Yes it exists: https://ccrma.stanford.edu/~juhan/super_spec.html https://ccrma.stanford.edu/~juhan/super_spec.html But the issue is not that the spectrogram is

Yes it exists: https://ccrma.stanford.edu/~juhan/super_spec.html https://ccrma.stanford.edu/~juhan/super_spec.html But the issue is not that the spectrogram is low quality. The issue is that the spectrogram only contains the amplitude information. You also need phase information for generating audio from the spectogram