You need some sort of hard case--a soft-sided gig bag will be a big mistake. I use a couple of different Protec cases, but have also used the factory cases with success. I have ridden bikes with and without luggage racks and back rests/sissy bars and transported horns on both successfully, but a luggage rack and back rest (can you even get a sissy bar any more) make things easier. Bungee cords work well to attach your horns but don't skimp on the quality. Your cases should be secured to prevent both front/rear and side to side movement. If you forget the side to side you will probably live to regret it. As an added safety I loop the shoulder strap of the Protec cases over the back rest--just in case. Heavy duty lawn and garden "trash" bags work well for keeping your horns dry, just tuck up the loose ends tightly. It's also easy to carry spares. I haven't had a bike without some sort of saddle bags since 1974 and that's where I carry my music and other items. One thing you have to be aware of is motorcycle vibration--your motorcycle will vibrate and things that are allowed to rest against one another without adequate padding will--repeat will--damage one another. So your iPad needs to to be in it's own padded case and other items need to be padded as well. In summation: a good luggage rack, a back rest, good bungee cords, saddle bags and heavy duty lawn and garden trash bags--you should be set. I've been transporting horns that way since 1970, and haven't lost one yet.