As did many of us, I waited a long time for the 20S to actually appear as a real product. The wait was worth it. This is my first Bluetooth motorcycle headset, having been a long time user of Autocom and its associated accessories. The wife and I simply wanted something a bit easier to work with without all the wires attaching stuff to the helmet. Another consideration, the helmet harness on my helmet needed replacing having developed a broken wire in the cable someplace that I could not locate.
The Sena 20S comes complete with three microphone setups. As delivered it is set up for use with an open face helmet boom mic. The other two options are a wired microphone element for use with full face helmets, and another boom mic set for use with a modular helmet. It has a paddle on the opposite end of the boom from the microphone, and is designed to stuff into the helmet between the shell and the crush layer and held secure with a piece of velcro material. This is the setup I used for mounting in the Schuberth C3 and my wifes C3W. The mounting of the clip-on is a universal clamp setup and the instructions clearly indicate it might be necessary to use the stick-on mounting setup on some helmets.
For those unfamiliar with the C3, it has a neck skirt which contains a stiff ring inside the material that snaps into a C-shaped channel on the helmet shell, and makes for a thick area that the clamp cannot get around easily. After thinking about it, I took a craft knife (scalpel) and cut the stitching holding the foam padding neck ring to its mounting point on the ring itself. That stitching area is a plastic thing that is about a 1/4 inch wide which I trimmed off about two inches of to allow the clamp of the 20S to slide into position properly and allow me to tighten the clamp screws. The rest of the installation consisted of changing the microphone from the installed open face boom microphone to the modular helmet microphone, snaking the wiring for the speakers and the microphone boom to the clamp housing. The electronics package snaps into the clamp mounting with a definite snap by pressing both ends together with your fingers. Failure to snap in properly will cause loss of audio to the speakers.
This is the clamp and shows the microphone lead (going left) and the speaker leads (going right) out of the clamp unit. The bright button on the left of the clamp unit is the latch release button to release the electronics package:
The 20S has a nice feature that I was specifically waiting on, that being the plug for use with custom earplug speakers. Plugging in defeats the speakers automatically, and unplugging reconnects the speakers as primary output.
The charging port on the electronics package is now on the lower part of the housing and is weather sealed by a rubber plug. Earlier models had this plug on top and could catch rain water into the electronics causing problems. This should not happen with the 20S design.
This is the electronics module attached to the helmet clamp.
You can see the charging port as a small black protrusion (5 o'clock position) below the telephone answer button (3 o'clock position).
This photo shows the mounting position for the modular helmet microphone boom. At the bottom right of the helmet, you can see the earphone jack cover (earphone symbol) on the black plug.
One issue with the earplug jack: The audio is very hot and distorts due to overloading of the earplug speakers even with the 20S volume fully low. I solved that issue by purchasing a small in-line volume control from Radio Shack that totally eliminates the problem. Set the volume properly low with that control, and you can still use the 20S volume control knob properly.
Connectivity is easy with my BMW R1200RT sound system and iPhone 4S. Transmit audio is so good, even with my face shield and chin bar up, that a number of people are not even aware I am riding the bike. With the shield down and closed, my wife cannot tell if I am moving or not. Receive audio is a bit bandwidth limited and the BMW audio lacks bass and sounds a bit tinny but is acceptable unless you are a total audiophile at which point, my Autocom wired system has much better music quality.
The system has voice command capability that is fun to play with. There is a 3-number speed dial memory, but since I have my iPhone paired, I simply use Siri to dial my phone numbers. Really nice.
20S ready for use with antenna extended. I have not noticed much difference with the antenna up compared to folded down.
I have not tried the group pairing feature, but it should be easy to set up with the iPhone app that Sena has available for free in the app store, and looks at your headsets through the bluetooth interface. It even tells you if a firmware update is available.
Excellent product to date, and i can recommend it highly.