Q. Re – above question (2542). When repeating the amida, Halacha requires that we must have at least nine people listening to the shaliach tzibur and answering amen to his brochos., otherwise the blessing may be in vain and prohibited. How much is the minimum of attention needed to comply with the requirement of listening to the shaliach tzibur when the repetition of the amida is recited?
A. Some have argued that even when not consciously paying full attention to every word recited in the repetition of the amida, since the intention in principle is there and just the mind wanders off, as is most common in our days, one may still comply.
The argument follows the fact that we do many activities, and some of them where our attention is most crucial, such as driving fast a car for hours on a highway, without actually placing all of our attention constantly on the act.
However, Horav Shlomo Miller’s Shlit’a opinion is that the subconscious attention may be effective when one is doing an act, such as reading the megilah or complying with another mitzva activity. But when the activity is just listening, as in chazoras hashatz, full conscious attention is required.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a