title: Evaluation of combined dynamic compression and single channel noise reduction for hearing aid applications.
abstract: Single-channel noise reduction (SCNR) and dynamic range compression (DRC) are important elements in hearing aids. Only relatively few studies have addressed interaction effects and typically used real hearing aids with limited knowledge about the integrated algorithms. Here the potential benefit of different combinations and integration of SCNR and DRC was systematically assessed.
  
  
  
  Ten different systems combining SCNR and DRC were implemented, including five serial arrangements, a parallel and two multiplicative approaches. In an instrumental evaluation, signal-to-noise ratio (SNR) improvement and spectral contrast enhancement (SCE) were assessed. Quality ratings at 0 and +6 dB SNR, and speech reception thresholds (SRTs) in noise were measured using stationary and babble noise.
  
  
  
  Thirteen young normal-hearing (NH) listeners and 12 hearing-impaired (HI) listeners participated.
  
  
  
  In line with an increased segmental SNR and spectral contrast compared to a serial concatenation, the parallel approach significantly reduced the perceived noise annoyance for both subject groups. The proposed multiplicative approaches could partly counteract increased speech distortions introduced by DRC and achieved the best overall quality for the HI listeners.
  
  
  
  For high SNRs well above the individual SRT, the specific combination of SCNR and DRC is perceptually relevant and the integrative approaches were preferred.
authors.affiliation: a Medizinische Physik and Cluster of Excellence Hearing4all , Universität Oldenburg , Oldenburg , Germany and.
authors.forename: Steffen
authors.initials: S
authors.lastname: Kortlang
authors.affiliation: a Medizinische Physik and Cluster of Excellence Hearing4all , Universität Oldenburg , Oldenburg , Germany and.
authors.forename: Zhangli
authors.initials: Z
authors.lastname: Chen
authors.affiliation: b Speech Signal Processing and Cluster of Excellence Hearing4all , Universität Oldenburg , Oldenburg , Germany.
authors.forename: Timo
authors.initials: T
authors.lastname: Gerkmann
authors.affiliation: a Medizinische Physik and Cluster of Excellence Hearing4all , Universität Oldenburg , Oldenburg , Germany and.
authors.forename: Birger
authors.initials: B
authors.lastname: Kollmeier
authors.affiliation: a Medizinische Physik and Cluster of Excellence Hearing4all , Universität Oldenburg , Oldenburg , Germany and.
authors.forename: Volker
authors.initials: V
authors.lastname: Hohmann
authors.affiliation: a Medizinische Physik and Cluster of Excellence Hearing4all , Universität Oldenburg , Oldenburg , Germany and.
authors.forename: Stephan D
authors.initials: SD
authors.lastname: Ewert
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D012048:Correction of Hearing Impairment / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006309:Hearing; D006310:Hearing Aids; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009622:Noise / Q000009:adverse effects / Q000517:prevention & control*; D057240:Patient Preference; D010470:Perceptual Masking; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*; D011571:Psychoacoustics; D012815:Signal Processing, Computer-Assisted; D013065:Speech Intelligibility; D013067:Speech Perception; D013069:Speech Reception Threshold Test; D055815:Young Adult
keywords: Dynamic compression; hearing aids; hearing impairment; noise reduction; speech presence probability