The bass response on in helmet speakers is never going to be great, the drivers cannot reproduce a bass tone due to the size of the driver, the wind noise you hear on a bike is a bass tone so it has a tendency to overpower the bass response from your headsets. I have ordered the koss equalizer that someone else mentioned and am going to try it in conjunction with a set of custom ear mold speakers. Will let you know how that works.
I am a Autocom, mixit, amplirider, dealer, build a lot of custom systems, one really important thing is the location of the speakers in relation to the center of your ear. I recently discovered just how much this location can vary person to person. I have completely changed the way I position speakers in a helmet. It gets a little complicated, but to simplyfy it, take the speakers out of your helmet, remove the cheek pads, now put the helmet on, locate the center of one ear at a time, use a finger to mark the spot(on the inside), remove the helmet and mark on the inside of the helmet where the center of your ear is with a magic marker, do it on the other side the same way. Then I remove plastic and styrofoam from the helmet to a max depth, i.e. where the speakers are even with the inside of the helmet and do not intrude on your ear. Then using foam speaker spacers space the speakers back out to where they touch the ear but do not hurt. Now you should have increased volume from the speakers, and improved response over the entire frequency range. If your music source sounds bad, lower the initial volume level of the source and add a good amp for increased performance. (in effect you are looking at the roady or mp3 player as a pre amp, and the added amp as the real power from a clean source) (adding a equalizer to a clean source may help somewhat) hope this helps you. Kieth in Tulsa
Oh call me to find out how you remove the material in the helmet.........918-446-2245
I picked up a boosteroo today at radioshack. It does sound better when sitting still. When moving it is a little better (fuller sound) than without. I think this will work for me for now.
If I use my calsci shield it is pretty quiet, the stock and yamaha tall have some noise but I can still here the music, it just has helmet noise mixed in with it.