From Longman Dictionary of Contemporary Englishproject your voiceproject your voiceTALK/MAKE A SPEECHto speak clearly and loudly so that you can be heard by everyone in a big room → project
Examples from the Corpus
project your voice• The use of the microphone helped to project her voice.• Now DeCicco can project his voice, balance better and use his hands.• There are innumerable books on public speaking, dealing with everything from how to project your voice to what to wear. 