depends on what series. If they are white there good but really old like12 years. If they are black they are the best ones ever made. the silver ones have alot of problems like overheating and shutting off randomly.

The people that invented the black serious also made xtant then JLaudio now boston acostics amps. If you want PPI go for the all black series.

I use to work for sound advice i know there complete background