Welcome to ASR! To answer your questions:
1. What
@staticV3 said.
2. What your speakers sound like is heavily affected by where you have placed them. Do NOT: place them on a resonant surface, against the wall (unless designed to be against the wall), place them with a large flat surface in front of it (like at the end of a desk), and make sure your ports are not blocked. A picture would help us advise you further.
3. If your source is a computer, you could, as a last resort, use EQ to correct the tone of your speaker if you are unhappy with it. The best way is to use a microphone and measure so you can see where the problems are. Otherwise, you could guess where the problem frequencies are and EQ it by ear. One way is to play a sine wave sweep slowly and listen for any peaks. Take note of the indicated frequency and cut it with EQ. You could use something like EqualizerAPO (which is free).
4. A description of your subjective impression of the sound might help.