usually pick for better quality sound but thumb can be used
Which thumb? If you don't play with a pick (finger picking or classical guitar, for instance), then you very much use your right thumb to pluck notes (generally bass notes) or strum chords (generally upstrokes; you'd use your middle finger for the downstrokes). As far as your left thumb, it is mostly unused except for finger picking, where sometimes one wraps one's thumb around to pick up bass notes on the low E string. I once jammed with a guitarist who could thumb wrap-around the bottom *two* strings, but my hand is definitely not big enough for that.
Using pick is not a matter of number of strings, it is rather a matter of personal preference or style of music you are playing. With a 4-string bass, you can use both pick and fingers.
Yes he does in the video Dance Dance he does
One thought that I have which may possibly benefit you is a blues technique called constant bass, and alternating bass. With the constant bass, you're using your fingers for the higher notes, and your thumb on your bass strings for a bass sound . With the alternating bass, you're using your fingers on the higher notes, and your thumb on the bass strings on the beat - therefore, the alternating bass term
Sometime before South of Heaven was released
Yes.
Which thumb? If you don't play with a pick (finger picking or classical guitar, for instance), then you very much use your right thumb to pluck notes (generally bass notes) or strum chords (generally upstrokes; you'd use your middle finger for the downstrokes). As far as your left thumb, it is mostly unused except for finger picking, where sometimes one wraps one's thumb around to pick up bass notes on the low E string. I once jammed with a guitarist who could thumb wrap-around the bottom *two* strings, but my hand is definitely not big enough for that.
If you are referring to how people strum the bass. It is a matter of preference and there isn't really a dominant way to play the Bass Guitar. Which ever feels more comfortable is the way you should choose. I play the Bass myself, and I prefer a pick. I also play, and I use fingers only. I place my thumb on the pickguard and use my first two fingers to pluck.
Using pick is not a matter of number of strings, it is rather a matter of personal preference or style of music you are playing. With a 4-string bass, you can use both pick and fingers.
a pick or his thumb
You can fingerpick using your....fingers or pick it using a plectrum/pick. Alternatively you can even pluck it or use a bow on something like a double bass.
You can, but it's better to use your pointer and middle fingers.
It doesn't matter, but all the bass greats play without one. I personally don't, and you'll find that there is a great split in the bass-playing community - to pick or not to pick? Most don't, though.
There are two ways it can be done, you can hold your fingers together as par a pick and connect with the front of the finger, and a bit of the thumb thereafter. Or you can gently rest your thumb of the picking hand on the string, creating a node, while fretting a note, and pluck the string with a finger. I use the second method, be sure to be very light with the thumb however.
Yes he does in the video Dance Dance he does
It can be either bass cleff or treble cleff, however, most of the euphonium players I know play bass cleff, and I think bass cleff is the standard.
One thought that I have which may possibly benefit you is a blues technique called constant bass, and alternating bass. With the constant bass, you're using your fingers for the higher notes, and your thumb on your bass strings for a bass sound . With the alternating bass, you're using your fingers on the higher notes, and your thumb on the bass strings on the beat - therefore, the alternating bass term