Talk:Cross-Synthesis/@comment-53539-20181208211332

One last thing to note about the change of vocal range is that when two vocals that have no overlap at all are XSY, the middle unsupported range becomes unpredictable. Though rare to create as most Vocaloids in each XSY group have at least a few keys overlapping each other, Vocaloid none the less is completely improvising the results in those rare occasions it occurs. The larger the gap between two vocal ranges in the middle, the more unpredictable this range is. The centre of this unstable vocal range can become a serious weak point producing LQ results in large gaps. Further more, it can have extreme results on the two ranges covered by either voicebanks since the calculations between the two are greatly exaggerated. In such rare cases this does occur, it is recommended that users be more subtle with how much the secondary vocal influences the primary vocal to limit the issue. '''This has been witnessed especially in unintentional XSY pairing, such as those produced as a result of illegal XSY modding. 

I don't remember where the example is, and if I did we can't link to it anyway. But I'm just noting, I can't remember the female Vocaloid in the pairing, but the original pairing was Big Al. Since Al's a V2 there was bound to be issues, but this issue stood out the most. Whenever a note of the two Vocaloids was in between their potential range, there was very ugly results and Vocaloid didn't seem to know what to do with the XSY pairing.

Its not the only example, but for the curious thats the root of this comment. It would be nice for comment section reference to find the female x Big Al song that demonstrates this in play though.