I currently ride with a half helmet with an SMH10 mounted on it and I use custom moulded ear buds with the SMH10. My helmet came with filler ear covers, similar to the ones for the Cavalry helmet. Originally when I installed the SMH10, I mounted speakers in the filler pads but I found that the wind noise was so loud I couldn't really enjoy music while riding. I had to turn the volume to max and then if I stopped moving, the volume would be too loud. I also found the pads were too hot and confining - not really the half helmet experience I enjoy.
Moulded ear buds were the answer. I hadn't realized how loud the wind noise was that I had gotten used to - I now know how damaging that noise can be to a Riders' hearing. I can actually enjoy music at a reasonable volume now. Conversations with fellow riders and GPS instructions are much clearer and private. It doesn't matter whether I'm moving or stopped, in traffic or not, the volume setting remains the same.
My helmet is due for replacement and even though my SMH10 is working fine, the Cavalry communicator has additional features that would be nice to have. If I could use my moulded ear buds with it, I'd be sold but I won't give them up. If SENA ever decides to add an earphone jack to the Cavalry helmet, please put my name at the top of the announcement email list.