[SciPy-User] scipy.signal.spectrogram level in DB

[me at fredt.org]

Thanks for your input. However, I should have been more clear, I meant 
the spectrum view like here: 
http://manual.audacityteam.org/man/plot_spectrum.html

If I do a spectrogram and look at a time interval, I should be able to 
get the same view however, getting the same scale seems to be a 
challenge. Perhaps the solution is in what you provided but in this case 
the np.max would be a static number?

On 2017-12-12 19:52, David Nicholson wrote:
> I think at a very high level to convert to dB you would do:
> 
> 20 * np.log10 ( your_spectrogram / np.max(your_spectrogram))
> 
> Apparently Audacity uses dBFS so to get the exact same thing as
> Audacity, you would need to know what Audacity thinks the maximum peak
> value of amplitude is and then put that in place of
> np.max(your_spectrogram)
> 
> http://wiki.audacityteam.org/wiki/HowAudacityWorks [2]
> 
> https://en.wikipedia.org/wiki/DBFS [3]
> 
> That's my best guess but someone who knows more digital signal
> processing might be able to give you a better answer
> 
> On Tue, Dec 12, 2017 at 8:33 PM, <me at fredt.org> wrote:
> 
>> Hi, does anyone how to convert the power level in DB out of
>> scipy.signal.spectrogram? I'm trying to match what I see in audacity
>> in term of spectral power at various frequency.
>> 
>> Thanks
>> FredT
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> 
> --
> 
> David Nicholson, Ph.D.
> Sober Lab [4], Emory Neuroscience Program. [5]
> 
> www.nicholdav.info; [6]https://github.com/NickleDave [7]
> 
> 
> Links:
> ------
> [1] https://mail.python.org/mailman/listinfo/scipy-user
> [2] http://wiki.audacityteam.org/wiki/HowAudacityWorks
> [3] https://en.wikipedia.org/wiki/DBFS
> [4] http://www.biology.emory.edu/research/Sober/Home.html
> [5] http://www.emory.edu/NEUROSCIENCE/
> [6] http://www.nicholdav.info
> [7] https://github.com/NickleDave
> 
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