The prototype of the eVY1 chip was seen in the "YAMAHA VOCALOID LSI "NSX-1" based Singing Keyboard" demo and more demos were also shown afterwards. This device used the voice of VY1 and initially this was the voice that was going to be inside the Pocket Miku device. After some negotiations, Hatsune Miku became the voice and was built using VY1's base as the developers argued that only Miku's voice would do.
One known product that uses this is the VOCALOOP.
|YAMAHA VOCALOID LSI "NSX-1" based Singing Keyboard||YouTube|
|Product Information (Hardware)|