<p>The fuzzy noise near 0Hz indicates instrument noise to me at first glance. I'd zoom in much further on that to see if there is a strong fundamental frequency.</p>

CC BY-SA 4.0
2022-07-28T07:02:54.120Z
I agree that there seems to be some low-freq noise which is coincident with the other sound, but surely we do already see a strong fundamental frequency, starting at ~150 Hz?
Dan Stowell
CC BY-SA 4.0
2022-07-28T14:12:43.540Z
@DanStowell I agree the noise <150Hz is probably not the fundamental, but in my experience sometimes zooming in and changing the FFT size can make what looks like noise in higher frequencies actually resemble a super low tonal signal. Not that I am confident this is the case here, just the sort of due diligence I'd recommend to evaluate if this could be a tonal call versus noise.
Dan Woodrich
CC BY-SA 4.0
2022-07-27T18:37:15.437Z
2022-07-27T18:37:15.437Z
Dan Woodrich
<p>I am trying to learn the source of the sound in the spectrogram below. It has been recorded in early to late winter (January/February) on the shelf (25 m depth) off the US state of Georgia in the Western North Atlantic. There appears to be stacked harmonics that are frequency modulated. Audibly, they sound like they may originate from a marine mammal in my opinion. Any assistance would be appreciated.
<a href="https://i.sstatic.net/bXp7k.png" rel="noreferrer"><img src="https://i.sstatic.net/bXp7k.png" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2022-07-27T20:18:58.670Z
Can you add few more details about the recording? Can you link to an audio recording so we can listen to it? Also what time of day was it?
angie_zorka
<marine-species><water><marine-mammals><mystery-sound>
Mystery Marine Animal Sound off Georgia USA in Western Atlantic
# Mystery Marine Animal Sound off Georgia USA in Western Atlantic

(Asked by: username_0 on 2022-07-27)

I am trying to learn the source of the sound in the spectrogram below. It has been recorded in early to late winter (January/February) on the shelf (25 m depth) off the US state of Georgia in the Western North Atlantic. There appears to be stacked harmonics that are frequency modulated. Audibly, they sound like they may originate from a marine mammal in my opinion. Any assistance would be appreciated.
[![enter image description here](https://i.sstatic.net/bXp7k.png)](https://i.sstatic.net/bXp7k.png)

**Tags:** marine-species, water, marine-mammals, mystery-sound

> **Comments:**
> **username_1**: Can you add few more details about the recording? Can you link to an audio recording so we can listen to it? Also what time of day was it?  

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## 1 answers

### Answer by username_2 on 2022-07-27. Score: 1

The fuzzy noise near 0Hz indicates instrument noise to me at first glance. I'd zoom in much further on that to see if there is a strong fundamental frequency.

> **Comments:**
> **username_3**: I agree that there seems to be some low-freq noise which is coincident with the other sound, but surely we do already see a strong fundamental frequency, starting at ~150 Hz?  
> **username_2**: @username_3 I agree the noise <150Hz is probably not the fundamental, but in my experience sometimes zooming in and changing the FFT size can make what looks like noise in higher frequencies actually resemble a super low tonal signal. Not that I am confident this is the case here, just the sort of due diligence I'd recommend to evaluate if this could be a tonal call versus noise.  

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