http://www.stormcam.org/amplified-microphone/
Is there an easy way to use a microphone with some amplified computer speakers?
I’m looking for an inexpensive way to provide a simple PA for a non-profit organization. It seems like there ought to be a way to connect a cheap microphone to a cheap set of amplified computer speakers. I’ve got some background in electronics so maybe all I need is a source or design for a simple preamp. Then again, maybe there is a set of speakers out there with a microphone input.
I came across the same requirement last week for my church. (I’m an engineer who designs A/V equipment for commercial and broadcast).
Most computer speakers are expecting a -10dBu high impedance signal, the same levels as are output by consumer audio equipment. Most mics are going to have an output in the -60dBu (YMMV). So you will need a preamp that will give a gain of at least 50 dB. If you have resources to breadboard up an amplifier, and know how to design low-noise circuits, you can do it pretty cheap.
But, since time and money are fleeting, I ended up buying a cheap input amp/mixer. Behringer XENYX 502 sells for $45 from BHproaudio.com. There’s also some cheap stuff I found at Guitar Center/ or you can get something from Radio Shack or ebay.
To answer your other question, I found that Anchor Audio has some nice speaker/PA units for $167. (I found a pair on ebay for $38 + shipping).
DIY HARMONICA BULLET MIC ON THE CHEAP