THX ULTRA vs THX ULTRA2

[IBSTORMIN]

What's the difference between these two. I'm looking at two power amps that are from the same company, have the exact same specs except the earlier model is ULTRA and the newer one is ULTRA2 and weighs 4lbs more (116lbs). I can't find anything that will tell me what had to be different in order for it to be certiffied as ULTRA2. And of course the most important question is: Will I hear a difference?

[Woochifer]

These are nothing more than minimum design specifications. I'm not sure if anything changed in the amp specs. The proof is in the listening and THX certification is virtually meaningless to that end, given that the certification process is entirely based on whether an amp's design is done within certain guidelines and can sustain a specific benchmark performance. It has nothing to do with sound quality. Plenty of amps can and do exceed the THX specs, and I've seen some THX Ultra equipment that was very poorly designed.

[BadAssJazz]

I thought THX Ultra 2 targetted larger rooms (12 ft or larger), of course with the corresponding bump in power spec requirements that go along with that. Not so?

To the OP, you will feel the difference in terms of your pocketbook, but you will not hear a marked difference in terms of sound quality if you're running one of these units. Like Wooch says, you can find a number of components out there that while lacking THX certification, nevertheless, exceed this standard in terms of performance.

[IBSTORMIN]

I thought THX Ultra 2 targetted larger rooms (12 ft or larger), of course with the corresponding bump in power spec requirements that go along with that. Not so?

What I've found out: THX 7.1 with Select and Select2 certification are both for 2,000 cubic feet or less, with Ultra & Ultra2 certification are for over 2,000 up to 3,000 cubic feet. I read an article that says the "2" on both Select and Ultra is both for speaker placement and how the surround is mixed, trying to make one speaker set-up work well for both movies and music. The rear surrounds are set together in the middle back. This configuration gives you both a rear channel for 6.1 home theater by using both rear surrounds as one speaker but for music they send equal volume to both the side and rear speaker on each side. Just like with stereo speakers where it sounds like the singer is directly in front of you, they use this configuration to have it sound like the speaker is in the corner behind you, essentially giving you a 5.1 mix, preferred for music (DVD-A and SACD). That seems to have nothing to do with a power amp as it still has seven channels to drive but would affect pre/pro or receivers only. Am I thinking wrong?