Is it permissible for the imam to say "Ameen" quietly during the prayer?

The questioner : ... I know the principle is that he must recite it aloud and raise his voice... Many people's lips barely move with the word: ...?

The Shaykh: How is the last sentence?

The questioner: I mean, my father says... .

The Shaykh: No, it is a great loss; because the Messenger (peace be upon him) used to say: .

The questioner : ... .

The Shaykh: One by one. So what happens to the one who does not say "Ameen"? He misses out on this virtue. Let us move on; some people say "Ameen" quietly and some say it aloud. It has become the stronger position that the people behind the imam saying "Ameen" aloud is better, for several reasons; among them is his saying (peace and blessings be upon him): . What does it mean that the Jews envied the Muslims regarding the "Ameen" and the greeting of peace? That is because Islam was distinguished by many legislations over the previous religions, even before the distortion took hold of them. Among these is the lawfulness of giving the greeting of peace, and there is no doubt that giving the greeting of peace is not done quietly but rather aloud. So its being aloud is what characterizes Islam with a manifestation, or as they call it, a display, that has its effect on other people. Therefore, when the Jews knew that this legislation was something their religion lacked and they approved of it in their hearts, the Jews envied the Muslims for this greeting of peace.

The questioner: The Muslims.

The Shaykh: Excuse me, the Jews envied the Muslims. I want to get to the point that if the "Ameen" were said quietly, there would be nothing to stir the envy and jealousy of the group... . So the point is that here there is an indication that the "Ameen" of the Companions was said aloud, and this was one of the causes of the Jews' envy being directed at the "Ameen" of the Muslims behind the imam, just as the Muslims' care for giving the greeting of peace and spreading it among themselves was one of the causes. Therefore, the stronger position is that the "Ameen" of the followers is to be said aloud, like the imam.
Then, from the wisdom, the Sunnah came to confirm that the imam says "Ameen" aloud. There is no doubt that this "Ameen" is for the purpose of achieving the aforementioned command in the hadith: . So if a person says "Ameen" however it happens, before the imam or after him, he does not get this reward. Therefore, we advise the followers, always and forever, to pay attention to the imam's recitation first, then pay attention to his completion of the "Ameen" second, or the correct meaning of his beginning of the "Ameen" second, then you say with him: ; because in this case the angels say with the imam: , . So for the follower's "Ameen" to coincide with the imam's, it is not possible except that the imam says aloud; here they have to follow him, and it must be aloud.