Acoustic Analysis of Fish Tanks for Marine Bioacoustics Research
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsPlease add references to the equations.
Put parameters of the source and receiver (sensitivity, frequency characteristics..)
Add absolute values not in dB to see what is the pressure range...what is the level of hydrophone self noise...
Figure 3 is not visible..
Maybe reflectogram in each different position cluld be added as in room acoustics..but you need simulations in time domain..is it possible to have?
the self noise of recording system shluld be mentioned and estimation of signal to noise ratio when this signals would be recorded...
Directivity pattern of transducer also hav einfluence on obtained pressure distribution..so please discuss this..
Add some new parameters of the tank ..reverberation time in tank...at each frequency...at different position maybe if possible...and when new absorption materiuals would be added on tank surfaces..
Author Response
The authors would like to acknowledge the suggestions made by the reviewer and the readiness to revise the work. All suggestions and comments have been considered; modifications made accordingly (blue color font text in the revised manuscript).
Comments 1: Please add references to the equations.
Response 1: Both the equations in the main text and the Appendix correspond to the analytical model proposed by Novak et al. as referred throughout the whole paper, with slight modifications on the nomenclature for a more compact and simpler recall thereof.
Comments 2: Put parameters of the source and receiver (sensitivity, frequency characteristics..)
Response 2: The most representative parameters of the receiver (hydrophone AQUARIAN AS-1) were included in Section 3.2 in the revised manuscript. As for the custom-made sound source, a rigorous characterization thereof to determine its sensitivity and the directional response would require performing the experiments in free field conditions or in an anechoic tank, which unfortunately is not available for the authors now. Alternatively, the sensitivity frequency response was measured in air as depicted in Figure 1.R. Given that the design and development of this sound source are currently under a patent process, the authors would like to ask the reviewer not to request us to include it in the revised manuscript. Thank you very much for your understanding.
Comments 3: Add absolute values not in dB to see what is the pressure range...what is the level of hydrophone self noise...
Response 3: The dynamic range of sound pressure field in the fish tank experiments was from 100 μPa (40 dB re 1 μPa) to 0.263 Pa (108.4 dB re 1 μPa). As for the hydrophone, self-noise calibration data for AS-1 was not available, so background noise was recorded inside the fish tank in the absence of any sound source (see updated Figure 2.b in the revised manuscript). Experiments show that the sound source yields sound pressure levels far above (at least 10 dB) the background noise in the frequency range of analysis. Both the above data and the previous discussion were included in the revised manuscript.
Comments 4: Figure 3 is not visible.
Response 4: It seems that some figures were scaled down in the word-to-pdf conversion process after our submission to the Editorial Office. We ask the reviewer to please check the Word document in case the problem persists in the revised manuscript. Thank you very much and sorry for the inconvenience.
Comments 5: Maybe reflectogram in each different position cluld be added as in room acoustics..but you need simulations in time domain..is it possible to have?
Response 5: The authors would like to thank the reviewer for suggesting the inclusion of a reflectogram to analyze the reflection phenomena inside the fish tank. In fact, the authors are currently working not only on the analysis of reverberation time but also on the use of water-compatible materials on the fish tank surfaces to minimize it. Figure 2.R shows the decay curves for different octave bands and all the measurement points inside the tank for the reference configuration. The authors would like to please ask the reviewer not to request us to include it in the revised manuscript, as this is part of a more in-depth analysis of another ongoing work. Thank you very much for your understanding.
Comments 6: the self noise of recording system shluld be mentioned and estimation of signal to noise ratio when this signals would be recorded...
Response 6: As for the self-noise and SNR of the recording system, according to the specifications provided by the manufacturers, the SHURE PS1A phantom power supply has a maximum self-noise in differential mode of 1.78μV (20 to 20 kHz range). For the NEXUS 2692 signal conditioner working with gains below 40 dB, the self-noise is lower than 0.01%. Finally, the NI-USB-6351 working in a dynamic range of 10 V yields a random noise of 281 μV rms. All this data was included in the revised manuscript.
Comments 7: Directivity pattern of transducer also hav einfluence on obtained pressure distribution..so please discuss this..
Response 7: Indeed, the reviewer is correct, and the directivity of the sound source may influence the sound pressure spatial distribution. However, given that the dimensions of the fish tank are close to or below the wavelengths of interest, and the sound field spatial distribution was measured spaced away from the sound source and in steady-state conditions (i.e. reverberant field dominates over direct field), the directional features of the sound source may not have a significant influence on the resulting sound field. This discussion was added in Section 3.2 in the revised manuscript.
Comments 8: Add some new parameters of the tank ..reverberation time in tank...at each frequency...at different position maybe if possible...and when new absorption materiuals would be added on tank surfaces..
Response 8: These points were answered in one of the previous questions.
