double click the speaker icon in the lower right hand of the screen
lower the volume of the computer
raise the speaker volume control
if the computer volume is too high, the speakers will sound distorted.
There are 3 controls that your you should match, one is the source; must be set to 75% to 80% volume, second is your computer master volume should start at 50% and third is your speakers must be set to 30% volume to start then start increasing it up to 75% anything higher may result the sound to be distorted, unless your speakers are a "very high quality speaker system". Increase all volume controls later up to thier optimum level if permits.
Problem with computer though is that, the driver may have not install properly or other settings are on in effect. Disable all sound enhancements you have on under sound properties.