And as Vai told me in an interview for Australia's Mixdown magazine last week, he feels a sense of gratitude in seeing where players have taken it. "When it first came out, I was the only one playing one aside from Uli Jon Roth," Vai said. "They weren't available commercially. And once it became available I think there were some people that gravitated towards it because they were fans, and some people gravitated towards it because they saw the potential in it for something new. And they sure did do it. When the Passion and Warfare and the Whitesnake albums came out, which I used the seven-string on, there was a surge in sales."

Vai said that the market for the instrument then subsided, but he knew that the youth that were listening to his early low-B excursions hadn't yet matured, "and I knew that once they did and once they started making music on it, there was potential there for a whole different sound. I didn't realize it was going to be as powerful as it turned out to be!"