Table of contents 
Abstract 
Previous works have found that generating coherent raw audio waveforms with GANs is challenging. In this paper, we show that it is possible to train GANs reliably to generate high quality coherent waveforms by introducing a set of architectural changes and simple training techniques. Subjective evaluation metric (Mean Opinion Score, or MOS) shows the effectiveness of the proposed approach for high quality mel-spectrogram inversion. To establish the generality of the proposed techniques, we show qualitative results of our model in speech synthesis, music domain translation and unconditional music synthesis. We evaluate the various components of the model through ablation studies and suggest a set of guidelines to design general purpose discriminators and generators for conditional sequence synthesis tasks. Our model is non-autoregressive, fully convolutional, with significantly fewer parameters than competing models and generalizes to unseen speakers for mel-spectrogram inversion. Our pytorch implementation runs at more than 100x faster than realtime on GTX 1080Ti GPU and more than 2x faster than real-time on CPU, without any hardware specific optimization tricks. Blog post with samples and accompanying code coming soon.
Results 
Spectrogram Inversion on Unseen Speakers 
Original
   
   
   
   
   
   
   
   
Reconstructed
   
   
   
   
   
   
   
   
End-to-end text-to-speech examples 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
Unconditional Music Synthesis 
Original
   
   
   
   
Reconstructed
   
   
   
   
Sampled
   
   
   
   
   
   
   
   
Music Translation 
Example for source domain: Bach Solo Cello
Beethoven accompanied violin 
Beethoven solo piano 
 
 Original 
 Mor et al. 2019 
 Ours 
 Mor et al. 2019 
 Ours 
 
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Samples along Training 
50 epochs - 1.35 hours
   
100 epochs - 2.71 hours
   
200 epochs - 5.42 hours
   
400 epochs - 10.84 hours
   
800 epochs - 21.68 hours
   
1600 epochs - 43.36 hours
   
3200 epochs - 86.72 hours
   
Ablation 
original
   
   
Baseline
   
   
l1_observed_no_feat_match
   
   
l1_observed_space
   
   
no_dilations
   
   
no_group_disc
   
   
no_multiscale_disc
   
   
no_patch_gan
   
   
no_weight_norm
   
   
spectral_norm