The sub woofer used in the S4 MidiLand 8200 is one of the biggest I've ever seen for a computer sub. The sub itself is a 6.5" poly cone in a tune port enclosure. The port is tune for 40Hz. That's low enough to shake the walls of your house. Another reason for the enclosure size is the amp is also housed inside, as are the controls for the master volume and all the speaker connections.
The satellite speakers used in the S4 MidiLand 8200 are 3" full range speakers. The proper name to call them are single point source transducers. The speaker is housed in a sealed enclosure that's quite a bit larger than the satellites used in the Creative DDT2500. You will notice the back of the speaker includes plugs for the speaker wire and a screw hole so you can screw the speaker into the optional wall mount kit. Right now MidiLand is offering free wall mount kits with the purchase of the S4 MidiLand 8200.
Having only one speaker to do the frequency above the bass has a few advantages. The main one being it's a single point source. This can greatly improve the staging and imaging for the sound system. The down side is that most single point source speakers can't reproduce the full range of human hearing. While MidiLand claims 70Hz to 20Khz, our measurements show a big drop off above 15Khz. This shouldn't be a problem with music or games as very few sounds effects go up that high.
I won't spend too much time with the ADS 2000 since it has already been reviewed. I will just say that this is one of the best if not the best Dolby 5.1 decoder for the computer.