ANSWER:

Say it silently.

You must not disturb other worshipers by raising your voice in any part of the prayer. 

QUESTION: USTAAD WHEN WE RISE FROM RUKU CAN WE SAY …..HAMDAN KATHIRAN TUIBAN MUBARAKAN FEE IN LOUD VOICE OR IN A NORMAL VOICE AS SOME PEOPLE STOP ME FROM SAYING THE LAST WORDS LOUDLY THEY SAY IT DISTURBS US . BUT I WANT ONLY REWARDS AS THIS IS SAID BY A SAHABI AS THERE WERE MORE THAN THIRTY ANGELS COMPETING FOR WRITING HIS REWARD I WANT TO GET THE SAME REWARD