If you're a bar owner wanting to dip your toe into the field of hosting live music, a great way to do so is by putting on an open mic night. This is a simple way to test the waters, as not only will you get people playing for free – or perhaps just for a drink or two as a reward – but you won't need to set up as much equipment as you would for a full band. The vast majority of musicians will just be playing an acoustic guitar and singing. However, you will still need some sort of sound system.
Here are the components you need for a suitable PA system for your first open mic night.
Depending on the size of your venue, you may only need one speaker. Look for one that's powered, as it will do the job on its own rather than a passive speaker that needs a separate powered amplifier to operate. Many PA systems come with two separate speakers on stands, however, and this can give a more expansive sound even in small bars. Investing in a second speaker also gives you more scope for experimentation if you continue hosting music.
In terms of power, a general guideline is two to three watts per person in the audience, although this is a crude way of calculating what you need. Anything in this region is very unlikely to be too quiet, at least, and perhaps hiring a PA system at first will give you more of an idea as to what's suitable.
The mixer doesn't need to be huge or particularly advanced. You need at least two channels – one for the guitar, one for vocals – but you should find at least four even on the smallest models. Of course, getting a larger mixer means you may be able to use it for bigger gigs in the future. For the time being, extra channels can be useful for adding an additional microphone or two, and for plugging in a music player for breaks between acts.
Typically, you'll need XLR cables for connecting your mixer to the speakers. Microphones might also need XLR cables to connect to the mixer, possibly with a guitar-type jack on one end. Check your mixer's inputs and see what can be plugged into it. You should also get a few guitar cables for plugging in electric and electro-acoustic guitars, plus keyboards and certain other instruments.
For guitars that can't be plugged in, a condenser mic will increase their volume. You'll also need at least one vocal microphone, but it's best to get two in case of duos or if one mic breaks down. Don't forget to buy the right kind of stands for each microphone or you'll end up cobbling something together out of gaffer tape and chairs at the last minute.