First, there are other considerations, like setting treble, bass and volume. there is setting the sensitivity of the microphone pick up, (how well it "hears" the singer, and at what range) other tools, like adding reverb, suppressing feedback and on and on. Just get a Karaoke machine ( they come with Microphones and even some songs) or use your PC and the karaoke app it likely has as part of its soundcard system, or get one from an app store.
We have warned purchasers before here that such devices as soundbars and HTiB's are limited use appliances, and do not substitute for an AV receiver or other full sound system. They go buy them anyway then immediately after go Hey I cant hook up this or that , cant put the speakers where I want them, cant use it for "X", wont work to give good surround sound, has no radio, sounds beamy and funny, I cant adjust left and right well, (or at all), Wont work with those speakers I got for Christmas, on and on. If you want actual surround sound, and versatility of input, get one. Otherwise, just enjoy your appliance for the purpose it was built.