Talk louder than you think you need to or are comfortable doing.
If you are not comfortable speaking louder, then you almost certainly need to!
Always use a microphone if you are offered one, even if it’s a smaller room.
Your voice through the speakers may seem loud to you, but makes it so much easier for others to hear you and have their attention on you and nothing else.
You just don’t know who is in the room.
People in your audience could be easily distracted, have difficulty hearing or a host of other reasons to not give you their full attention.
I was at a networking event the other day. It was a smaller group of less than 30 women in the room seated at 5 round tables. The tables filled the room. The speaker went to the front of the room when it was her time to speak, and when offered the mic said she doesn’t usually need it. I disagreed since it wasn’t that easy to hear her already and I wasn’t that far away. I encouraged her to use it. She did and it was a good thing she did! She was not as loud, energetic or dynamic as it sounded like she fancied herself to be from some of the things she said. Hearing her voice over the speakers made all the difference. Otherwise, I’m afraid I would have been the distracted one since she would not have had my full attention!