A common subject that pops up when working with customers; why do I need a separate karaoke system from my home theater system?
The straight answer is that your home theater system isn't made for karaoke. Specifically the singer's microphone audio.
A home stereo system is a digital sound system designed to support various surround sound setups while distributing a constant, but relatively low power handling to all connected outputs.
Because of this, the average home stereo system reduces audio quality in favor of volume, but tends to do an okay job bringing some of that quality back. So yes, your home stereo can sound nice and loud, but audio quality will drop as you increase the volume.
When it comes to a Karaoke Amplifier, which is an analog sound system, its made to power up to two front speakers and tends to work with a large power bank rather than a fixed, low constant. The high power handling allows the system to put more power into audio quality, allowing you to utilize higher volumes without quality drop off/distortion. However, it's recommended that you also get an accompanying set of speakers that are capable of working with the higher power handling.