I spoke with Sena today and the company rep told me that there hasn't been any changes to the 20S system since it was first released in the Summer of 2014. They said no improvements in the design or components, only the firmware updates.
I'm confused because there have been people say that changes were made since the first release of the 20S!?!
ANY INFO FROM ANYONE HERE???
AFAIK, all of the 20S models came with the better speakers. The 10S is the one that had the different speakers, depending on date of manufacture.
I have or had the old SMH10's, the 10C, and the 20S. I moved the SMH10's into my dirt helmets when I upgraded to the 20S models. I tried the 10C (camera version) and did not like the software of the 10C, so I sold it. As I understand it, Sena is replacing the 10C and not working to upgrade the software. The older 10's are no longer supported, but are solid, if dated, units. The 20's are okay. I say okay, because I've had them for a little over a year and neither of my 2 units lasted a year before they started having issues. My unit was replaced quickly without drama, but my wife's unit has been sent back and it's been crickets from Sena for over a month now.
The 20's are a good unit, but do have some niggles. First off, their range is not nearly as far as advertised. If you're two up, no biggie, but if you're on separate bikes, as my wife and I are, then it can be an issue. Secondly, if you wear ear plugs, as I do, then once you get to max volume it beeps constantly with a high volume warning. It is super annoying and will continue to do it if you're even near max volume and not at max. You can not disable that feature. Also, the wonder wheel has very little friction, so with a gloved hand it's very imprecise. The boom mike works well, but the permanent mike is cheap and low quality, so even with a full-faced helmet you need to use a boom.