Flowtron has Mean Opinion Scores (MOS) comparable to state of the art text to speech models. Here we provide a sample from Flowtron and Tacotron 2 trained on the LJSpeech dataset.

LJSpeech Ground Truth	Flowtron	Tacotron 2

3.3.1 Sampling the Prior ( Speech Variation )

Flowtron σ²=0
Flowtron σ²=0.5
Flowtron σ²=1
Tacotron 2 p=0.5

3.3.2 Sampling the Prior ( Interpolation between samples )

	1/100	30/100	60/100	100/100
Flowtron same speaker

Flowtron model without speaker embeddings. We interpolate between z-vectors producing speech from Sally and Helen with the phrase "We are testing this model".

	100% Helen	66% Helen 33% Sally	33% Helen 66% Sally	100% Sally
Flowtron different speakers

3.4.1 Sampling the Posterior ( Seen speaker )

Flowtron Style Transfer over time

Flowtron Style Transfer over time

Flowtron Posterior	posterior expressive ratio4 seq0 sample0 posterior expressive ratio4 seq0 sample1 posterior expressive ratio4 seq0 sample2 posterior expressive ratio4 seq0 sample3 posterior expressive ratio4 seq0 sample4 posterior expressive ratio4 seq0 sample5 posterior expressive ratio4 seq0 sample6 posterior expressive ratio4 seq0 sample7 posterior expressive ratio4 seq0 sample8 posterior expressive ratio4 seq0 sample9 posterior expressive ratio4 seq1 sample0 posterior expressive ratio4 seq1 sample1 posterior expressive ratio4 seq1 sample2 posterior expressive ratio4 seq1 sample3 posterior expressive ratio4 seq1 sample4 posterior expressive ratio4 seq1 sample5 posterior expressive ratio4 seq1 sample6 posterior expressive ratio4 seq1 sample7 posterior expressive ratio4 seq1 sample8 posterior expressive ratio4 seq1 sample9 posterior expressive ratio4 seq2 sample0 posterior expressive ratio4 seq2 sample1 posterior expressive ratio4 seq2 sample2 posterior expressive ratio4 seq2 sample3 posterior expressive ratio4 seq2 sample4 posterior expressive ratio4 seq2 sample5 posterior expressive ratio4 seq2 sample6 posterior expressive ratio4 seq2 sample7 posterior expressive ratio4 seq2 sample8 posterior expressive ratio4 seq2 sample9 posterior expressive ratio4 seq3 sample0 posterior expressive ratio4 seq3 sample1 posterior expressive ratio4 seq3 sample2 posterior expressive ratio4 seq3 sample3 posterior expressive ratio4 seq3 sample4 posterior expressive ratio4 seq3 sample5 posterior expressive ratio4 seq3 sample6 posterior expressive ratio4 seq3 sample7 posterior expressive ratio4 seq3 sample8 posterior expressive ratio4 seq3 sample9 posterior expressive ratio4 seq4 sample0 posterior expressive ratio4 seq4 sample1 posterior expressive ratio4 seq4 sample2 posterior expressive ratio4 seq4 sample3 posterior expressive ratio4 seq4 sample4 posterior expressive ratio4 seq4 sample5 posterior expressive ratio4 seq4 sample6 posterior expressive ratio4 seq4 sample7 posterior expressive ratio4 seq4 sample8 posterior expressive ratio4 seq4 sample9
