With bass guitar strings, there is no question that roundwound is always the most-available. No matter where you shop for strings, roundwound will always be there and always outnumber any other string type you could buy…
…but that’s not to say you couldn’t experiment with a different type of string such as flatwound or halfround.
But should you?
Roundwound has a metal wrapping around the string which is ordinarily either nickel or stainless steel. When you drag your finger across the string, you can absolutely feel the grooves (as in physically and not in relation to sound/tone).
If you use a roundwound string with a stainless steel wrap, it sounds the most metal-like. No, I’m not referring to heavy metal music. Rather, I’m referring to the clangy/clanky sound, which for all intents and purposes is considered to be “modern bass tone”. In other words, a roundwound with a stainless steel wrap is usually “the brightest-sounding string”.
A roundwound string with a nickel wrap does physically feel softer to the touch. While not as “bright” as stainless steel, an advantage is that it won’t wreck your fingers as much.
The first thing you’ll notice about flatwound is that they are very smooth to the touch; the reason for that is because there are no upward grooves in the way the string is made.
Before continuing, here are three string types, which are from left-to-right: Roundwound, flatwound, halfround:
You can really see the grooves stick out with roundwound; with flatwound you can see that it literally is flattened for that super-smooth feel, and the halfround is “middle ground” between roundwound and flatwound.
Flatwound strings by their very nature have a “darker”, “deader” sound to them. But at the same time they have a lot more of what most bass players call “thump”, which is a reference to the attack the flatwound has, tone-wise.
Generally speaking, when you’re looking for “vintage tone”, you go with flatwound.
And when you want something that has a happy medium of sorts between vintage and modern, halfround usually serves well there – although it should be pointed out that sometimes all it takes to get both vintage tone and feel is to use a nickel-wrapped roundwound string and then roll down the tone setting on your bass guitar. You will have to experiment to see which works best for you.
What are the advantages of flatwound other than vintage tone?
First, the feel of the string is silky smooth. You can play flatwounds for hours and hours on end and your fingers will never complain (until you literally start getting tired from playing so long!)
Second, if you were looking to 100% eliminate string drag noise when moving your fingers from fret to fret, look no further than flatwound.
Third, the string is (and there’s really not other way to say this), “more forgiving”, and this is a bit tough to explain. With roundwound, sometimes unexpected noise happens, depending on what you’re playing. You’ll here a shrrrik noise here, an unexpected pop there and sometimes even hear your fingernails “clicking” on the strings because roundwound is just that bright. With flatwounds, you can get away with things that roundwound otherwise wouldn’t allow for.
It also should be noted that for you fretless players around there that are encountering way too much string drag noise, flatwound will definitely help you there.
Are there other types besides round, flat and half?
Yes, and they are:
You usually don’t have much choice with these as few companies actually make them. The character of a tapewound is that if you thought flatwound was “dark”, the tapewound is even “darker”; they usually work best on acoustic bass guitars. However some players (particularly jazz players) like the “plasticy” feel and tone of tapewound on their basses as well, whether solid-body, semi-hollow or hollow-body.
NOT the same as tapewound, but has a similar-sounding name. What this means is that the string gets smaller as you get closer to the bridge (meaning not just on the tuning machine side), where some or all of the core rests over the bridge saddle at the end. This string type is a night-and-day difference compared to tapewound.
Put another way: Taperwound is basically the bass guitar version of a piano string, and the character of a tone for taperwound is usually “brighter than flatwound but slightly darker than halfround”. As for how they feel, it’s similar to roundwound.