[Avodah] Borchu UVoruch Shemo between Borchu and Shmono Esreh

[Micha Berger]

AISI, the question of whether BHUS or "Or olam" (or other piyutim), or
even singing during Keil Adon would be a hefseq first depends on
defining hefseq. I can think of three definitions:

1- Something which causes hesekh hada'as
2- Something which breaks the matbei'ah tefillah
3- Something causes a pause where none is allowed -- eg a birkhas
hamitzvah which would no longer be oveir la'asiyasah

I don't see how singing could cause #1 oe #2, and I can't think of a
case where we sing between a berakahah and the mitzvah/hana'ah.

BHUS isn't hesekh hada'as, nor are some of the Sepharadi reponses (eg
responding to chazaras hashatz "Atah qadosh" "Emet!" "veShimkha
qadosh" "Emet!" "uqedoshim..." "Emet!"). Quite on the contrary -- they
encourage thinking about what the Chazan is saying. They are a hefseq
in the sense of disturbing the matbei'ah, but the responses are only
made by people not trying to be yotz'im with the berakhah, so again I
don't see the problem.

But where it comes to breaking the matbei'ah, the question that comes
to my mind is how firm must the matbei'ah be before it's a problem? Is
the body of a berakhah more solid of a matbei'ah than the body with
the piyut, that we need to ask how it could be disturbed? Shouldn't it
also make a difference if the piyut is inserted between the "me'ein
hachasimah" at the end of the body and the chasimas haberakhah itself?
And what about minhagim to change the chasimah? Do any of these
changes (eg: oseh hashalom) refer to versions that aren't simply
equally old other variants, equally holy matbei'os? (I believe all of
them are, actually.)

SheTir'u baTov!
-micha

-- 
Micha Berger             One who kills his inclination is as though he
micha at aishdas.org        brought an offering. But to bring an offering,
http://www.aishdas.org   you must know where to slaughter and what
Fax: (270) 514-1507      parts to offer.        - R' Simcha Zissel Ziv