In the previous chapters, we've been generating symbolic content such as MIDI. In this chapter, we'll be looking at generating sub-symbolic content, such as raw audio. We'll be using the Waveform Audio File Format (WAVE or WAV, stored in a .wav file), a format containing uncompressed audio content, usable on pretty much every platform and device. See Chapter 1, Introduction on Magenta and Generative Art, for more information on waveforms in general.
Generating raw audio using neural nets is a rather recent feat, following the 2016 WaveNet paper, A Generative Model For Raw Audio. Other network architectures also perform well in audio generation, such as SampleRNN, also released in 2016 and used since to produce music tracks and albums (see databots for an example).
As stated in Chapter 2, Generating Drum Sequences...