Yes, the BMA can be used alone.
Check the wiring diagram:
http://www.servonaut.de/shop/product...naut-bma.html&
You can see that the connection between BMA and ESC is for communicating the sound (blue plug).
I assume you don't speak German, but here's the manual:
http://www.servonaut.de/shop/media/p...1295627987.pdf