Altec Lansing seems to have solved the problem of often producing understated subwoofers by throwing an extra cone into the mix. The FX4021 contains an isobaric subwoofer, meaning there are two sub cones in the box placed on top of one another.

The design may need a little tweaking but for a small, bass-heavy set of speakers, this in essence does the job. During testing, we noticed the large disparity in results we achieved when testing different types of music. The sub really booms, so tight rhythmic patterns often heard in rock and dance music sounded great. The likes of Jet, U2 and The Chemical Brothers really brought out the best here, with constant and intense bass lines proving to be what this sub was designed for.

Testing on slower and more dispersed sounds of funk and soul music gave us very different results. Where bass lines were more subtle, slower and more varied, the sub sounded highly inaccurate. Jumps in bass lines made the subwoofer pound out the notes at completely different intensities one after another, sounding very unnatural.

Aside from the sub, the satellite speakers displayed sound of an average quality. Highs were not overly well defined but mid range and vocals in particular were tight and clear. High volumes were not handled well though, as distortion became quite dominant and the sub began to sound particularly throaty and hollow when pushed to its limits. Some separation issues also became prevalent when the volume was really pushed. We noticed the highs sometimes dropped out when the sub went to work. This was at very high volumes though and was not something evident during normal listening levels.

There are two control options with the FX4021; a wired control unit and a small remote. The wired control unit sports a cool design with a circular volume dial surrounded by backlit buttons for bass and treble, as well as loudness and SFX modes. Loudness essentially just increased the sub output, while SFX widens the sound image, the latter of which we found valuable. The wired control unit also houses a headphone jack and auxiliary input.

Setup was a simple task with all connections colour coded and running through the sub. A dual-to-single RCA adapter is also included to input a stereo image from a CD player or gaming device.

Essentially, the purchase of the MX4021 will really depend on musical tastes. For the likes of rock and dance music, this will give great results and offer a very attractive output for the asking price.