In many siddurim, the text indicates a position, toward the end of each normal paragraph of prayer, where the Chazzan is supposed to start reading aloud, so that everyone knows when it's time to go on to the next paragraph. Does anyone know where these positions come from? Are they from tradition, or just pragmatic choices by each siddur publisher?
Rabbeinu Yehudah Hachasid writes in Sefer Chasidim (reish nun alef) that the job of the Shaliach Tzibbur is to wait until most of the kehal has finished one paragraph and then he starts the next. He says that what we do is a mistake that was propagated by arrogant mishoririm (chazzanim) who wanted to be heard. The correct hanhagah still exists by some groups of chasidim, particularly Karlin.
Not sure. The artscroll "diamond" is believed to be their modification of the crosses found in ... other groups' prayer books.
Printed after the Rambam's Halachot of Prayer are his text of the siddur, which includes some notes of his on what the chazzan says out loud in kedusha.
When it comes to Psukei D'Zimra, you really don't need a chazzan anyhow, it's just to keep pace, so it's less an issue. (I believe Chaim Berlin Yeshiva to this day has no chazzan for psukei d'zimra.) Also less of an issue for many Sephardi communities in which the chazzan reads everything out loud anyhow.
There are a few places where it "matters", but in most cases, it's just the custom (not even a minhag per se) that people follow. Some places where the order and timing actually matters:
- The end of the shema: the chazan repeats [not waits and says later] hashem elokeichem emes [machlokes whether the Chazan should say emes the first time [in which case the 248 words end with ... hashem elokeichem emes. hashem elokeichem, and the second emes is part of emes v'yatziv / emes v'emunhah] or not [in which case the 248 words end with hashem elokeichem. hashem elokeichem emes]. The first seems to be the common custom, although I believe the Gr"a says the second
- Parts of Hallel, where the chazan and the tzibbur have a praise / response segment: the chazan says hodu lashem ki tov / yomar nah yisroel / etc and the tzibbur responds hodu lashem etc. to each.
- shir hakavod (aka anim zemiros) and shir hayichud are examples of places where the chazan and tzibbur also have designated "roles"
This isn't exactly an answer, but there are places where the shali'ach tzibur, by all rights, should really NOT read aloud. For example, in the middle of the "paragraph" Vay'varech David, at the words ומצאת את לבבו נאמן לפניך, which is the middle of a pasuk and therefore not the end of anything.