Researching first IEMs and see differing noise attenuation specs. For example Shure 535 has 37dB and I see many others in the 20s, including higher end ones. A new Mackie series says theirs is up to 40dB. I've tried the Shure once and the isolation seemed good for me. After loud concerts and dumb headphone use as a teenager, I think more reduction is better for me. Those who play in louder situations do you find IEMs in the 20s range fine? Fill me in if I'm missing anything about this, interesting to learn! Thanks!