两种预置声码器各有优缺点，该在什么方向上改进？

预置的两种声码器g_hifigan和pretained，
用g_hifigan的生成出来的音频，音色特别准，但是会带有电音
用pretained的生成出来的音频，音色没那么准，音量也会变小，但是就不会带电音

这种问题应该往哪个方向去改进？使得结果两种优点都具有

是声码器训练问题?还是源音频的问题？还是合成器？

Compare the audio produced by the two preset vocoders, g_hifigan and pretained, and review the issue's possible sources: vocoder training, source audio, or the synthesizer. Done means identifying the cause of the electronic artifacts, reduced timbre accuracy, and lower volume, then defining a direction that preserves the stated advantages of both outputs.

Written by the indexing model from the issue text.