I need to make a speaker that is capable of creating several tones for a school project, so nothing too big nor expensive.
I'm using a micro controller sending a frequency to a transistor and the transistor is connected to 12v and the speaker.
The sound level must be a minimum of 80 dba in a 2 meter radius. I could only achieve 70 dba with a 3W 8 ohm speaker salvaged from an old radio.
How can I make it louder? Should I change the type of speaker?