After extensive testing and fixing the sample that made from vocaloid (record the vowels) this is quite valuable for me
There is conclusion (for me)
- Some vocaloid vbs like to share the same frequency or hamonic when play similar note. Not because of their poor design, but because of me using it the way they are not design for.
- Vocaloid does not have complex hamonic (and range) as human voice and it was sing so precise basically digital accuracy without amplitude modulation. Because of this, it might cause deteriorate sound due to upper hamonic share similar frequency or "almost" the same frequency. While playing the multiple note with sample that record from vocaloid.
- Hollow sound. This problem occur mostly due to "Some" vocaloid like to share similar frequency, and if I play a multiple note the fundamental frequency start to remove each other because they fighting for their frequency range, and "who ever have more amplitude will always win". This is cause the phase correlation problem, and the result is metallic artifact sound.
There is conclusion for who might have the same problem when make a vocaloid sing multi-tracks or try to make a multiple chorus from vbs that share similar fundamental frequency.
- Since vocaloid does not have complex hamonic as human and it was sing too precise you can avoid this problem by simply re-arrange the note by put it slightly off the grid, maybe a few millisecond or a few samples
- Vocaloid does not have randomized or humanized algorithm, every time you export the same note same word it will sound exactly the same.
If we use vocaloid normally as they are design for, This problem are very rare to nonexistent. However there is rare occasions if you facing metallic artifact sound, because of very static upper hamonic that vocaloid generate. You can fix this metallic sound by modulate the amplitude of waveform. Simply de-tune or fine-tune the voice slightly off the key.
Note: Put the note slightly off grid or de-tune the voice is a non destructive edit. Actually this is very natural for trying to simulate human voice.
I post from my experiment. I am not intended or purposely attack the vocaloid product.
