To answer questions about sound quality - I have owned the Scala Q2's (dual set) for about 2 years and then I purchased the Sena's (dual set) about 1 year ago. The Sena set had way more bass and volume than the Scala's ever had, (plus the big button/dial on the Sena is so much more easy to control) Anyway, I took the old Scala's out of our full-face helmets and mounted them to our open-faced helmets, replacing them with the Sena set. Because its been summer and hot in south Texas, recently we have been using the open faced Scala helmets - it sounds as if I am listening to old AM radio- thin, tinny, and poor compared to the Sena. The Sena speakers are larger and a tad thicker but much better quality. I use my phone, bluetooth connected, for Mp3's and also streaming Pandora and Jango radio. If you are used to the earbuds that just hang in your ears, the Sena's will sound much better, BUT, if you are using the ear buds that you insert deep in your ear canal, there is no helmet-mounted speakers that will equal that kind of bass.