A Sound Source Localization Method Based on Frequency Divider and Time Difference of Arrival

Round 1

Reviewer 1 Report

The authors present a sound source localization method based on the TDOA and include a frequency divider. Whereas the relevance of such a research field is certainly high, the authors fail to acknowledge important references in the field that discuss and compare other advanced acoustic imaging methods. In addition, the format of the equations, symbols, and figures needs to be improved.

In the following, LXX refers to the line number:

L15: In which way do sound source localization methods increase safety? Please explain.

L18: There should be a space between method and (GCC). There are a lot of mistakes like this throughout the paper, please correct.

L53: When describing previous applications of acoustic imaging methods in practical cases and advanced methods like MUSIC, please refer to the following review papers too as they include a very extensive list of state-of-the-art methods and their performance in useful applied cases:

[1] Merino-Martinez, R., et al., “A review of acoustic imaging methods using phased microphone arrays,” CEAS Aeronautical Journal, Vol. 10, No. 1, pp. 197-230,  2019. DOI: 10.1007/s13272-019-00383-4.

[2] Sarradj, E., et al., “A microphone array method benchmarking exercise using synthesized input data,” 23rd AIAA/CEAS Aeroacoustics Conference. 5 - 9 June 2017. Denver, USA. DOI: 10.2514/6.2017-3719.

L61: and so on is an informal expression, please rephrase.

L198: what do you mean "led into the crossover for crossover"?

L205: All units need to be separated from the number, so instead of 0Hz it should be 0 Hz. Please correct throughout the paper.

L213: After respectively, there should be a comma and not a full stop.

L214: lg should read log

L215: the parentheses are too small, please adapt.

Fig 2.2. - The y-axis should read log and include the units in both axes (dB?)

L253: Instead of left branch, it should be lower branch.

Fig 3.3 - in the middle of the chart Tableto should read Table to.

The English level needs to be improved throughout the paper. I include some corrections in the list of comments, but I suggest to have a native English speaker revising the paper before resubmission.

Author Response

Thanks for the reviewer’s kind suggestion, your suggestion is of great value to the revision of our paper. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:

L15: Sound source localization, as a passive localization technique, offers greater safety and convenience than other localization techniques such as active emission of electromagnetic waves. This has been modified in the paper.

L18: We correct the issue within the context of the full paper.

L53: Our summary of advanced methods in the research area of this paper does have a slight problem, and we have added the relevant content of the pair based on the review comments. Many thanks.

L61: Yes, we replaced it with etc.

L198: Sorry. Here our formulation is not clear, we have made changes. It should be “led into the frequency divider separated by frequency”.

L205: We have separated the numbers and units throughout the article with spaces. Thank you.

L213-L215:  Sorry. They were oversights on our part and we have made the appropriate changes. 

Fig 2.2. We have corrected the incorrect writing and added the corresponding units for both axes, where the x-axis is in dB and the y-axis is in B.

L253: We have corrected it. Thank you.

Fig 3.3: We took note of this and made changes to the issue accordingly.

We apologise for the typographical and grammatical errors in this manuscript. We have carefully checked the full text and we have asked a native speaker to review the grammar of the words in the full manuscript, and have carefully proofread the changes.

Reviewer 2 Report

See comment in the attached file

Comments for author File: Comments.pdf

Author Response

Thank you very much for your comments concerning our manuscript. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. 

Minor corrections

1. We noticed that, and have added the definition of this function in the text.
2. We have added a detailed analysis near Eq. (2-4).
3. Sorry, we described the definition before Eq. (2-4).
4. Yes, we have added the relevant explanation between Eq. (2-6) and Eq. (2-7).
5. Here our formulation is not clear, we have made changes. It should be “led into the frequency divider separated by frequency”.
6. Sorry for thre oversight and we have made the appropriate changes.
7. Sorry for the confusion. That was a spelling error and we have removed the extra r.

Reviewer 3 Report

The manuscript has been well written establishing novelty in the field. The proposed method introduces a frequency divider during pre-processing and filtering. A modified "minimum sphere method" is used to determine the coordinates of sound sources. the results are compared with other methods. However, it has been repeatedly mentioned the microphone is a receiver, please review if correction is needed.

English is ok

Author Response

Thank you for your kind comments. But in our study it was the sound waves received by the microphone that were used as the system input, and from that point of view, the microphone is indeed the receiver.