Flowtron Baseline	baseline expressive ratio4 seq0 sample0 baseline expressive ratio4 seq0 sample1 baseline expressive ratio4 seq0 sample2 baseline expressive ratio4 seq0 sample3 baseline expressive ratio4 seq0 sample4 baseline expressive ratio4 seq0 sample5 baseline expressive ratio4 seq0 sample6 baseline expressive ratio4 seq0 sample7 baseline expressive ratio4 seq0 sample8 baseline expressive ratio4 seq0 sample9 baseline expressive ratio4 seq1 sample0 baseline expressive ratio4 seq1 sample1 baseline expressive ratio4 seq1 sample2 baseline expressive ratio4 seq1 sample3 baseline expressive ratio4 seq1 sample4 baseline expressive ratio4 seq1 sample5 baseline expressive ratio4 seq1 sample6 baseline expressive ratio4 seq1 sample7 baseline expressive ratio4 seq1 sample8 baseline expressive ratio4 seq1 sample9 baseline expressive ratio4 seq2 sample0 baseline expressive ratio4 seq2 sample1 baseline expressive ratio4 seq2 sample2 baseline expressive ratio4 seq2 sample3 baseline expressive ratio4 seq2 sample4 baseline expressive ratio4 seq2 sample5 baseline expressive ratio4 seq2 sample6 baseline expressive ratio4 seq2 sample7 baseline expressive ratio4 seq2 sample8 baseline expressive ratio4 seq2 sample9 baseline expressive ratio4 seq3 sample0 baseline expressive ratio4 seq3 sample1 baseline expressive ratio4 seq3 sample2 baseline expressive ratio4 seq3 sample3 baseline expressive ratio4 seq3 sample4 baseline expressive ratio4 seq3 sample5 baseline expressive ratio4 seq3 sample6 baseline expressive ratio4 seq3 sample7 baseline expressive ratio4 seq3 sample8 baseline expressive ratio4 seq3 sample9 baseline expressive ratio4 seq4 sample0 baseline expressive ratio4 seq4 sample1 baseline expressive ratio4 seq4 sample2 baseline expressive ratio4 seq4 sample3 baseline expressive ratio4 seq4 sample4 baseline expressive ratio4 seq4 sample5 baseline expressive ratio4 seq4 sample6 baseline expressive ratio4 seq4 sample7 baseline expressive ratio4 seq4 sample8 baseline expressive ratio4 seq4 sample9
Tacotron GST	gst expressive seq0 sample0 gst expressive seq0 sample1 gst expressive seq0 sample2 gst expressive seq0 sample3 gst expressive seq0 sample4 gst expressive seq0 sample5 gst expressive seq0 sample6 gst expressive seq0 sample7 gst expressive seq0 sample8 gst expressive seq0 sample9 gst expressive seq1 sample0 gst expressive seq1 sample1 gst expressive seq1 sample2 gst expressive seq1 sample3 gst expressive seq1 sample4 gst expressive seq1 sample5 gst expressive seq1 sample6 gst expressive seq1 sample7 gst expressive seq1 sample8 gst expressive seq1 sample9 gst expressive seq2 sample0 gst expressive seq2 sample1 gst expressive seq2 sample2 gst expressive seq2 sample3 gst expressive seq2 sample4 gst expressive seq2 sample5 gst expressive seq2 sample6 gst expressive seq2 sample7 gst expressive seq2 sample8 gst expressive seq2 sample9 gst expressive seq3 sample0 gst expressive seq3 sample1 gst expressive seq3 sample2 gst expressive seq3 sample3 gst expressive seq3 sample4 gst expressive seq3 sample5 gst expressive seq3 sample6 gst expressive seq3 sample7 gst expressive seq3 sample8 gst expressive seq3 sample9 gst expressive seq4 sample0 gst expressive seq4 sample1 gst expressive seq4 sample2 gst expressive seq4 sample3 gst expressive seq4 sample4 gst expressive seq4 sample5 gst expressive seq4 sample6 gst expressive seq4 sample7 gst expressive seq4 sample8 gst expressive seq4 sample9

