I use a J&M with a long boom mike. Doesn't get in the way and works very well. I you're using J&M give them a call. They are very helpful. The last time I contacted them they knew all the items I had purchased over the last few years. Must have brought my file up on the computer. In any case I was very pleased by the personal service!
I find it difficult to ride with the chin bar up. Feels like the helmet is trying to fall backward, like top heavy. Since that feeling, I have always ridden with the bar down, except when I forget and just first drive away. Doesn't take too long to realize, someting isn't quite comfortable. Yes, you can ride with it up, but I don't know how long or far.
Also use the J&M, mic is on the boom connected to the side of the helmet, independent of the chin bar.
Ken, I use the mic that is mounted to the chin bar (EdSets). Works for me.
You can ride with the chin bar up, just make sure the faceshield is closed before you put the bar up. If the shield is open it will put a lot of torque on the neck as it scoops the wind. The mic mounted on the chin bar doesn't do you much good with it open though. :wink:
On my SyMax helmet I removed the four screws holding the plastic trim in place on the chin bar and found a piece of foam behind it with a round circle molded in it in just the right spot for the mike from EdSets http://www.edsets.com/product_details.php?category_id=61&item_id=150. Drilled a hole in the foam and used a hot glue gun to attach the mike to the foam. Drilled a bunch of small holes in the plastic trim piece in the area of the mike and ran the wires to the main part of the helmet. Works great and does not take away any space in front of your lips.
Thanks for the info folks. Ken, I do like the way you did it. I think I'll try something along those lines myself. I will be building my own headsets. The speakers are very easy, and about a month ago I found a mic element that works really good, I think it costs about $1 ($2?) - anyway, nice and cheap.
Using this mic element, it will be easier to mount to the chin bar.
 - Ken, I think that mic element from EdSet's is close to the same element that I used except I "think" his is a bit over an inch in diameter??? The one I used is only about 5/8" in diameter. I expect they work about the same.
It seems most are using the boom mics with this helmet, but due to cost and ease of construction, I'll try the mic element in the chin bar same as Ken has shown.