I used to own a pair of Parallax speakers that I bought new (demos, actually) in the late 70's or early 80's. I don't remember the model number, but they were a three way, four driver system with circuit breakers and a 15" woofer. As a poor man's hard rock/rap (before there was rap) speaker, they were okay, but they were cheap and you could tell from the look as well as the sound. For the money, they were good at hard rock, but they were not good in absolute terms, even for hard rock. Now, I have no idea if the company made good speakers in its past or not, but the ones I had would not be worth getting, unless you got them real cheap and could not afford anything better, and your main interest was hard rock/rap.
On a side note, my demo pair cost me about $100, and about a year later I was able to sell them for what I paid for them. So, I cannot complain about my experience with them. I am certainly glad I can afford better now.