PASSIVE: But still capable of annoying people
Passive speakers are the simplest and lightest.
Most speakers use a two way setup with a horn for high end and a cone speaker in 10”, 12”or 15” for bass. The bigger the speaker and cabinet, the more efficient and lower frequency possible. But you have to move them too, so watch the size and weight.
Consider using only one bigger speaker for singles and duos.
Browsing the big online retailers, I saw a lot of used speakers that belonged in the dumpster. Avoid anything over ten years old.
You also need speaker wire. Some instrument cables have the same connectors but shouldn’t be used. Don’t buy speaker wire until you know what kind of connectors your speakers and mixer use. They could be XLR, 1/4″, or speakON SPX.
How to Buy Speaker Wire
Speaker wire is sold by gauge, 16g minimum, 14g or 12g. Bigger and heavier is better. Buy ones that are long enough. Don’t forget to add cable length from the ground up to the speaker. Cost will keep you from buying too much, but consider it part of your speaker investment. Try to make 25ft or less work, also because of power loss.
What Makes Passive Speakers a Good Option?
The powered mixer you will need to buy to go with the speakers will have all the electronics in one package, and you’ll only need one wire to each speaker. Make sure the speakers can handle the mixers’ output. The best investment in your system is bigger speakers that can handle more power. They always sound better. It’s easier to do less with more. (Avoid my tendency of overkill.)