There is one other technical issue that needs to be considered when pairing a Bluetooth headset to a Garmin GPS, and that is what protocol is selected for the pairing.
Bluetooth headsets in general (by this I mean all Bluetooth headsets, including single-speaker over-the-ear models used for office telephone use as well as the two-speaker units designed for stereo sound in motorcycle helmets) can be paired using one of two protocols: Headset Protocol (HSP) or Advanced Audio Distribution Profile (A2DP). Headset Protocol delivers mono sound only, A2DP delivers stereo sound.
Since about 2010, all Garmin motorcycle GPS units have supported A2DP protocol. Any Bluetooth helmet speaker & microphone assembly that has two speakers (left and right) produced since about 2010 will also support A2DP. It is
probable, but not certain, that A2DP will be the 'default' protocol that has been factory-set in both the headset and the GPS for pairing. If you are getting poor-quality sound from your headset, or monaural sound from your headset when listening to music, you might need to check and confirm that both the GPS and the headset are using A2DP protocol for pairing. Details about how to do this will be contained in the owner manual for both the GPS and the headset.
Sena makes a utility program called
Sena Device Manager that can be used to update the firmware in Sena headsets and also change various settings of the Sena headset, including the choice of default pairing protocol (HSP or A2DP). You may wish to download this little app and use it to confirm that your headset is set to use A2DP for pairing.
Here are some links to further background information about this subject:
Bluetooth Headset Compatibility for zumo 590 and 595
Garmin Bluetooth A2DP (Advanced Audio Distribution Profile ), Zumo only option? (a very old post from our forum)
List of Bluetooth profiles - a very lengthy article - TMI for sure - from Wikipedia, but useful for providing specifications for HSP and A2DP.
At the link provided for the Sena Device Manager, you will also find a number of other Sena applications - unless you are an expert on the subject of Bluetooth pairing, profiles, making your headset work perfectly with your GPS, etc. I suggest you stay away from all Sena applications other than the Device Manager - otherwise, you will just dig yourself deeper into a hole.
Michael