Final answer:
The speaker is using a rhetorical device to emphasize the importance of the forthcoming information, not a physical communication device like a microphone.
Step-by-step explanation:
The speaker is using rhetorical device in the statement, "Now we come to the most important thing I have to tell you." This phrase is designed to draw the audience's attention and emphasize the significance of what is about to be said. This technique is not related to the physical devices of communication like microphones or loudspeakers, but rather to the method of speaking effectively. The choice of words serves to create a sense of anticipation and importance around the upcoming information, which is a key part of engaging an audience in any form of speech. When selecting microphones for a production, the decision is crucial and depends on factors such as reliability and sound quality. Wireless body microphones, for instance, are often used in theatre because they are inconspicuous and allow actors to move freely, though they also pick up all sounds and may create noise if not secured properly.