Reviewer 2 Report
Comments and Suggestions for Authors This study proposes an innovative theoretical experimental combined analysis method for the uncertainty of fish tank sound field in aquatic acoustics experiments, which has important application value. The author successfully constructed a Novak analytical model considering wall damping and independently developed a high-precision robot measurement system, achieving high-resolution spatial scanning of the horizontal acoustic field of the fish tank (252 measurement points/plane). The method is rigorous and reproducible. The research system reveals the dependence of sound field distribution on frequency, water level, and depth, providing a key basis for the standardization of bioacoustic experimental design. The following modifications should be made to the paper before publication: The Novak model needs to consider the influence of wall bending vibration in the low frequency range (such as the 125 Hz case mentioned in section 4.4), but its applicable frequency domain upper limit is not specified. Suggest adding frequency boundaries for model validation (such as Schroeder cut-off frequency) and discussing modeling errors for high-frequency modal leakage effects (such as whether the transmission loss of the glass wall can be ignored when>10 kHz). ​​ 2. The experiment resulted in blind spots caused by the obstruction of the sound source/hydrophone bracket (Section 3.2), but its impact on the accuracy of modal reconstruction was not evaluated. It is recommended to quantify the spatial interpolation error of sound pressure level (such as RMS error dB value) by comparing the blind spot interpolation data with the complete plane simulation, or indicate the interference risk of blind spot location on the distribution of specific modal nodes (such as (4,1,1)). 3. The frequency response curve of the custom sound source (TEAX19C01-8 driver) is not provided. It is necessary to supplement the emission voltage response spectrum (TVR) of the sound source in the range of 1-10 kHz and verify its piston vibration assumption (such as laser vibrometer data), otherwise the power gain analysis in Figure 6 may be affected by nonlinear distortion of the sound source. Refined Structure Acoustic Coupling Discussion 4. There are many images in the paper that are too small to be seen clearly. The authors should carefully check and revise them to ensure that the images have appropriate size and resolution of not less than 300 * 300dpi.Author Response
This study proposes an innovative theoretical experimental combined analysis method for the uncertainty of fish tank sound field in aquatic acoustics experiments, which has important application value. The author successfully constructed a Novak analytical model considering wall damping and independently developed a high-precision robot measurement system, achieving high-resolution spatial scanning of the horizontal acoustic field of the fish tank (252 measurement points/plane). The method is rigorous and reproducible. The research system reveals the dependence of sound field distribution on frequency, water level, and depth, providing a key basis for the standardization of bioacoustic experimental design. The following modifications should be made to the paper before publication:
The authors would like to acknowledge the suggestions made by the reviewer and the readiness to revise the work. All suggestions and comments have been considered; modifications made accordingly (blue color font text in the revised manuscript).
Comments 1: The Novak model needs to consider the influence of wall bending vibration in the low frequency range (such as the 125 Hz case mentioned in section 4.4), but its applicable frequency domain upper limit is not specified. Suggest adding frequency boundaries for model validation (such as Schroeder cut-off frequency) and discussing modeling errors for high-frequency modal leakage effects (such as whether the transmission loss of the glass wall can be ignored when>10 kHz).​​
Response 1: The authors would like to thank the reviewer for pointing out the limitations of the Novak et al. model regarding bending vibration and frequency range of application. Establishing the frequency boundaries for model validation would require on the one hand a knowledge of the distribution of vibration modes over the fish tank walls so that if the modal density is high enough, the system can be analyzed using alternative approaches such as the Statistical Energy Analysis (SEA) method. Given that in our study, the bending vibrations have a much lower contribution in terms of total acoustic energy in the water when compared to the normal modes (see Figures 2,4,5,6, and 8 in the manuscript), these effects were neglected in the theoretical model, even though further research on this issue is currently being carried out by the authors. As for the high-frequency limit, since the sound pressure field in the fish tank involves more superimposed normal modes as the frequency increases, it will be determined by the number of modal indexes considered for the modal summation in the Novak et al. model. In our work, the maximum values for these indexes were chosen so that convergence was found for the sound pressure spectrum in the frequency range under analysis. Alternatively, Schroeder frequency cut-off frequency can be calculated from reverberant behavior (see Figure 2.R showing the decay curves for different octave bands at all the measurement points inside the fish tank for the reference configuration), or extra effects such as glass leakage at frequencies above 10 kHz included in the damping factor. The above discussions were included in Sections 4.1 and 4.4 in the revised manuscript, except the decay curves, as these are part of a more in-depth analysis in another ongoing work. Thank you very much for your understanding.
Comments 2: The experiment resulted in blind spots caused by the obstruction of the sound source/hydrophone bracket (Section 3.2), but its impact on the accuracy of modal reconstruction was not evaluated. It is recommended to quantify the spatial interpolation error of sound pressure level (such as RMS error dB value) by comparing the blind spot interpolation data with the complete plane simulation, or indicate the interference risk of blind spot location on the distribution of specific modal nodes (such as (4,1,1)).