Flowtron Posterior	posterior highf0 ratio1 seq0 sample0 posterior highf0 ratio1 seq0 sample1 posterior highf0 ratio1 seq0 sample2 posterior highf0 ratio1 seq0 sample3 posterior highf0 ratio1 seq0 sample4 posterior highf0 ratio1 seq0 sample5 posterior highf0 ratio1 seq0 sample6 posterior highf0 ratio1 seq0 sample7 posterior highf0 ratio1 seq0 sample8 posterior highf0 ratio1 seq0 sample9 posterior highf0 ratio1 seq1 sample0 posterior highf0 ratio1 seq1 sample1 posterior highf0 ratio1 seq1 sample2 posterior highf0 ratio1 seq1 sample3 posterior highf0 ratio1 seq1 sample4 posterior highf0 ratio1 seq1 sample5 posterior highf0 ratio1 seq1 sample6 posterior highf0 ratio1 seq1 sample7 posterior highf0 ratio1 seq1 sample8 posterior highf0 ratio1 seq1 sample9 posterior highf0 ratio1 seq2 sample0 posterior highf0 ratio1 seq2 sample1 posterior highf0 ratio1 seq2 sample2 posterior highf0 ratio1 seq2 sample3 posterior highf0 ratio1 seq2 sample4 posterior highf0 ratio1 seq2 sample5 posterior highf0 ratio1 seq2 sample6 posterior highf0 ratio1 seq2 sample7 posterior highf0 ratio1 seq2 sample8 posterior highf0 ratio1 seq2 sample9 posterior highf0 ratio1 seq3 sample0 posterior highf0 ratio1 seq3 sample1 posterior highf0 ratio1 seq3 sample2 posterior highf0 ratio1 seq3 sample3 posterior highf0 ratio1 seq3 sample4 posterior highf0 ratio1 seq3 sample5 posterior highf0 ratio1 seq3 sample6 posterior highf0 ratio1 seq3 sample7 posterior highf0 ratio1 seq3 sample8 posterior highf0 ratio1 seq3 sample9 posterior highf0 ratio1 seq4 sample0 posterior highf0 ratio1 seq4 sample1 posterior highf0 ratio1 seq4 sample2 posterior highf0 ratio1 seq4 sample3 posterior highf0 ratio1 seq4 sample4 posterior highf0 ratio1 seq4 sample5 posterior highf0 ratio1 seq4 sample6 posterior highf0 ratio1 seq4 sample7 posterior highf0 ratio1 seq4 sample8 posterior highf0 ratio1 seq4 sample9
Flowtron Baseline	baseline highf0 ratio1 seq0 sample0 baseline highf0 ratio1 seq0 sample1 baseline highf0 ratio1 seq0 sample2 baseline highf0 ratio1 seq0 sample3 baseline highf0 ratio1 seq0 sample4 baseline highf0 ratio1 seq0 sample5 baseline highf0 ratio1 seq0 sample6 baseline highf0 ratio1 seq0 sample7 baseline highf0 ratio1 seq0 sample8 baseline highf0 ratio1 seq0 sample9 baseline highf0 ratio1 seq1 sample0 baseline highf0 ratio1 seq1 sample1 baseline highf0 ratio1 seq1 sample2 baseline highf0 ratio1 seq1 sample3 baseline highf0 ratio1 seq1 sample4 baseline highf0 ratio1 seq1 sample5 baseline highf0 ratio1 seq1 sample6 baseline highf0 ratio1 seq1 sample7 baseline highf0 ratio1 seq1 sample8 baseline highf0 ratio1 seq1 sample9 baseline highf0 ratio1 seq2 sample0 baseline highf0 ratio1 seq2 sample1 baseline highf0 ratio1 seq2 sample2 baseline highf0 ratio1 seq2 sample3 baseline highf0 ratio1 seq2 sample4 baseline highf0 ratio1 seq2 sample5 baseline highf0 ratio1 seq2 sample6 baseline highf0 ratio1 seq2 sample7 baseline highf0 ratio1 seq2 sample8 baseline highf0 ratio1 seq2 sample9 baseline highf0 ratio1 seq3 sample0 baseline highf0 ratio1 seq3 sample1 baseline highf0 ratio1 seq3 sample2 baseline highf0 ratio1 seq3 sample3 baseline highf0 ratio1 seq3 sample4 baseline highf0 ratio1 seq3 sample5 baseline highf0 ratio1 seq3 sample6 baseline highf0 ratio1 seq3 sample7 baseline highf0 ratio1 seq3 sample8 baseline highf0 ratio1 seq3 sample9 baseline highf0 ratio1 seq4 sample0 baseline highf0 ratio1 seq4 sample1 baseline highf0 ratio1 seq4 sample2 baseline highf0 ratio1 seq4 sample3 baseline highf0 ratio1 seq4 sample4 baseline highf0 ratio1 seq4 sample5 baseline highf0 ratio1 seq4 sample6 baseline highf0 ratio1 seq4 sample7 baseline highf0 ratio1 seq4 sample8 baseline highf0 ratio1 seq4 sample9
Tacotron GST	gst highf0 seq0 sample0 gst highf0 seq0 sample1 gst highf0 seq0 sample2 gst highf0 seq0 sample3 gst highf0 seq0 sample4 gst highf0 seq0 sample5 gst highf0 seq0 sample6 gst highf0 seq0 sample7 gst highf0 seq0 sample8 gst highf0 seq0 sample9 gst highf0 seq1 sample0 gst highf0 seq1 sample1 gst highf0 seq1 sample2 gst highf0 seq1 sample3 gst highf0 seq1 sample4 gst highf0 seq1 sample5 gst highf0 seq1 sample6 gst highf0 seq1 sample7 gst highf0 seq1 sample8 gst highf0 seq1 sample9 gst highf0 seq2 sample0 gst highf0 seq2 sample1 gst highf0 seq2 sample2 gst highf0 seq2 sample3 gst highf0 seq2 sample4 gst highf0 seq2 sample5 gst highf0 seq2 sample6 gst highf0 seq2 sample7 gst highf0 seq2 sample8 gst highf0 seq2 sample9 gst highf0 seq3 sample0 gst highf0 seq3 sample1 gst highf0 seq3 sample2 gst highf0 seq3 sample3 gst highf0 seq3 sample4 gst highf0 seq3 sample5 gst highf0 seq3 sample6 gst highf0 seq3 sample7 gst highf0 seq3 sample8 gst highf0 seq3 sample9 gst highf0 seq4 sample0 gst highf0 seq4 sample1 gst highf0 seq4 sample2 gst highf0 seq4 sample3 gst highf0 seq4 sample4 gst highf0 seq4 sample5 gst highf0 seq4 sample6 gst highf0 seq4 sample7 gst highf0 seq4 sample8 gst highf0 seq4 sample9

