The MegaWorks 550 5.1 consists of four satellite speakers, as well as a central channel, each of which has a power of 70W when measured in Burst mode and not RMS. Add to this a woofer that is as impressive for its 150-watt power as it is for its size. The MegaWorks 550 5.1, like the Klipsch Promedia 5.1, uses the BASH (Bridged Amplified/ Switching Hybrid) and PDC (Primary Digital Control) technologies developed by Indigo. The principle consists of analyzing an audio signal and transmitting it in a digital stream that keeps the output level amplified in such a way that it is always greater than the strength required. The result is a constant level in the current of amplified outputs, making it possible to obtain very powerful sound, yet without distortion. As a final point that emphasizes the difference from the 510D, note that the 550 5.1 has no phase-changer switch. There is a treble-reducing function that completely removes some of the bandwidth problems by using a 3dB reduction at 10 kHz. Note, on the other hand, the huge improvement in the remote control that finally includes all the adjustments that might need to be made to speakers in this range - general volume, center, surround, basses, trebles, mute button, and a very practical headphone socket. The MegaWorks 550 5.1 claims to have a bandwidth of 25 Hz through 20 KHz and a signal-to-noise ratio of 99 dB. As regards the connectors, the digital minijack input is no longer supplied, but there are three analog minijack inputs for 5.1 sound and an auxiliary input, also in mini jack form.

In terms of quality, the MegaWorks 550 5.1 turned out to fulfill every item on the wish list for this roundup. Quite simply, when compared in real time to all the speakers tested in the comparison, these are the only ones to have emerged as being different in every respect. The sound is very true and hardly changed, retaining a great deal of fidelity in comparison to the source. This does not prevent the MegaWorks 550 5.1 from having rather "in-your-face" sound that is okay for games and for specific types of music that require a certain amount of attack. Music tests revealed a fairly pronounced attenuation of the treble, but this could eliminate the risk of saturation at the highest volume. The choice makes it possible to retain good overall bandwidth, but noticeably reduces the dynamics at high frequencies. It could be considered as a positive and innovative option, however, because it limits deterioration of the signal, even if it is not consistent with typical PC usage that often requires more percussion, even at the expense of quality. The medium range sound remains intact, however, and is clear and sharp, benefiting from all the power of the MegaWorks 550 5.1. The bass notes from the woofer are much more rounded than in the 510D, which is no bad thing. The lowest note claims to be at 25 KHz (how is it measured?), but that is something of a joke since it is actually somewhere around 40 Hz, although that is, in itself, perfectly satisfactory. The bass notes are very deep and percussive when they need to be, but without exaggeration. The dynamics are excellent and performed better than all the other equipment in this comparative test. The stereo image and distribution of the instruments are of the same caliber, and there is very little with which one can reproach these speakers as far as quality is concerned.

The tests on games, music, and DVD sound were also very positive and make MegaWorks' 550 THX a must for all these types of use. Such excellence obviously comes at a relatively high price, and the speakers cost $349.99US (€469) including VAT, representing a sizeable investment.