Manipulating the Hardness of HATS-Mounted Ear Pinna Simulators to Reproduce Cartilage Sound Conduction

Round 1

Reviewer 1 Report

Comments for Manuscript ID: applsci-2053646

Title: Manipulating the hardness of HATS-mounted ear pinna simulators to reproduce cartilage sound conduction

General comment:

This work discussed a fascinating and valuable study for hearing and hearing aid research applications. The study generated cartilage conduction sounds in five different ear simulators, each made of polyurethane resin, to mimic the elasticity of human skin with varying hardness levels. The aim was to establish the method to measure the output of cartilage-conduction-based devices via the standardized head and torso simulator (HATS). I have read the manuscript with interest, as the writing was clear and easy to follow.

However, I have a few minor comments that, hopefully, will help to clarify certain matters as follow:

 

Abstract

The material used to generate the cartilage conduction sounds in this experiment (i.e. the polyurethane resin) was not specified in the method section of the abstract. This is important as the base material was the main difference from a similar study design reported earlier by the same group published in the Audiology Research journal in 2021 (Ref no 18), which used a silicon rubber base.

 

Introduction

OK.

 

Method

·         How did you measure the output? Did you use the probe microphone as in the earlier study?

·         The cartilage conduction transducer was fixed at the entrance of the external auditory canal between the concha wall and tragus, as shown  in Figure 2b (lines 108-109) – How much force applied in this measurement of output?

·         Human ear data were established from three human participants. Can you describe these participants a little bit more? How were they selected to represent the human ear data as comparison to the simulator output?

 

Results

·         Figures should be self-explained. Please add the title and legends for each figure. I know it was written in the text what would be easier to read the legends and titles for each figure.

·         Figure 3(d) Original – refers to what? Original silicon rubber-based HATS pinna simulator?

·         How did you measure the averaged error between the CCS generated by the simulator and human cartilage data?

 

Discussion

·         For the A10-A20 hardness levels, were you able to measure the mass and elasticity properties of these simulators as the transmitting medium of the sound propagation?

·         The large gap in output between the simulators and human ear above 5kHz, irrespective of the hardness levels – what would that suggest in terms of application of the new CCS HATS?

 

Conclusion

OK.

 

Overall recommendation

Accepted for publication with minor revisions as suggested above.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer

I thank you for giving your precious time and energy on reviewing our paper. My responses were written in the attached Word file. Please read it.

Best regards,

Ryota Shimokura

Author Response File: Author Response.docx

Reviewer 2 Report

Comments for author File: Comments.pdf

Author Response

Dear Reviewer

I thank you for giving your precious time and energy on reviewing our paper. My responses were written in the attached Word file. Please read it.

Best regards,

Ryota Shimokura

Author Response File: Author Response.docx