Response 2: Indeed, the reviewer is correct, and some blind spots are caused by the obstruction of both the sound source and the hydrophone, which may therefore influence the resulting sound field. However, it should be noted that not only are the dimensions of the fish tank close or below the wavelengths of interest, but the sound field spatial distribution was measured spaced away from the sound source and in steady-state conditions (i.e. reverberant field dominates over direct field). Besides, a good agreement can be found between the analytical and experimental results, the accuracy being slightly reduced at the highest modes analyzed due to the spatial resolution used in the experiments (which could also be increased but herein served to illustrate most of the modal shapes). A discussion on this point was added in Section 3.3 and Section 4.1 (before Figure 3).
Comments 3: The frequency response curve of the custom sound source (TEAX19C01-8 driver) is not provided. It is necessary to supplement the emission voltage response spectrum (TVR) of the sound source in the range of 1-10 kHz and verify its piston vibration assumption (such as laser vibrometer data), otherwise the power gain analysis in Figure 6 may be affected by nonlinear distortion of the sound source.
Response 3: The emission voltage response spectrum of the sound source used in the experiments is attached in file Figure 1.R. Given that the design and development of this sound source (including its vibrational characterization) is currently under a patent process, the authors would like to please ask the reviewer not to request us to include it in the revised manuscript. Thank you very much for your understanding.
Comments 3.b: Refined Structure Acoustic Coupling Discussion
Response 3.b: Some extra comments regarding the structural-acoustic coupling were included in Section 4.4 in the revised manuscript.
Comments 4: There are many images in the paper that are too small to be seen clearly. The authors should carefully check and revise them to ensure that the images have appropriate size and resolution of not less than 300 * 300dpi.
Response 4: The authors would like to apologize as it seems that some figures were scaled down in the word-to-pdf conversion process after our submission to the Editorial Office. We ask the reviewer to please check the Word document in case the problem persists in the revised manuscript. Thank you very much for your understanding and sorry for the inconvenience that it may have caused.
Reviewer 3 Report
Comments and Suggestions for AuthorsAcoustic analysis of fish tanks for marine bioacoustics research - jmse-3673837- by Carbajo et al.
The study involves an in-depth acoustic analysis of aquariums commonly used for bioacoustic research. Predictions using the theoretical approach and experimental measurements with a robotic system were performed to study the spatial distribution of the sound field under aquarium conditions. The study would be interesting and could be of great help in understanding sound fields and in the improvement phase of designing passive solutions to reduce anthropogenic noise as well as control the sound field in aquariums and offshore basins. However, the paper is not yet in MDPI format. However, the paper is not yet in MDPI format. It is difficult to provide an opinion at this stage. I encourage the authors to rewrite and resubmit their article.
L21-30 The aim of the study and specific objectives should be clearly mentioned before presenting the structure of the paper.
In the main text (L22-357) and in the list of references (L358-431), authors should consult the MDPI guide for citation and author list creation.
Figs. 3 and 7 are illegible.
Fig. 8 is missing.
Author Response
The study involves an in-depth acoustic analysis of aquariums commonly used for bioacoustic research. Predictions using the theoretical approach and experimental measurements with a robotic system were performed to study the spatial distribution of the sound field under aquarium conditions. The study would be interesting and could be of great help in understanding sound fields and in the improvement phase of designing passive solutions to reduce anthropogenic noise as well as control the sound field in aquariums and offshore basins.
The authors would like to acknowledge the suggestions made by the reviewer and the readiness to revise the work. All suggestions and comments have been considered; modifications made accordingly (blue color font text in the revised manuscript).
Comments 1: However, the paper is not yet in MDPI format. It is difficult to provide an opinion at this stage. I encourage the authors to rewrite and resubmit their article.
Response 1: The authors would like to apologize as it seems that some figures were scaled down in the word-to-pdf conversion process after our submission to the Editorial Office. We ask the reviewer to please check the word document in case the problem persists in the revised manuscript. Thank you very much for your understanding and sorry for the inconvenience that it may have caused.
Comments 2: L21-30 The aim of the study and specific objectives should be clearly mentioned before presenting the structure of the paper.
Response 2: The authors would like to thank the reviewer for pointing out the necessity of mentioning the specific objectives of our work. Both the aim and specific objectives are now listed in the Introduction of the revised manuscript.
Comments 3: In the main text (L22-357) and in the list of references (L358-431), authors should consult the MDPI guide for citation and author list creation.
Response 3: Indeed, the reviewer is correct as the references did not follow the author guidelines of the journal. Both the citation and author list creation were corrected in the revised manuscript.
Comments 4: Figs. 3 and 7 are illegible.
Response 4: Same answer as to the first question.
Comments 5: Fig. 8 is missing.
Response 5: Same answer as to the previous question.
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsIt can be accepted.
Reviewer 3 Report
Comments and Suggestions for AuthorsAcoustic analysis of fish tanks for marine bioacoustics research - jmse-3673837-R1- by Carbajo et al.
I had the opportunity to reread the revised version of Carbajo et al.’s paper - jmse-3673837-R1. This version seems better presented and elaborated. The authors answered all the questions I had. It is clearer for readers. I must congratulate the authors for the efforts made to improve the paper. In my opinion, it can therefore be published in jmse.
