THERE ARE TWO DISTINCT MINHAGIM WITH REGARD TO THIS MATTER.
THE BAAL HA’TORAH TEMIMAH’, IN HIS SEFER ON TEFILA CALLED BORUCH SHEAMAR SAYS THAT THE BRACHA SHOULD BE SAID ALOUD.
THE MICHAS ELUZER AND OTHERS HELD THAT IT SHOULD BE SAID QUIETLY.
WHATEVER ONE DOES – ‘YESH AL MI LISMOCH’, BUT MINHAG HAMAKOM TRUMPS EVERYTHING ELSE.