That's correct! The SoundBomb Mini needs 5A to function which the 1250GSA can output! The SoundBomb Harness is required on any application that cannot output this power.
that position is the worst place for the horn....i installed there double nut and serrated wasger with red lock tight ....horn fell off 2 times lost first found second ...i moved to the split horn ...so much better mounting
Just a heads up, the mount I used in this video has been discontinued and is no longer available. Moving forward, most (if not all) of the LC 1200/1250 GS and GSA's are going to use HMT.07.11001 for the Split Horn instead. This adds compatibility even for low-suspension models. denalielectronics.com/products/horn-mount-bmw-r1250-gs-gs-adventure-20-22?_pos=1&_sid=401875b8b&_ss=r
There's a new mount out now that's only compatible with the SoundBomb Split. You'll want that one instead. Denali has a bike finder, just put in your YMM and you'll see it.
Honestly - not sure. It's been discontinued and is no longer available from DENALI. I'll pin a comment with details, but the successor mount is only compatible with the Split version of the SoundBomb in favor of increased compatibility for low-suspension models.