Yup, that I'm aware of. And nope, don't care for the THX rating on a separate power amp. Picking a good quality amp is easy.
But when it comes to A/V receivers it's a whole different ball game. THX (surround, timber, etc.) algorithms sound fantastic!
THX certificate is also important in an A/V receiver because manufacturers blatantly cheat! Have you seen some of the power supplies where the makers claim 100+ watts all 7 channels driven? They are a joke! Or those that use class D amplification. Or non discrete output stages
I value THX for the following:
- A/V receivers, because I get the fantastic THX algorithms and a reassurance that the receiver will perform correctly as rated for power.
- Center channel speakers. Because it makes sure that it's not just an LCR speaker placed horizontally. Either the tweeter is above the woofers, or it's a proper 3-way design, where the tweeter and upper midrange drivers are positioned vertically and crossed low to the woofers.
- Rear speakers.
- And for the fronts, although much less important in my opinion.