A speaker is the last link in the audio system chain, and converts electrical energy in mechanical energy. There's a big difference between good and bad speakers. For the latter, think of what comes built into your TV, mobile phone or laptop. They're so small that they can't move enough air, and that's why the bass really suffers with these. It's sort of like whispering.
Usually, the bigger a speaker you can fit into your system and afford, the better the result you'll get. But size isn't everything! Good, dedicated stereo speakers have a lot of work that goes into their engineering, using physics, cabinet design, materials and electronic components to ensure that the movement of air accurately matches the electrical signal they receive from the amplifier.
We only stock speakers that we judge to have a great sound, coming from reputed audio brands that have invested decades into R&D, and cover the best models across bookshelf, floorstanding, subwoofer, outdoor, in-wall and in-ceiling types. Browse them here.