I was watching some Charlie Hunter clips;I've seen 6+ 12 strings,but 7+8?
What's the advantage(?).
The 8 string looks like a whittleded down 2x4;sounds great! But what size hands do you need?
The "advantage" is that you get an extended range. Most 7-strings are tuned to low B (like a 5 string bass, but an octave higher) although some people drop it down to A or even lower. Seven string guitars are nothing new as they have been used in jazz for years. But with the advent of nu-metal, 7-string guitars gained a reputation of being instruments of mass destruction. Steve Vai was one of the earliest rock players to use a 7-string with a low B. Before that, Alex Gregory claims to be the inventor of the 7-string solid body electric guitar. But while most players today opt for the low B, Mr. Gregory intended for his guitars to feature a high A adding to the instruments upper range. The first company to produce these guitars was Fender with the Alex Gregory Stratocaster. It never got beyond the prototype stage, though (is appears that Mr. Gregory is an exceeding difficult person to work with). After the Fender deal collapsed, Hammer agreed to pick up the model, but it too only made it to the prototype stage. One issue that likely doomed this design was the very thin gauged string required for the high A. The 8-string guitar that Charlie Hunter plays is more of a hybrid guitar-bass. The lowest three strings are tuned E-A-D as on a bass guitar, while the higher five strings are tuned A-D-G-B-E like a guitar without the low E. If you got skills like Hunter, you can make your guitar sound almost like a Hammond organ (he uses two separate amps and some signal processing too). Then there is another 8-string design (I believe it's the John Pettrucci signature model by Ibanez?) that is simply an extended range guitar. I think it goes all the way down to a low F# (below low B!). And then you have the baritone guitar and piccolo bass where you have the guitar tuned down an octave the bass tuned up an octave higher.
