First goal of the network box is to eliminate the antennae effect by attenuating frequencies above 1mhz. According to Transparent this reduces noise ad hash and removes hardness from the sound. Additionally the cable can be calibrated to matchelectrical values regardless of cable length. For example, a long cable will have identical filter characteristics to a shorter cable, so they sound essentially tha same. Networks also help maintain a common family-voicing. Finally, the network will add some inductance which benefits the frequencies below 2kHz.
In practice, what happens is that Transparent cables have a very distinctive house sound which is probably co-produced by the network boxes. This housesound is characterized by a fluid, smooth presentation that I happen to like a lot. It could very well be a side product of the filtering employed but be that as it may, the result is impressive. The filtering this time doesn't result in softened transients or rolled off highs. In fact, I feel that Transparent cables have better air than many other cables. It's just that the midrange and lower highs are so free from grain and aggression that some people feel that the cables have rolled-off highs. But I disagree. I do think that Transparent cables are best used in well-balanced and open sounding, detailed setups.
The latest MM generation employs solid core copper and for the first time the house sound is modified somewhat. The new cables sound faster, more dynamic and less creamy rich than the older generations.
Cable networks are now more accepted than some time ago but still may people are sceptical. I have to admit that originall I was sceptical, too. After all, didn't filters soften transients and reduce high frequency response? Not neccesarily, as it turns out.