For those cheap ba****d like me , try this. Go buy one or two musical greeting cards the one that play the real songs.
Remove the speakers from the cards & attached to an old ear phone wire & jack, slide into the liner of your helmet & route the wires so that they drop out the back.
These speaker are not bad, considering, and they are flat enough to stay behind the liner & not felt.
I may upgrade to a plug-in port in the helmet if I'm feeling adventurous one day.
This may work for some & not others; but hey!,think how much money your going to waste trying.
I hook mine up to my Ipod play my Madness albums & ride.