I've tried D'Addario XL, Rotos 66's, Deam markley Signature and Helix HD NPS, Warwick Red Labels, Elixir nanowebs... and the best strings for growly JB sound are DR Lo-Riders which I use for last two years (in gauge 100-40 for standard tuing). Can you tell your experience in fiding most agressive strings for Jazz Bass? I wanna try TI Jazz Rounds... are they worth money?
I have TIs Jazz Rounds & I can tell you if you are looking for an aggressive "growly" string, don't go near TIs.
TIs are made differently, w/a long buffer layer of silk between the core & outer wrapping, like a concert string. (The lower strings do take on certain pizzicato upright bass qualities.) For the most part, though, they are a light sounding string & sound terrible with single coil pups--lean, very lean. To make these strings shine, you should use double coils, neck pickup only.
I use a 6 string set on my Ibanez SR406. Even just using the neck DX6 (split coil in a soap bar) pickup the G & C strings are too twangy unless I give them a HUGE boost at 250hz & 500hz. Furthermore, my stock Ibanez onboard active preamp (not by passable) is one of the dullest ever designed, & again it's too my advantage that it smooths out what ever inherent edginess in those two strings.
The twanginess of those two strings a result of the extra tension. These are not balanced strings. The low B has less than 27 pounds of tension & it (along with the e) sounds on the dead side. The G has 34 pounds of tension, & it (along with the C) has nice, fast, snappy transients.
I was about to give up on the TIs, bit my band mates like them. So do musician friends of mine, & now they are growing on me.
I use their light sound to my advantage. Most of the repertoire our trio does is folk & jazz, with the guitarist playing a small bodied Tacoma guitar. As stated earlier, the low deader sounding strings take on a deep (but not too large or punchy) pizzicato bass quality. When I solo using the upper strings in the upper register (with treble & reverb help from my pedal) the bass takes on a jazz guitar quality.
My concept of ultra growly is the Marcus Miller sound. My other basses have DR Hibeams, & to me they have always represented the epitome of growl. (At least slap growl, I guess there are other types such as Rex Brown's.)
Recently I purchased a Fender Marcus Miller Jazz bass. The hex core strings that came with it were excellent, but I purchased a new set of DR MM Signature Fatbeams anticipating that the Fatbeams would be the real deal. On that bass the Fatbeams were lean & unconvincing. The E & A at 105 & 80 were particularly hollow & metallic.
What came with the bass looks exactly like Fat and/or Hi Beams, they got the bright Marcus Miller slap sound, only with body, & they are hex cored. I am increasingly convinced that these have to be Low Riders, what else can they be? Just like Hibeams only hex cored.
I have to say I've been wrong headed about seeking low gauge round core strings with the assumption that they would facilitate faster technique. The stiffer strings give more bounce that promote faster finger plucking of the right hand, & faster fingering on the left.
Once I confirm that I have Low Riders on my Marcus Miller bass, I am going to buy a set for my 30" SX fretless. I have Hibeams on & I can't even feel them the Tension's so damn low!
I can't tell you about Roto 66s. I don't have the money to experiment. If you like your Low Riders (& I can see why) but want more growl at the expense of deeper lows & mids & a percussive attack you can try Hibeams.
