the spectrum has nothing to do with it. If your temps are high, I don't care what Kelvin temp your running, buds will be less dense. The same things happens to greenhouse grown buds.
I run mostly 3500K lights and have had the hardest, and tastiest buds ever. Check around, the majority of COB and other form factors of white LED run 3500k. There's a reason for that. Results from hundreds of grows have proven 3500k to be the best all around spectrum to use.