QUOTE (Renz @ Oct 6 2009, 03:15 AM)

What about 5-6 strings?
Playing bass is on my list, and I don't want to end up having a different bass for every strings-setup-thing.
So tell me, advantages and disadvantages
(Keep in mind I nearly know nothing about basses)
Hi Renz,
Regarding 5-and-6-string basses, I consider them to be an acquired taste, since I started out playing the classical Upright Acoustic Bass (often referred to as "double bass").
I have played several 5-string basses and generally believe the low B string to be a good idea-- but not every manufacturer executes it properly. On earlier 5-string basses, the low B tended to be rather floppy, lacking the proper tension necessary for decent punch and sustain. Most manufacturers, both instruments and strings, have since revised their designs to address this issue. While there are still a few 5-stringers with a "floppy B", they are, thankfully, becoming increasingly-rare.
The low B is a benefit in and of itself, by being able to play some of the lowest notes audible to the human ear. A 5-string has a significantly-expanded tonal range, as a result. There are a few downsides, however.
1) Many manufacturers tend to take a "one-size-fits-all" approach to making 5-string basses, which makes life difficult for us, since there are different reasons for pursuing a 5-string. Some guys like 5-string basses because they require less shifting-- you have 4 additional notes per position, after all.
Some guys just like the extended range. Pick players tend to prefer a narrow string spacing, as it allows for a faster, narrower neck, and the narrow string spacing allows for faster picking. The downside of this approach is that the string spacing is often too narrow for comfort for either slap or fingerstyle players (especially if you have meaty sausages for fingers, like I do). Narrow-spaced and Medium-spaced 5-strings have become popular with metal bassists, who often have to play very fast bass lines.
Funk players who want the extended range of a 5-string tend to prefer wider string spacings, as it allows more space between the strings for slapping and popping technique. The downside of a wider string spacing is that it results in a wider, chunkier neck, that really isn't conducive to trickier left-hand techniques, like chording, for example.
Fingerstyle bassists, like myself, tend to prefer either the wide spacing, or a medium spacing. As a result, we are seeing more companies offering both narrow and wide string spacings-- like the Ibanez SR series (narrow), or the BTB series (wide).
2) 5-string and 6-string basses can rarely match the intuitive playability of a 4-string. The bigger, chunkier neck inherent in a 5-or-6-string bass tend to be slower than a stock 4-string. Also, the 4-string allows for both a fast neck AND a more slap-and-pop-friendly string spacing. With a 5-string, it is either one or the other-- you just can't have it all. There is a reason why many of the bass-playing greats, including Victor Wooten, Bootsy Collins, Flea, and Geddy Lee stick with 4-strings.
3) As for 6-strings, I can see the advantages for fast runs and chording techniques, but 6-strings are almost always only available in a narrow string spacing-- I have seen a grand total of less than a dozen wide-spaced 6-strings. They seem to be popular with Jazz, Fusion, and Pop musicians, as they offer an excellent range. But funk, rock, and blues musicians will tend to shy away, since the advantages of a six-string don't matter as much for those styles of music, and, as a result, do not justify the sacrifice in playability.
So, there you have it-- in a nutshell, the more strings, the more specialized the instrument becomes. You have to take into account what styles of music you play, and what are your primary left, and right-hand techniques. As a result, it is actually quite common for professional bassists to have 4-and-5-string basses, 5-and-6-string basses, or all 3 in their collections, depending on their needs.