I emailed DR regarding these strings, and the reply was as follows:
This is Steve, one of the sales reps for DR Strings.
The DDTs are based pretty much on the LoRider principle, with nickel plating on hexcore. The tension is different due to a different winding process, so the result will be much deeper and more stable in the intonation.
I hope this helps. Thanks so much!
I have a set on my SS2 5er and they actually seem to do what they claim. We tune down a whole step (yeah, the low A isn't super useful).
A lot of strings I've tried will waver above and below the desired pitch when tuning before settling in to what I'm trying to tune to, whereas these are spot on. They seem REALLY floppy when you take them out of the pack. More so than any other string I've tried, but once they are tuned up they rock.
My local shop didn't have the super heavy gauge I'd like to try, but considering the strings are .45 - .130 (I think) they are not too floppy to slap with and intonate much better a whole step down. They sound quite good too!
Without even trying them, I have to think these are a great option for 4-string players who drop tune, but especially for 4-string players who drop tune all the way to BEAD. Many brands don't market for that tuning, so you're stuck paying for 5-string sets and 'throwing away' the unused G-string. Both the DDT-55 set and the DDT-65 set would probably work:
Ok first impressions of these strings? If you're tuning down get them. I'm tuned a whole step down on my Corvette 5 and it made all the difference. The low A is still a bit floppy and decays quickly but it's much more usable now than with the normal DR .130 I had on originally. The rest of the strings feel as if I was tuned normally (E,A,D,G) again. That is the tension doesn't feel sloppy and loose. I did notice that they weren't as bright as the fresh DR's they replaced but they still had plenty of zing to slap with if needed and they have a good growl when using the bridge pickup. So far, I'm impressed.