I read an interview with Paul McCartney recently. He talked about his gear and mentioned he bought a 5-string Wal and used it on the recording of Free As A Bird. For one note.
FIVE-STRING TASTE
Paul now uses a Wal 5 string bass in the studio and for part of his live shows. I think it's important to take yet another page from the McCartney bass book when it comes to 5 string bass playing. There are (at least) two ways to approach the switch from 4 to 5 string bass (where the 5th string is a low B).
One way would be to take a step back and re-approach the bass with all five strings in mind, to seek it out as a whole new instrument because in effect that's what it becomes with that approach. You've no doubt heard a number of bass players who have taken this approach, and they lean quite heavily on the low B. This can be troublesome: while we bass players tend to love low rumbling sounds, there are not many others like us out there in the world. One gets the feeling that these bass players are using their newfound low B string as a weapon to grab new power in the band sound. Interestingly enough, you 'generally' find these sorts of bass players in the club scenes and maybe it makes sense there.
The second way is to think about your bass as the old 4 string instrument -- with a fifth string available on top for effect. For one thing it makes it much easier to play without thinking so much. It's so easy, while playing, to forget that the string at the top of your neck is now a B instead of an E that it's almost survival to adopt this method both live and in the studio. Approaching 5 string bass playing in this way also causes the bass player to use the B string a bit more sparingly, and hence to much better effect.
Paul McCartney on recording "Free As A Bird": "I played the Wal, and what I liked was I played very, very normal bass, really out of the way, because I didn't want to 'feature'. There are one or two moments where I break a little bit loose, but mostly I try to anchor the track. There's one lovely moment when it modulates to C, so I was able to use the low C of the 5 string and that's it, the only time I use the low one, which I like, rather than just bassing outand being low, low, low. I play normal bass, and then there's this low C and the song takes off. It actually takes off anyway because a lot of harmonies come in and stuff, but it's a real cool moment that I'm proud of. That's my Wal moment." (footnote 2)
He hits that cool low C three times actually, the first time during the first note of George's solo.
Today, every time Paul comes out with a new album, people tend to be disappointed. As with all music, opinion is completely subjective (as is much of this article).
But the one thing that's not so open to subjectivity is his bass playing. Whether on his Rickenbacker, his Wal 5 string or whatever, he remains one of the top bass players in the world. For a guy who could rest on his laurels as one of the prime innovators of rock bass playing, that is a solid testament to him as a musician.