Q. Can a Baal Tokea blow the Shofar for training on Erev Rosh Hashana?
A. Shulchan Aruch (O.H. 581: 3) rules that one should not blow Shofar on Erev Rosh Hashana.
Whether, one may blow for teaching or training, seems to depend on the reason involved.
Mishna Berura (24) quotes Minhagim that a reason is not to let the Sotton become used and accustomed to the blowing, thus not being afraid of the Shofar and not fleeing.
Therefore Mateh Ephraim (7) quotes Maharil and others who rule that even for practising one should not blow the Shofar during Erev Rosh Hashana.
Mishna Berura mentions that another reason is to separate between the Tekios that we are obliged and the ones that are only a Minhag, as in the month of Elul, so one may blow in the privacy of his home.
Eliahu Rabba (4) mentions that one may for training blow inside a Mikva or other secluded room.
Kovetz Halochos also permits when it is done in a private room and the voice of the Shofar can not be heard publicly.
Horav Shlomo Miller’s Shlit’a opinion is similar.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a.