The shoei gt air had loads of space, enough to place mic and not know it is there. New shape Arai's are all really close now. I do have a huge heed (XL), but still should make the chin bars a bit further out. GT Air is very comfy and quiet, internal visor is great but the visor is too open on the first click, and noisy if you open the chin vent. Not worked a solution out yet.
I've got an HJC RPHA helmet which is as noisy as a noisy thing being loudly noisy. First helmet I've ever had where earplugs are obligatory. Have thought about trying a Windjammer11 (I think it is called) skirt which is fixed around the bottom edge of the helmet to try to alleviate the problem. Some say they work, some don't, but it may be worth a punt for the sake of less than £15. I'll probably treat myself next spring.
Shoei has a tight fitting under chin piece, and is whisper quiet when the visor is down. But because such a good fit, it dies get warm in there, plus my lovely cuddly beard for extra insulation. To alleviate this, you can open chin vent, but that makes a hell of a racket or open visor, but the first click is open about 1" which is a hell of a gap! Need to work out how to jam it open 1/4 " just to allow some fresh air in. I always rode with my Arai open similar gap, just not possible on the gt air. Other than that, great helmet.
Like MrO I also bought the new Shoei GT Air. Very quiet helment, no problems fitting my Scala G9 with lots of room for the microphone boom. Well please with the helmet. Wessa