I've tried different helmets & find the ones I bought in Aldi to be as good as any & better than some for noise. I wear the orange foam plugs when I can get them in, but find the best effect comes from wearing a thin neck tube up over my head & from the neck over my chin, but not my mouth. That has the advantage of keeping my loppy lugs in place & stops the ear plugs dropping out.
Interestingly, I have also found that the helmets with the best/most vents are quietest.