THX processing - on or off ?

[rolski]

The main function of THX, according to the blurb on their website, seems to be Re-equalisation, which (quote) "removes the edgy 'brightness' of cinema sound, accurately adapting movie sound for home playback".
As most, if not all, DVD's are now mixed for home-playback from the outset, and TV broadcasts are surely the same, doesn't this render Re-equalisation unnecessary ?
If you have a DVD with the THX logo, does it mean it's been mixed for home-cinema & you therefore should switch THX off, or does it mean you need to turn it on to bring something back into the mix ?

Timbre-matching :- if you have similar / identical speakers in your surround set-up, this is also redundant, correct ?

Bass Management / Time Synchronisation etc etc :- these are features that aren't unique to THX & are usually set-up independently (and offered on most surround-processors now as standard), correct ?

THX + Ultra 2 + all the other flavours & possible combinations - what's the use of them in my AV32R DP based system ? Aren't they just a standard that's been written to compensate for "sub-standard" set-ups, or set-ups with a significant mixture of components ?

At the moment, I'm going to turn all the THX options off - as I can't see they're needed for CD, or DVD, or TV, but I await any enlightening comments with interest.
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[goodman]

I think you're right on all counts. THX is primarily a set of standards, but the standards are secret, so if you buy THX-approved products, you don't really know what you're getting. Some people say that properly recorded DVDs sound better without the reequalization of THX. Back in the 90's, I was really impressed with the sonic impact of Dolby Digital. After I got past first impressions of all the boom and rumble, I realized that music sounded canned and strained. To me, music on DVD videos, if you listen critically, generally doesn't sound good in DD, with THX either on or off.

 

[bpape]

The re-eq is supposed to help make up for what is lost in the theater when speakers are placed behind an acoustically 'transparent' screen. If you don't use one, don't use the re-eq.

 

[tbewick]

I don't think you should assume that everything is mixed to the same overall level.

The THX certification system is divided up into categories depending on where in the market the component is targeted. There's a basic specification for low-end gear and a higher specification for high-end stuff, obviously. I think it says on the Audioholics site somewhere that THX high-end gear is aimed towards home-cinema for larger audiences. If you buy THX-certified high-end gear, I'm not sure if it's called 'Ultra' or not, but anyway, you can be fairly sure that it'll be very good quality.

You right that the timbre-matching aspect of THX specs doesn't apply to those who already own speakers of the same range.

There's something on the Home Cinema Choice website concerning this topic:

http://www.homecinemachoice.com/articles/hccarticles/techarticles/2000071stAmongEquals/2000071stAmongEquals.php

It states that THX re-equalisation boosts the low-end, as this, in their mind, gives a more exciting sound in the home cinema.

I don't have a THX option on my Denon amp, but it sounds similar to the Dolby/DTS cinema equaliser options that I do have. This does remove some brightness from my system, giving a warmer sound at the expense of some detail.

I've found that some of the DVD's I own are excessively bright, for example, The Thin Red Line and The Back to the Future (DTS) trilogy. Others, such as Star Trek Nemesis and Star Wars: Attack of the Clones, are not.

Personally, I'd play around with the options and use them to suit your personal preferences.