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Christian Battaglia
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Neural Networking Audio Analyses

Ongoing notes on neural network fundamentals and how they apply to audio analysis — from feedforward networks to radial basis functions, building toward understanding how Spotify's Discover Weekly works under the hood.
Christian Battaglia

Christian Battaglia

September 16, 2019

2 min read

neural networks
audio analysis
Spotify
machine learning
Discover Weekly
feedforward
radial basis

An ongoing exploration into neural networks with the end goal of understanding audio analysis at a deeper level. These are living notes — definitions, network types, and the building blocks for eventually applying ML to music data.

intro to neural networks

definitions

features:

weights:

activation function:

  • we add positive features and subtract negative features multiplied by their weight
  • have to pick a normalization function too (i.e. sigmoid, etc)

neuron:

  1. takes the inputs and multiplies them by their weights
  2. sums them up
  3. applies the activation function to the sum

types

feedforward

  • data passes through the different input nodes till it reaches the output node
    • moves in only one direction from the first tier onwards until it reaches the output node
    • this is also known as a front propagated wave which is usually achieved by using a classifying activation function
  • the sum of the products of the inputs and their weights are calculated

radial basis

  • distance of any point relative to the centre
  • 2 layers
    • inner: the features are combined with the radial basis function
    • output of these features is taken into account when calculating the same output in the next time-step