Nice woof. Nice tweet.

I needed to upgrade the speakers used on my home PC as the bass driver in the old units was past it's best. Mind you they were 11 years old, so go figure.
I cruised up and down the aisle in BestBuy listening to all the offerings from the $19 own-brand stuff up to the $300 5-channel Bose offerings. It's difficult to learn anything about speakers from listening to them in a shop environment, especially a noisy BestBuy type store. But one thing you can be certain of - you're listening to them under the same conditions, so it follows that what sounds good there ought to sound good at home. Of all the speakers, I settled on these VS4121's because to me they sounded better than all the other speakers there, including the $300 Bose ones. I looked at the VS4221 units which are the next one up in the range but they were double the price and I didn't like the controls on them. Apart from that, the bass unit had the exact same size and specification, so apart from a slight design difference in the bass speaker cabinet, I suspect the VS4221's are identical to these cheaper VS4121's.

The controls on the VS4121 are simple, easy to get at, and all on one speaker - the right one. There's an overall volume control as well as adjustments for bass and treble.
The wiring is mercifully simple on these units, if not a little short. The left speaker plugs directly into the bass unit, as does the line-input from your sound card. Both these plugs are 3.5mm audio jacks. The right speaker has a meaty cable with a PS/2 plug on the end which feeds sound out to the speaker as well as carrying power, bass, volume and treble controls back to the bass unit. This cable is a little short for my liking and being thick, it's also less prone to bending so even after a week, it still has a tendency to kink in the same places where it was folded in the original packaging.

In use the speakers are fine. Putting the bass speaker in a corner gives a nice response without sounding wooly, and the higher tones that come out of the two desktop speakers are nice and clean. Crank up the volume and the whole house will hear you with these speakers although the design of the bass speaker is such that a lot of the bass gets lost when you leave the room (ie. it doesn't carry) - not a bad thing in my opinion. I've ended up with my treble set to about +20% and my bass set to about -10% as best as I can tell from the unmarked controls.

One thing I have noticed with these speakers is that when I plug anything into any of the USB ports on my PC, monitor or keyboard, I get a bass "whump" out of the bass speaker. I thought it was just my PC so I took the speakers and plugged them into my wife's new Dell and they did the exact same thing. I guess the bass speaker has a particular sweet spot that corresponds to the slight spike in current or something. Either way it's not anything to be too bothered about.