What are "Tziltzelei Shama"?
Rashi: They are cymbals that make a loud noise (Radak - like "bi'Mtziltayim Nechoshes Lehashmi'a" - Divrei ha'Yamim I, 15:19). "Shama" is a noun, like Shema with a Segol 1 . Here it has a Kamatz Gadol due to the Asnachta, and therefore 2 the accent is under the Shin.
We call it Tzeirei, e.g. "chi'Shmo'a Lavan Es Shema Yakov" (Bereishis 29:13), "Lo Sisa Shema Shav" (Shemos 23:1). (PF)
'Therefore' refers to 'it is a noun.' Whenever it is a noun, with a Segol (Tzeirei), the accent is under the Shin, even without an Asnachta. When it is a verb, the accent is under the Mem (PF)
What is the significance of praise with Tziltzelei Seru'ah?
Radak: They make Teru'ah heard. Metzudas Tziyon - they are trumpets.
Malbim: Refer to 150:4:3:1.
