Using the app you should be able to turn the input sounds off completely. It works on my boom 2.
No app support for Wonderboom (annoyed)
You can turn it off in app (on the boom2 but I assume for the wonder boom also)
Matter of choice to some extent. I'd still go for a boom2 for the ability to use 3.5mm in for a start. But the 3 does have other stuff going for it.
I've got the Wonderboom but sending it back because the power up and power down noise is just way too loud and I use it at night. Anyone comment on this one?