Titan sub - audio released

[GregLocock]

The Titan Submersible Coast Guard Marine Board of Investigation releases audio recording

A National Oceanic and Atmospheric Administration (NOAA) moored passive acoustic recorder, approximately 900 miles from the Titan submersible implosion site, records the suspected acoustic signature of the Titan submersible implosion, June 18, 2023. The U.S. Coast Guard’s Titan Marine Board of...

www.dvidshub.net

I haven't found a decent quality sound file of this, but they have at least run a spectrogram, showing alot of activity 0-100 Hz and around 230 Hz, the latter having a wavelength of 6.5m, similar to the length of the hull at 6.7m. I suspect higher harmonics might give some more clues.

 

[analogkid2digitalman]

Curious, why the long tail of the 0-100Hz components?

-AK2DM

 

[LittleInch]

Sound reflections off the Titanic?

 

[analogkid2digitalman]

I wonder if it has to do with reverberation (in Wiki link) and that the VLF band of 1-100Hz travels for very long distances (2nd link)?

Underwater acoustics - Wikipedia

en.wikipedia.org

https://faculty.washington.edu/wilcock/files/PaperPDFs/wilcocketal_annrev_2014.pdf

-AK2DM

 

[GregLocock]

Here's a wav file, and a better plot of the waveform. I don't know if the clipping is an artefact of the mp4 to wav converter I used, but this is pretty dodgy looking timehistory, the jumps in amplitude at 7 and 22s are suspicious. Comparing it with the time history in the video I'm tempted to say it's a rubbish conversion.

 

[GregLocock]

Well, the problem is the released mp4 file has the jumps in gain, and clipping, the displayed waveform in the first post is NOT of the audio in the mp4. That's rather annoying.

 

[dik]

I'm surprised it took that long...

 

[LittleInch]

Remember this sensor was 900 HUNDRED miles away. That's got to have an impact on the sound waves.

Relection off the surface can make it elongate as well.

This event was over in milliseconds.

 

[GregLocock]

Yes. the trick would be to do a wavelet analysis, but given the rubbish quality of the mp4 audio (clipped and gain fiddled with) I'm not going to be bothering with any great enthusiasm (and alright I'm not having any success with downloading the signal analysis package for Octave).

Multiple path demodulation is used in seismology and seismic surveys, and sometimes in cars for that matter.

The other issue is that higher frequencies are attenuated far more than lower frequencies