Any mantra can be chanted in 3 ways --- vachika (loud), upanshu and manasa (silent chanting in the mind). Among these the loud one is regarded as the worst and the completely inaudible one as the best --- https://hinduism.stackexchange.com/q/22632/4732
– RickrossApr 22 '22 at 13:24
It is prohibited. when guru imparts mantra to shishya, guru implicitly takes on the sins committed by shishya. how? when shishya commits sins, he does prayaschitta by doing gayatri mantra i.e. paap balance gets transferred from shishya to mantra-devata's account, who in-turn transfers it to the guru who imparted that mantra. that means whoever is responsible for playing the mantra on loudspeakers takes on sins of whoever hears and repeats it. nowadays, women (including menstruating), shudras, mlecchas all seem to chant gayatri like a cinema song. this disrespects devata @Rickross
– ramApr 24 '22 at 15:38
this is evident in the actual upadesa of gayatri mantra during upanayana ceremony where a white silk cloth covers the head of father, son & acharya during mantropadesa. mantras are called ashadkarna ("not 6 ears"). meaning only 2 people (4 ears) are allowed. in upanayana, only father-son is allowed, but nowadays since father himself may not remember gayatri mantra, the purohit is used as a intermediary. @LSSJBroly
– ramApr 24 '22 at 15:43
You are saying if playing it in loudspeakers is ok or not but I was saying about whether chanting it aloud is ok or not @mar
– RickrossApr 25 '22 at 07:21
@Rickross - same thing. chanting loud is a loudspeaker hearable by 10 people. loudspeaker is hearable by 1000.
– ramApr 25 '22 at 21:38
But chanting Vedic mantras loudly is allowed .. if you don't want others to hear the recital then it's your responsibility to control the environment. @mar
– RickrossApr 26 '22 at 07:18
@Rickross - chanting it loudly is allowed when certain types of people are within earshot. "it's your responsibility to control the environment" - correct, that's what i'm saying. if you can control who can hear you, then say it out loud. if you cannot, then don't say it out loud. if you still say it out loud, then be prepared to accept the sins of those repeating what they heard from you.
– ramApr 26 '22 at 17:13