Plugging your keyboard into the PA also has a side benefit in that it will allow you to play stereo sound patches that sound better than mono patches. Now lets talk about the PA or vocal system. This is normally the hardest part of band equipment to afford, but one of the most important parts of the sound. This is why planning your PA purchases is the most important thing a band can do. The most important part of the PA is the power amp.
PA systems take a lot of power.
A guitar player can use 50 watts and sound very loud. A 50 watt PA is way under powered for most applications. A power amp of at least 300 to 400 watts or more is required in most cases. An ohm is a measurement of electrical resistance. All speakers have an ohm rating.