Just posted this to see if anyone has tried the Rx series roundwounds from Labella and had any dead strings. I've been through many different companies and this is the first time I've encountered a string with this much of an issue. This particular d string sounds like the core is twisted and loose somewhere in there. It actually rattles when I pluck it. I tried to rule out everything on my end from the tuner post to the possibility of twisting the core during winding. I still couldn't make it any better. What's strange too is that as I was bringing this string to pitch it didn't feel very stable and I could just tell it was a problem string. It's sad because the rest sound really nice and I can tell it's not a second rate string build by any means. Labella has been around a very long time and I wasn't expecting them to be the string that was defective my first time trying them. Just wanted to see other people's experiences and ask how the customer service experience was. I've emailed them and told them about my defective string and gave them a courteous message and hopefully they don't mind sending me a fresh set or something else to give me a good impression of their operation.