A karaoke amplifier is a powered amplifier designed specifically for the needs of the avid karaoke equipment owner. Many are designed for karaoke DJs while some are more designed for home use. They are usually designed to make it easy to connect and take down a karaoke rig and provide many extra features compared to a typical speaker system power amplifier.
These features usually include features that any DJ would appreciate. For example, many karaoke amps are considered hybrid amps because they have functions normally associated with preamps.
One of these features is multiple inputs so you can send audio signals from multiple sources. This eliminates the need for a mixer if you have two audio sources, such as the karaoke source and an iPod for filler music. Many of these devices also include a radio tuner.
A typical karaoke amplifier has enough power to run four or more speakers efficiently. For a good karaoke installation, you need 2 main speakers, at least one subwoofer and at least one monitor speaker. The main speaker and subwoofer work together to get all the sound out to the audience.
The monitor speaker is there so that the singer can hear himself. The quality amplifiers for karaoke and other DJ applications have a built-in crossover, which means that the low frequencies of the subwoofer only go to the subwoofer, which keeps them from the rest of the mix. The best way to run the speakers is to run the mains and monitors on the same channel, as high frequencies do not need as much power.
Be sure to match your amplifier to your speakers and vice versa. You want to be sure that the speakers can handle more power than the amplifier can handle, but not too much. For example, if your amplifier can emit three hundred watts, speakers rated at four hundred and fifty watts would be perfect.
If the amplifier can handle eight hundred watts, a single speaker must be able to handle a thousand. But when you run so many watts, you will probably run several speakers. In this case, add up the wattage for each one to determine how much they can handle. With eight hundred watts, you can run two five hundred watt (or even four hundred and fifty) speakers, or four two to three hundred watt speakers.
The downside of this is buying a subwoofer that is rated for fifteen hundred watts and only running it from a three hundred watt amplifier. You will probably burn out the amplifier and never get a good sound from the speaker because it needs more power than it gets just to produce sound properly.