Textile Membranes Reused as a Tool for Noise Control
Round 1
Reviewer 1 Report
The paper deals with the optimization of the curvature of the sheets for a suitable sound absorption.
The technique in use is ray-tracing erroneously called sound beams.
The algorithms used in the simulation should be clarified.
To explain the values of the absorption coefficients of the sheets, the authors report Ref. 5.
But for a scientific paper the authors would have had to make their own acoustic measurements.
The sheets absorb by dissipation and work if they are placed at a distance from the wall, if left free they are acoustically transparent: the authors should clarify this behavior.
Rigid materials reflect sound waves, sheets depend on thickness and density, this assessment should be performed.
Regarding the application on the building, the authors carry out a theoretical study.
For closed acoustic environments, reference is made to the ISO 3382 standard which I do not see reported.
The authors should have carried out acoustic measurements in an empty room, and then carried out the calibration operation (see Rindel, Farina, Vorlander) and then proceeded to the simulation.
Author Response
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Author Response.docx
Reviewer 2 Report
Dear authors, I point out some general observations about the manuscript:
Line 107: repeated sentence.
Line 157: FEM or BEM methodologies are not explained.
Figures 5, 6 and 8 are not didactic enough to support the understanding of the study, as well as Figures 7a and 7b. It is probably a limitation of mine, but, in my understanding, it lacks clarity. Figure 8 is not referred to in the text.
Lines 297 and 386: the text refers to chapters, but aren't they topics?
Lines 648 and 491: sound level values in dB. Shouldn't they be in dB(A)?
Figures 23, 24, 26, 28, 30 and 31: It is interesting to insert titles for the graph axes.
Author Response
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Reviewer 3 Report
I have attached the file to this email.
Comments for author File: 
Comments.pdf
Author Response
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Round 2
Reviewer 1 Report
row 16 : error - Finite (no Final)
The problem is that to evaluate whether your theory works you have to compare it with experiments performed in pratice.
This has not been done.
So if your idea works conceptually, this should be verified with experiments: this has not been done.
Author Response
- "row 16 : error - Finite (no Final)" - Thank you for the indicated correction, it has been corrected
-
"The problem is that to evaluate whether your theory works you have to compare it with experiments performed in pratice.
This has not been done.
So if your idea works conceptually, this should be verified with experiments: this has not been done."
Thank you also for this observation. We fully understand, but these issues are particularly complex to verify in practice, especially if you do not have sufficient material or real space in which to place the analyses, since all the research was carried out ante operam. In general, theoretically, if the membrane is light, thin and not very stretched, the sound tends to pass through it partially, while if it is denser, thicker and more stretched, the sound will tend to be reflected from it. Starting from this summary sentence (also contained in the text of the article) an analysis was carried out which obviously presupposes a sound behavior favorable to analysis. It all depends on the type of material used. As implemented for the latest revision, the intent of the research would be precisely to develop such theoretical premises to substantiate the design process. Note, however, that this design process can still be used for other types of materials as well. What is important is the design and engineering process, which can be implemented with many other materials and in infinite locations and buildings, simply by considering different values ​​with regards to the creation and validation of the simulation model. Membranes are actually the material of choice as they are extremely important and promising in the acoustic field as well. Even if the theory favors their use (if they are considered membranes with favorable characteristics), we understand that a complete analysis requires the implementation to demonstrate in favor of the premises. Unfortunately we do not have the practical means to achieve them, but the intention is to start a collaboration with a lab of the Italian Research Center as soon as the building will be ready to develop the next step of the research.
We hope that you could understand our positive intentions and our path to next verifications.
Kind regards
Reviewer 2 Report
It was possible to verify that the suggested recommendations were fully accepted by the authors, offering greater clarity to the article.
Author Response
Thank you for your positive review.
Kind regards
Round 3
Reviewer 1 Report
I note that the paper has not been integrated with my observations.
I suggest you increase the references
I would like to point out that in the field of applied acoustics Sabine's formula is used only for rough estimates and provides for environments in which sound is diffused.
The graphs need to be improved, avoid putting numbers in the graphs, but you need to increase the quality of the graph images.
Author Response
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