3.4.2 Sampling the Posterior ( Unseen speaker style )

Flowtron baseline
Style
Flowtron Style Transfer
Tacotron GST Style Transfer

3.4.3 Sampling the Posterior ( Unseen speaker )

Style
Flowtron Posterior	posterior ravdess ratio1 seq0 sample0 posterior ravdess ratio1 seq0 sample1 posterior ravdess ratio1 seq0 sample2 posterior ravdess ratio1 seq0 sample3 posterior ravdess ratio1 seq0 sample4 posterior ravdess ratio1 seq0 sample5 posterior ravdess ratio1 seq0 sample6 posterior ravdess ratio1 seq0 sample7 posterior ravdess ratio1 seq0 sample8 posterior ravdess ratio1 seq0 sample9 posterior ravdess ratio1 seq1 sample0 posterior ravdess ratio1 seq1 sample1 posterior ravdess ratio1 seq1 sample2 posterior ravdess ratio1 seq1 sample3 posterior ravdess ratio1 seq1 sample4 posterior ravdess ratio1 seq1 sample5 posterior ravdess ratio1 seq1 sample6 posterior ravdess ratio1 seq1 sample7 posterior ravdess ratio1 seq1 sample8 posterior ravdess ratio1 seq1 sample9 posterior ravdess ratio1 seq2 sample0 posterior ravdess ratio1 seq2 sample1 posterior ravdess ratio1 seq2 sample2 posterior ravdess ratio1 seq2 sample3 posterior ravdess ratio1 seq2 sample4 posterior ravdess ratio1 seq2 sample5 posterior ravdess ratio1 seq2 sample6 posterior ravdess ratio1 seq2 sample7 posterior ravdess ratio1 seq2 sample8 posterior ravdess ratio1 seq2 sample9 posterior ravdess ratio1 seq3 sample0 posterior ravdess ratio1 seq3 sample1 posterior ravdess ratio1 seq3 sample2 posterior ravdess ratio1 seq3 sample3 posterior ravdess ratio1 seq3 sample4 posterior ravdess ratio1 seq3 sample5 posterior ravdess ratio1 seq3 sample6 posterior ravdess ratio1 seq3 sample7 posterior ravdess ratio1 seq3 sample8 posterior ravdess ratio1 seq3 sample9 posterior ravdess ratio1 seq4 sample0 posterior ravdess ratio1 seq4 sample1 posterior ravdess ratio1 seq4 sample2 posterior ravdess ratio1 seq4 sample3 posterior ravdess ratio1 seq4 sample4 posterior ravdess ratio1 seq4 sample5 posterior ravdess ratio1 seq4 sample6 posterior ravdess ratio1 seq4 sample7 posterior ravdess ratio1 seq4 sample8 posterior ravdess ratio1 seq4 sample9
Flowtron Baseline	baseline ravdess ratio1 seq0 sample0 baseline ravdess ratio1 seq0 sample1 baseline ravdess ratio1 seq0 sample2 baseline ravdess ratio1 seq0 sample3 baseline ravdess ratio1 seq0 sample4 baseline ravdess ratio1 seq0 sample5 baseline ravdess ratio1 seq0 sample6 baseline ravdess ratio1 seq0 sample7 baseline ravdess ratio1 seq0 sample8 baseline ravdess ratio1 seq0 sample9 baseline ravdess ratio1 seq1 sample0 baseline ravdess ratio1 seq1 sample1 baseline ravdess ratio1 seq1 sample2 baseline ravdess ratio1 seq1 sample3 baseline ravdess ratio1 seq1 sample4 baseline ravdess ratio1 seq1 sample5 baseline ravdess ratio1 seq1 sample6 baseline ravdess ratio1 seq1 sample7 baseline ravdess