Audio Features for a Track

[charofisch]

Plan

Free/Premium

Country

Device

(iPhone 8, Samsung Galaxy 9, Macbook Pro late 2016)

Operating System

(iOS 10, Android Oreo, Windows 10,etc.)

My Question or Issue

Hello!

I am writing a math paper using data from the "Get Audio Features for a Track" page (linked below).

https://developer.spotify.com/console/get-audio-features-track/?id=11dFghVXANMlKmJXsNCbNl

I was wondering if anyone has more specific details about the way Spotify chose to measure each metric (danceability, valence, energy, loudness, and acousticness). I'm particularly curious about the loudness, why does it use negative decibels? I have information from this page: https://developer.spotify.com/documentation/web-api/reference/#object-audiofeaturesobject

but if someone could offer more clarity into how Spotify determined and measured each metric, it would be appreciated!

[lonetrack]

Years later, I now wonder the same exact thing as you, even specifically about the loudness metric. How does Spotify measure loudness here? A good guess would be to assume that it's the ITU 1770 standard they use for loudness normalization, but without any formal definitions it's unusable.