Alpha-Indices on different sampling rates

[Ramona Mattmüller]

Dear all,

I wanted to ask if anyone has experience with applying the alpha-indices to audio files with different sampling rates.
I have a large dataset of marine sound recordings over several years. However, different recording devices and different sampling rates were used. I would like to calculate the indices for all these data to make comparisons across regions and time. However, I wonder if applying a bandpass filter is sufficient or do I need to decimate all the files with high sampling rates to the smallest sampling rate applied to get comparable index values? But I think I need to decimate the data first since the time and frequency resolution depend on the sampling rate.
I hope someone would like to share their ideas or thoughts on this.

The idea is to calculate the indices broadband, and the range of interest is 10 - 840 Hz and 10 - 3 428 Hz.


Any help would be greatly appreciated. Thanks a lot.
All the best,
Ramona

[Jérôme SUEUR]

Dear Ramona,

Yes this is definitely advised to compare files that have the same sampling rate as most of the indices are based on the Fourier transform which time*freq resolution depends on the sampling rate.

HTH

Jerome

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De: "Ramona Mattmüller" <r.m.mat...@gmail.com>
À: "seewave GROUP" <see...@googlegroups.com>
Envoyé: Jeudi 12 Octobre 2023 17:36:52
Objet: [seewave] Alpha-Indices on different sampling rates

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[Ramona Mattmüller]

Dear Jerome,

thank you for your fast response! That is what I assumed, but it's good to have it confirmed.

All the best,
Ramona