# Why do we have negative sign dB in spectrum in audacity?

I am trying to understand the spectrum of the sound of a cuckoo. It is 13-second audio clip and its download link is

https://file.io/d4nqddrb1NNY

Actually, I have a confusion, I have attached a snap of research gate where sound levels are mentioned with + db sign. I have also attached a snap of the spectrum of this audio that I got in Audacity. Why do we have a negative sign here with dB values? Shouldn't it be a positive sign like the values shown on researchgate?

• This has to do with scaling. It quite often depends on the Fourier Transform implementation too. Moreover, most probably, what you see there is in dBFS (Full Scale), which is quite widely used in digital systems. The dBFS scale is a logarithmic scale (hence the dB) with its maximum reaching out to 0, with it being the maximum peak attainable value of the digital system. Thus, all values but the maximum have negative values (since the fraction in the logarithm has the maximum value in the denominator and it is always but for the highest value negative). Aug 8, 2023 at 10:05
• No, it should not be a positive sign, LECS. How do you arrive at the conclusion that it should? Aug 8, 2023 at 11:42
• Does this answer your question? What is the audible level for digital audio dB units? Aug 8, 2023 at 12:20
• Regarding your latest update: these are dB(A), meaning they are dB SPL (referenced to 20 micropascals, see Justme’s answer), but “A-weighted” to account for humans perception of loudness. You would benefit from a good read on decibels and the different measures used (dBSPL, dBFS, dBA, dBu etc). Google is your friend for this one.
– Jdip
Aug 9, 2023 at 9:16