I remember when I first started playing DR strings being totally overwhelmed by all of the different types of sets available. Their product naming isn't particularly informative from a technical standpoint, and it left me with lots of questions. Which ones are stainless steel? Which ones are nickel? Which ones have a round core vs a hex core? Why should I care about the shape of the core?
Well, maybe a little chart would help? I know I still need to refer to something like this every now and then.
First - let's talk in some generalities. Sonically, stainless steel strings tend to be brighter than nickel strings. Nickel strings tend to be warmer and less bright. Texturally, stainless steel strings often feel more rough on the fingers. Nickel strings tend to feel a bit more smooth. And flatwound strings, usually wound with a flat ribbon rather than a round wire, are smoother still.
As for the core design? Hex core strings tend to feel a bit more stiff. A round core makes for less stiffness at the same gauge and pitch.
FAT-BEAMS are compression wound. DR says those sets are "made with a slower and high compression winding process to produce more pronounced mids, bright highs and a super-fat bottom."
Lastly, there's Quantum Nickel used as the wrap wire on the PURE-BLUES strings. DR says this "new alloy combines the smooth feel of pure nickel with the punch and brightness of stainless steel."
Here's how all of that applies to DR's various product lines:
HI-BEAMS: Stainless steel, round core
LO-RIDER: Stainless steel, hex core
FAT-BEAMS: Stainless Steel, round core, compression wound
SUNBEAMS: Nickel, round core
NICKEL-LO-RIDER: Nickel, hex core
PURE-BLUES: Quantum Nickel, round core
DDT (Drop Down Tuning): Stainless steel, hex core, coated for longer life
DRAGON SKIN: Stainless Steel, round core, coated for longer life
LONG NECKS: Tapered stainless steel, hex core
BOOTZILLAS: Special stainless steel, hex core, coated
BLACK BEAUTIES: Stainless steel, round core, coated
RED DEVILS: Silver plated nickel, round core, coated
NEON: Silver plated nickel, round core, coated
RARE: Phosphor Bronze (intended for acoustic basses), round core
LEGEND: Polished stainless steel (flatwound), round core