Buy Analog PA Mixers
A Analog Mixer would be the go to mixer if you need to control a large number of inputs, for example, a Vocals, Guitars, Keyboards and Backing Vocals, A Passive Mixer will allow you to control all of these inputs with overall volume and also Equalisation on each channel. Equalisation or EQ is how you shape the sound of that particular instrument, for example you can remove some of the low frequencies or high frequencies to shape the sound better to the ears.
PA Mixers come in just a 2 channels all the way through to a 32 channel mixer, allowing multiple inputs to be controlled at ease. Some mixers also come with Digital Signal Processors built into them, A Digital Signal Processor or DSP can add reverb and delay to your sound. Normally this would be applied to vocalists to give the vocal a bit of depth within the overall mix.
Passive PA Mixers
Mixers consist of channel strips, they go from top to bottom vertically, and a channel strip gives you full control EQ, or the gain for the instrument. With the turn of a knob or a pushable button these settings can be turned on and off.
the sound that comes out of an Analog PA Mixer is normally changeable for each room, each room will require a tweak from the last room that you played in, The sound engineer or the person in charge of the mixer will need to make sure the levels don’t go into the Red and Clip as this can cause the sound to be distorted and sound horrible.
Knowing how to use the mixer takes time and patience, once you know how to use a mixer its easy to use, and is a key piece of equipment that is required to control the overall sound of your instruments.