Interesting question…..The band I was in at the time I switched to a 5 was in a “drop” mode a lot and I preferred to stay in standard tuning so I needed the B string to get the lower D without sounding like a girl in a tutu on the high D. That was my sole reason at the time but now it’s been about ten years or so and I realize there are many more reasons for me to stay on a 5 or even a 6 string bass. Efficiency of movements is a big reason now. In one hand position I have more notes to use and octaves without moving all over the neck. The necks of 5 string basses seem to be so much more stable and require less tweaking of the truss rod and bridge to keep good action and intonation. Many of my 5 string basses are 35” so they have a tension I prefer now and they seem to sound deeper and growlier. I like tighter string spacing for fast runs up and down scales. Bigger body covers more of my gut. B string makes a great thumb rest for regular bass lines and the low D or C on the B string sounds so huge on a good bass and proper amplification. Sometimes when I hit the open B string on my Warwicks and look down at my pedal board to watch the tuner my eyes are vibrating and it’s hard to focus clearly and I can set car alarms off. Try that with a 4 string…The whole vibrating eyeball thing and car alarm thing are pretty stupid but fun. The list before that are the real reasons.