ratio1 seq1 sample8 baseline ravdess ratio1 seq1 sample9 baseline ravdess ratio1 seq2 sample0 baseline ravdess ratio1 seq2 sample1 baseline ravdess ratio1 seq2 sample2 baseline ravdess ratio1 seq2 sample3 baseline ravdess ratio1 seq2 sample4 baseline ravdess ratio1 seq2 sample5 baseline ravdess ratio1 seq2 sample6 baseline ravdess ratio1 seq2 sample7 baseline ravdess ratio1 seq2 sample8 baseline ravdess ratio1 seq2 sample9 baseline ravdess ratio1 seq3 sample0 baseline ravdess ratio1 seq3 sample1 baseline ravdess ratio1 seq3 sample2 baseline ravdess ratio1 seq3 sample3 baseline ravdess ratio1 seq3 sample4 baseline ravdess ratio1 seq3 sample5 baseline ravdess ratio1 seq3 sample6 baseline ravdess ratio1 seq3 sample7 baseline ravdess ratio1 seq3 sample8 baseline ravdess ratio1 seq3 sample9 baseline ravdess ratio1 seq4 sample0 baseline ravdess ratio1 seq4 sample1 baseline ravdess ratio1 seq4 sample2 baseline ravdess ratio1 seq4 sample3 baseline ravdess ratio1 seq4 sample4 baseline ravdess ratio1 seq4 sample5 baseline ravdess ratio1 seq4 sample6 baseline ravdess ratio1 seq4 sample7 baseline ravdess ratio1 seq4 sample8 baseline ravdess ratio1 seq4 sample9
Tacotron GST	gst ravdess seq0 sample0 gst ravdess seq0 sample1 gst ravdess seq0 sample2 gst ravdess seq0 sample3 gst ravdess seq0 sample4 gst ravdess seq0 sample5 gst ravdess seq0 sample6 gst ravdess seq0 sample7 gst ravdess seq0 sample8 gst ravdess seq0 sample9 gst ravdess seq1 sample0 gst ravdess seq1 sample1 gst ravdess seq1 sample2 gst ravdess seq1 sample3 gst ravdess seq1 sample4 gst ravdess seq1 sample5 gst ravdess seq1 sample6 gst ravdess seq1 sample7 gst ravdess seq1 sample8 gst ravdess seq1 sample9 gst ravdess seq2 sample0 gst ravdess seq2 sample1 gst ravdess seq2 sample2 gst ravdess seq2 sample3 gst ravdess seq2 sample4 gst ravdess seq2 sample5 gst ravdess seq2 sample6 gst ravdess seq2 sample7 gst ravdess seq2 sample8 gst ravdess seq2 sample9 gst ravdess seq3 sample0 gst ravdess seq3 sample1 gst ravdess seq3 sample2 gst ravdess seq3 sample3 gst ravdess seq3 sample4 gst ravdess seq3 sample5 gst ravdess seq3 sample6 gst ravdess seq3 sample7 gst ravdess seq3 sample8 gst ravdess seq3 sample9 gst ravdess seq4 sample0 gst ravdess seq4 sample1 gst ravdess seq4 sample2 gst ravdess seq4 sample3 gst ravdess seq4 sample4 gst ravdess seq4 sample5 gst ravdess seq4 sample6 gst ravdess seq4 sample7 gst ravdess seq4 sample8 gst ravdess seq4 sample9

3.5 Interpolation between styles (Prior and Posterior)

Flowtron Baseline	Flowtron λ = 2	Flowtron λ = 1	Flowtron λ = 0.666	Flowtron λ = 0.1	Target Style

3.6.2 Sampling the Gaussian Mixture ( Translating dimensions )

μ (a-flat)	μ - 2σ (c)	μ - 4σ (e-flat)

μ	μ - 2σ	μ - 4σ

Extra Flowtron samples

To reverb or not to reverb
Queen's accent
Last Halloween...	This Corona year...