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?
Best Answer
A horn can increase the loudness remarkably. It does it in 2 ways:
better acoustical matching between the air and the speaker cone increases the power of the soundwave
the directivity concentrates the acoustic power to smaller sector. The in-beam dB levels can be much higher than the average or off-beam levels at the same distance.
The horn is that effective only if it's designed for quite narrow frequency range. A single frequency horn can be much more effective than one designed for example reproducing speech understandably.