Turning a knob is vastly superior to hunting around in the interface or other software to change the volume. The case of the speakers should also be sturdy. Many people who buy speaker systems disregard this all important feature. Some of the less expensive models have wonderful specifications but lack the sturdy construction which may cause the speakers to prematurely fail, or to simply cause distortions, vibrations and vastly inferior sound. Even the best electrical components need a sturdy case off which to bounce the sound waves.
Sturdy cases can often result in richer and deeper sound.
Another difference in purchasing speakers is the number of speakers provided. The two unit systems are stereo speakers which provide sound next to the monitor which can be divided into right and left channels. A three unit speaker system also provides a sub-woofer, that you can put on the floor under your desk. The standalone amplified subwoofer provides deep, resounding bass and special sound effects that make games and multimedia presentations shine. The six unit speaker systems provide three dimensional surround sound by placing three speakers behind the computer user, in addition to the standard three pieces that flank the monitor and sit on the floor under you desk.