Effect of Diffusion Conditions on Absorption Performance of Materials Evaluated in Reverberation Chamber
Round 1
Reviewer 1 Report
The topic of the paper is of undoubted interest and very current, in fact an update work is in progress within ISO (ISO TC 43 SC2 WG35) of the standard 354. In particular, two ILTs on the subject are in progress as described in the following publications; take them in the consideration:
- Scrosati C et a. Design Principles of the Italian Round Robin Test on Reverberation Rooms, Proceedings of the 23rd International Congress on Acoustics (ICA 2019), Aachen,9-13 September 2019;
- Scrosati C, Scamoni F, Depalma M, Granzotto N. On the diffusion of the sound field in a reverberation room, Proceedings of the 26th international congress on sound and vibration (ICSV 2019), Montreal, 7–11 July 2019;
- Edoardo A. Piana, Nicolaas Bernardus Roozen, Chiara Scrosati The denorms round robin test: measurement procedure and post-processing of time data, Proceedings of the 26th international congress on sound and vibration (ICSV 2019), Montreal, 7–11 July 2019;
- Scrosati C., Roozen N.B., Piana E.A., principles at the basis of the denorms round robin test on the low frequency sound absorption measurements in reverberation rooms and impedance tube, Proceedings of the 26th international congress on sound and vibration (ICSV 2019), Montreal, 7–11 July 2019.
A large number of studies, have been pointing out the limited reproducibility of absorption coefficients measured in different laboratories and several explanations for such a large spread are possible: the difference among room volume and shape, the use of Sabine’s formula, edge effects, particularly for thick samples. The results obtained in the described experimentation can make a significant contribution to the improvement of the test procedures but shall be verified among many different laboratories and samples and shall be added to the other aspects described above.
The paper can be published but only after a revision: in particular it must be reorganized to expose the procedures applied in an orderly way and without repetitions and making explicit the meaning of quantities and equations even if described in articles in the references; the introduction of many different parameters in different points of the paper can create confusion.
See attached file for detailed remarks.
Comments for author File: 
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Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
very interesting and useful work. I have no further comments to make. for me it can be published
Author Response
Thank you very much for your approval of publishing this paper.
Reviewer 3 Report
Please add some information about Boards ( what material ? and source). Modify the tile specifying the type of material. it is too general. I suggest rethinking the title. Does it really reflect your narrative and data presented ?Author Response
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Author Response File: Author Response.docx
Reviewer 4 Report
This paper concerns measuring the sound absorption coefficients of building materials using a method which can take the differences of the reverberation chambers into account. I can suggest publication on the condition that authors appropriately address the following issues:
authors used the objective diffusion evaluation indicator to validate the proposed indicator. Advantages of the proposed indicator should be given here compared to the objective one. The method used for extrapolation should be briefly described in section 2.2.2. Marks should be added to the end of equations. Legends needed for figures 7 and 8. Size of the captions of figures should be consistent.Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
The authors have addressed the reviewer's concerns.
