Loud prayer on Rosh HaShanah and Yom Kippur

Hi,

Ordinarily we say that one should recite the Amidah silently, mirroring our ancestress Chanah's silent prayer, keeping our personal admissions of sin private, recognizing that Gd is aware of all thoughts - even silent ones - and avoiding disturbing others.

However, on Rosh HaShanah and Yom Kippur many pray in a slightly louder voice, to help awaken their own concentration. This heightened concentration outweighs the reasons to pray silently. As far as disturbing others, we are less concerned on Rosh HaShanah and Yom Kippur, when everyone uses a machzor.

Of course, one must still avoid being loud enough to disturb others.

(Shulchan Aruch Orach Chaim 582:9)

Have a great day,
Mordechai