The quietest helmets on the planet are wholly inadequate to protecting your hearing while riding. Some are better than others but none are sufficient. The other thing many don't understand is that your helmet is designed to work in clean undisturbed relative wind (not behind a windscreen). Don't believe me - stand up on the pegs to get out from behind your windscreen and see how little wind noise and buffeting you get.
With that said, I'm a fan of lower profile windscreens and custom molded in-ear-monitors, specially Sensaphonics. When you go look at their web site I'll warn you ahead of time you're going to gasp at the price. I've been using my pair of Sensaphonics for over a decade and can report that they are all day comfortable (12-14 hour days), day after day on multi-week rides, and provide passive attenuation of noise in the high-30dB range. I use them mainly for intercom clarity when riding with my epic adventuring buddies and we're yakking on the channel pretty much all day.
I'm sure there are probably very good options out there that are less expensive but I've been so happy with my Sensaphonics that I just haven't looked and compared anything else. When you see headliner musicians on stage it's almost certain they're wearing Sensaphonics. Same with the high end of motorsports. You can specify that you want drop cords on them at any length you need and they are no factor at all on fitting inside a helmet.
Loosing your hearing over time is one of the worst (and preventable) things that can happen to you to diminish your quality of life. Spend as much as you can afford to prevent that.
These are the ones that I have:
Custom IEM, studio reference, full-range response via 2 balanced armatures: 1 high, 1 low. Our custom classic, the original soft silicone in-ear monitor.
www.sensaphonics.com
The price for me included the audiology appointment for testing and fitting.