mod·u·late 
/ˈmɑ:ʤəˌleɪt/ verb
mod·u·lates; mod·u·lat·ed; mod·u·lat·ing /ˈmɑ:ʤəˌleɪt/ verb 1 [+ obj] formal : to change the sound of (your voice) by making it quieter, higher, lower, etc.
▪ Please modulate [=soften, tone down] your voice. ▪ Because she doesn't modulate her voice, she sounds the same when she's excited as when she's sad. 2 [no obj] music : to move gradually from one key to another
▪ The music quickly modulates from its original key, changing the mood of the song. 3 [+ obj] : to change or adjust (something) so that it exists in a balanced or proper amount
▪ These organs modulate [=regulate] the amount of salt in the body.
▪ Please modulate [=soften, tone down] your voice. ▪ Because she doesn't modulate her voice, she sounds the same when she's excited as when she's sad.
▪ The music quickly modulates from its original key, changing the mood of the song.
▪ These organs modulate [=regulate] the amount of salt in the body.
— mod·u·la·tion /ˌmɑ:ʤəˈleɪʃən/ noun, plural mod·u·la·tions [count, noncount]
/ˌmɑ:ʤəˈleɪʃən/ noun, plural mod·u·la·tions [count, noncount]
