By: Rabbi Ari Enkin
…continued from here: https://www.torahmusings.com/2012/01/baruch-shem-kvod-malchuto-i/
The phrase “baruch shem…” has other uses and appears in other places, as well. The most famous of these appearances is in the twice daily recitation of kriat shema. The practice of saying “baruch shem…” after the “shema yisrael…” originates with Yaakov Avinu who gathered his children together just before he died with the intention of revealing to them when Mashiach would come. At that moment all his children recited “shema yisrael Hashem Elokeinu Hashem Echad” so that their father should feel secure knowing that they all believed in and worshipped only Hashem. In response, Yaakov said “baruch shem kevod malchuto l’olam v’aed.”
One will readily notice that “baruch shem…” is not found anywhere in the Torah, and certainly not among the passages of the shema. Accordingly, since Moshe did not institute the saying of “baruch shem…” when reciting shema, we recite it silently (though the words must be audible to one’s ear) out of respect for him. There is another view which teaches that Moshe heard the angels praising God with the formula “baruch shem…”, and that he “stole” the idea from them. According to this approach, since this phrase is not truly “ours”, having been plagiarized from the angels, we recite it silently. On Yom Kippur, however, when everyone is elevated to the status of angels we recite the “baruch shem…” out loud just like them.
There is also a famous dispute as to whether one or two blessings are to be recited when putting on tefillin. The Ashkenazi custom is to recite two blessings, one for the tefillin of the arm, and one for the tefillin of the head. Nevertheless, in deference to the authorities who hold that the second blessing upon the head tefillin is actually unjustified, one recites “baruch shem…” after fastening the head tefillin in place. It is interesting to note that in the event that one realizes that one has said numerous blessings in vain, one recitation of “baruch shem….” will suffice to rectify them all.
We also find the phrase “baruch shem…” associated with the Kohen Gadol. When the Kohen Gadol was heard uttering God’s name on Yom Kippur, the nation responded with “baruch shem…” We recall this awesome event several times in the Yom Kippur mussaf. This is based on a passage in the Torah which tells us that when we hear someone praising God, we ourselves are to join in.Today, we accomplish this by responding “amen” to the prayers or blessings of another. In the Beit Hamikdash one responded with “baruch shem…” when hearing a blessing recited, and not “amen” as is the practice today. (…makes for a very lengthy chazarat hashatz!)
With the exception of Yom Kippur as mentioned, some authorities are of the opinion that “baruch shem…” is a phrase that should always be recited silently no matter what the context or purpose may be. On the other hand, there are those who say that one who is praying alone need not be particular to recite “baruch shem…” silently and that it may be recited in one’s normal audible manner, including as part of kriat shema, should one desire to do so.
 Pesachim 56a.
 Kaf Hachaim 61:47
 O.C. 61:13
 O.C. 619:2, Mishna Berura 619:8
 Rema O.C. 25:5, Mishna Berura O.C. 25:21
 Halichot Shlomo;Tefilla 4 note 24
 Yoma 66a
 Devarim 32:3
 Tosefta, Berachot 6:28.
 Tur O.C. 619
 Teshuvot V’hanhagot 2:46. For those who might be interested, R’ Ari Kinsberg was kind enough to send me a discussion thread on whether “baruch shem…” should be recited in a trop. Included in the first link is an image of a siddur that include trop notes for the “baruch shem…”. http://groups.google.com/group/leining/browse_thread/thread/217b5ad8709f976a, http://groups.google.com/group/leining/browse_thread/thread/217b5ad8709f976a, http://groups.google.com/group/leining/browse_thread/thread/0580eec7742c200d,