Just to add fuel to the fire.. Pretty much every review I've read about Arai helmets, and I will confirm based on my personal experience having owned several different models of Arai helmets over the years, is that they are LOUD. Venting is great and everything else about the helmet is top notch though... Hoping they have improved that aspect over the past few years because I'll be looking for a new helmet myself soon..
I hate to say it, but my Arai defiant IS loud. Of course, this is my first helmet, so I don't have anything to compare it to, but, it is loud. But, it also fits my head really well.