I know that a six string bass costs more than a 4 string. I wonder though, in the case of 2 basses like the BTB400 and the BTB406 both from Ibanez. My question is, If I bought the 406, would I be getting a better quality bass that had a better sound quality than the 400, or would I just be paying 160$ more for two extra strings. In other words, is the 406 the same thing as the 400 with 2 extra strings?

The first question is, how much playing have you done? If you`re looking to jump in, go with a 4 string, and progress up as you get comfortable (I`ve been playing 4 for 2 years, and am looking to start messing around with a 5 string).

In theory, tone should be similar for both your 4 and 6 string. The wider neck on the 6 string will affect tone a little.

To be honest, I think you are just paying for a wider fingerboard and extra strings. In my opinion, I`d say go with the six string, but try both first. Get the quality over the quantity. The six string just lets you play more notes. I say go with that one, but if you`re just beginning, and it already sounds like you`re not, go with the four stringed. Hope this helps. Bye!