by Lena Haverkamp, Florian Schmitt, and Maximilian Hehl Technical support by Elmar Fichtl and Vincent Meyer (Sonova) and the company audifon and The Hearing Industry Research Consortium (IRC) 19