The "How many speakers do I need" question comes up all the time, but there's no easy answer. For music a single speaker placed just about anywhere in the room might get the job done for background listening, even for some of my more astute audiophile pals.
When music isn't the prime focus, like while showering, working, exercising, etc., one speaker can be more than adequate if it plays loud enough and has enough bass. Theis one of the best I've heard, but for more attentive listening I'd still recommend a more traditional system with two speakers and a stereo amplifier or receiver. The speakers and a receiver would be a great place to start.
For movies and TV, people love sound bars for a lot of good reasons: they eliminate most of the wiring and setup hassles associated with traditional 5.1-channel home theaters; sound bars don't take up a lot of space; they're less expensive than subwoofer/satellite packages; and since most sound bars are self-powered, you don't need to buy an AV receiver.
A skinny sound bar positioned under a sleek display is a more appealing solution than a 5.1 system or even stereo pair of speakers. There's just one problem: sound bars can't fill a room with sound nearly as well as separate speakers can.
Thing is, I've noticed a trend in sound bars, more and more feature separate surround channel speakers, and of course most sound bars come with wireless subwoofers. So where sound bars used to mean just one speaker we now have some top models that have four speakers: the sound bar, sub, and two surround speakers. The Best Sound Bars of 2017 list.is one of CNET's top rated four-piece sound bar systems. But if you want just a sound bar, with no sub or surround speakers, no worries, the is worth considering. For more great options look at CNET's
Bluetooth speakers are getting better all the time, but so are stereo speaker based systems for music. For movies no sound bar, even ones with separate surround speakers can approach the sound quality of a top notch AV receiver matched with five or more speakers, and a subwoofer. Sorry, it's not even close.
So if you prioritize sound quality for music and/or movies invest in the best stuff you can afford. You'll never regret it.