These strings have been made for decades; they have a nylon core, which is flatwound with nylon on the G and D strings, and with monel (a nickel alloy) on the A and E strings. The strings have a comfortable soft feel, with a lighter tension than most steel strings, and good tone and volume.
Rotosound indicates that they are good for many styles of music, including jazz, rockabilly, bluegrass, and contemporary styles. They are flexible and durable enough for comfortable slapping, but some players report that they have a sort of "boingy" (like an elastic band) sound under heavy slapping. The top strings have kind of a "tan" color to the wrapping, so they almost appear to be gut strings from a distance. They have a light feel but still have a warm tone. You might consider this set to be a alternative to gut strings if you want some of that flavor -- but with more definition and longer sustain than real gut.
You can bow them, but there are far better arco strings out there. For a similar pizz "vibe" with better bowability, consider the Pirastro Obligatos.
Also note that these strings do not have "Ball Ends" but rather loops on the tailpiece end of the strings. Looped bass strings (which are not as common as the ball ends we're used to seeing) are installed by wrapping the string around the hole in the tailpiece and back through the loop - similar to strings on a classical guitar.
Rotosound does not list gauges on their packages, but I have taken the time to gauge all the strings using a digital caliper and present the following unofficial measurements of the "Superb" set for your reference:
That's no typo, the D is the biggest string in the set; the E and A are wrapped in a nickel alloy and thereby have more mass, so they're not as thick.
Also available as a "bumped" set: A bumped set, simply, is a custom set of strings with SUPER-light tension.
It is traditionally created by substituting a string designed for a higher pitch for each string on your bass; commonly, this means using an A-string for the E, a D-string for the A, a G-string for the D, and a High C-string for the G. Thus, you're "bumping" each string down one position on your bass, but - and this is the key - you're still tuning it E-A-D-G.
When it comes to rockabilly bass playing, sometimes ease of play is paramount. Many players find that standard string sets are just way too stiff to play 3+ hours of non-stop slap bass on. Thus, a bumped set can be a happy medium between the extremes of higher-tension "real" upright bass strings, and the tonal compromise of putting weed-whacker line on your bass (no, seriously).
*About these unusual strings and their use on 3/4 sized basses
Rotosound RS4000 strings are, according to the manufacturer, designed for 4/4 sized bass. As a result, the “playable” area of the strings will usually end up at least partially wound on the machines, and it’s also fairly common for the black “afterlength” silk to overlap the top of the bridge of a 3/4 sized bass unless you make accommodations.
Here’s a quote from the manufacturer, which was sent to a customer:
Our RS4000 set is for a full size 44” scale double bass. The machine that they are made on has not changed in length since inception back in 1961. This is the standard length for all professional bassists that play with most philharmonic orchestras.
Your bass is probably a ¾” scale, (41 ½”) size that is very popular these days as they are easier to handle for regular gigging musicians.
You are correct that the black silk should not encroach on the bridge.
My thoughts on that explanation:
- In my (extensive) experience, the vast majority of players who play bass actually play a ¾ sized instrument – it has become the most commonly accepted “full size” bass, worldwide, and;
- What happens in “Philharmonic Orchestras” hardly seems relevant to the use of these strings, which are better suited (in my opinion) to more contemporary, pizzicato styles. But to each their own.
Bottom line – the strings CAN be used on a ¾ sized bass (LOTS of players do so), but I recommend that you use care to install the strings in a way that help to reduce those issues. We include a tip sheet to help you do this, it will be in the package with your packing slip.