I'm mainly an acoustic guitar player, branching out into electric guitar and (a bit) bass guitar.
I don't know much of anything about bass technique - I just have one lying around and muck about on it sometimes.
I wondered if it's the norm that you must always mute all strings but the one being played, is this a core feature of how the bass is played that you explicitly mute strings with your right hand?
Rather than asking what's correct, try it and see whether you like it. If you play a part without any muting and you like how it sounds, stick with it.
However, most bassists mute a lot, and here's why:
Not all of this is right-hand muting. Typically it's a combination of right-hand palm muting, right-hand finger muting, and left hand muting.
The renowned pop bassist Carol Kaye often used a piece of felt across the bridge, permanently muting all the strings, for a clean spare bass sound when picking.
Generally players do mute unused strings. The commonest is using RH thumb on the bottom string (unless being played!) Some will use spare fingers of RH, and/or fleshy part of LH fingers. I know a bass player - session guy, incredible player, who devised his own muting method which involves each digit muting an unused string, leaving one spare for playing the note. He usually uses a 5 string. It's really uncanny to watch, but so, so clean. Most folks will derive their own method, and probably won't actually be aware of what they're doing. Like me. It's something that just develops for a lot of us, helped by the fact that we went through it all on guitar, too. There's obviously going to be a variation for those who use a pick. You don't.....do you?
I play bass myself, started off with guitar of course, and I must say that both instruments are very different when it comes to muting. While a guitar, depending on the genre or the part you're playing (like harmonic parts and ringing notes), can sound quite good without muting... A bass often does not.
The reason for that is that the bass forms the backbone of a song, together with the drums. A song with a muddy or imprecise foundation sounds not as good as a tight bass-tone locked in with the drums (so played when it needs to be played and muted when it does not). If you compare the playing style of a guitarist and a bassist, the bassist often uses one tone at the time. The guitar player uses more harmonic chords or powerchords, so hearing more than just what's being played doesn't matter that much.
It also is very important to mute your bass correctly because of the string gauge. Bass strings are much thicker than guitar strings. So physically, the vibrations when playing a string are much stronger, so the strings next to the one being played are moving too. Therefore it is, especially for a down-tuned bass, crucial to mute your strings correctly. Even if you just play one string, the others will be moved by the sound vibes as well and are usually out of tune, compared to the tone you're playing.
However, don't be too obsessed with muting. As long as you keep your playing style clean and mute consciously whenever there's a risk of you smashing more than one string, you shouldn't have any problems with the tone. Keep an eye on it, practice a bit and you'll be fine.
Because of the bass’s fundamental roles in harmony and rhythm, it’s especially important to play cleanly, clearly, and deliberately. Among other things, that means muting any unwanted tones. Bassists have a variety of muting techniques, using either hand or both together.
On the fretting hand, you can touch unused strings with your fingertips, or lay fingers across the strings, or lightly slap the strings between notes for a percussive choking effect. On the plucking hand, it’s very common to anchor the thumb on the E or A string, muting lower notes, and it’s not unusual to also mute strings with the plucking fingers. It’s less common to mute higher strings with your non-plucking fingers, although some prominent players like Jaco Pastorius use that technique. With a pick, you can anchor fingers on the higher strings or touch the strings with the side of your hand.
You won’t always need to deliberately mute all of the strings, but because of the importance of clean play, you’ll find that most bassists are aggressive about muting.
