THX Processing/DSP - What does it do exactly?

[kexodusc]

My RX-V1400 and many other receivers with that goofy THX certification come with a THX processing mode or DSP.

Does anyone know exactly what this processing mode "does"? Some just play with the liveness/delay settings etc...I would think THX would just try to be faithful to whatever digital codec was being used, and nothing else, but I could be wrong...anyone know for sure?

[anamorphic96]

This is directly from the THX website and has to do with the THX Surround EX function on THX receivers. Not sure if thats exactly what your looking for. Hope it helps. Here is a link as well.

http://www.thx.com/


Bringing It Home With THX Surround EX
THX Surround EX is the home version of this latest advance in hyper-realistic sound technology. Available exclusively in THX-licensed Ultra and Select Series products, THX Surround EX decodes a back surround signal from the left and right surround channels on specially encoded DVD movie releases. Unlike products offering "6.1" channel decoding schemes, only select THX Certified components adhere to superior performance specifications through the following features.

* Redirects bass energy in the Surround back channels to the subwoofer, ensuring optimum bass performance.
* Requires Re-Equalization™ of the Surround back channels to match characteristics of the front and left/right surround channels.
* Synchronizes the Surround Back Left and Surround Back Right speakers in time and position relative to the listener, providing a seamless surround sound experience.
* Preserves the original sound perspective in soundtracks from older films with mono surround channels by automatically re-directing the surround signal to both Surround Left and Surround Right rather than to the Surround back speakers only.
* Maintains the same technical standards for Surround back channels as for Left and Right channel surround, eliminating compromise in channel separation, noise, headroom, bandwidth and decoding accuracy.

[hershon]

I take it you prefer to watch DVDs in Dolby digital or DTS 5.1 or 6.1/7.1 sound than THX. What does the THX sound for DVD's sound like?

My RX-V1400 and many other receivers with that goofy THX certification come with a THX processing mode or DSP.

Does anyone know exactly what this processing mode "does"? Some just play with the liveness/delay settings etc...I would think THX would just try to be faithful to whatever digital codec was being used, and nothing else, but I could be wrong...anyone know for sure?

[Sir Terrence the Terrible]

This is directly from the THX website and has to do with the THX Surround EX function on THX receivers. Not sure if thats exactly what your looking for. Hope it helps. Here is a link as well.

http://www.thx.com/


Bringing It Home With THX Surround EX
THX Surround EX is the home version of this latest advance in hyper-realistic sound technology. Available exclusively in THX-licensed Ultra and Select Series products, THX Surround EX decodes a back surround signal from the left and right surround channels on specially encoded DVD movie releases. Unlike products offering "6.1" channel decoding schemes, only select THX Certified components adhere to superior performance specifications through the following features.

* Redirects bass energy in the Surround back channels to the subwoofer, ensuring optimum bass performance.
* Requires Re-Equalization™ of the Surround back channels to match characteristics of the front and left/right surround channels.
* Synchronizes the Surround Back Left and Surround Back Right speakers in time and position relative to the listener, providing a seamless surround sound experience.
* Preserves the original sound perspective in soundtracks from older films with mono surround channels by automatically re-directing the surround signal to both Surround Left and Surround Right rather than to the Surround back speakers only.
* Maintains the same technical standards for Surround back channels as for Left and Right channel surround, eliminating compromise in channel separation, noise, headroom, bandwidth and decoding accuracy.

Some additions to this list.

Provides dynamic decorrolation when signal in surrounds is mono.
Timbre matching of surrounds to fronts
Bass Peak manager
Adaptive speaker array(ultra II)
Boundary compensation circuit.(ultra II)

[N. Abstentia]

Wow..and I thought THX was a bunch of useless garbage! Turns out I was right!

[shokhead]

You were right.

[evil__betty]

while still not fully convinced of the benefits of the THX listening mode, I am convinced that any reciever that has THX certification will be able to stand up to whatever you can throw at it and not crap out on you. The testing process is tough at the THX studios, and not every reciever is able to obtain the badge of approval. Either way, I still need more time to listen to movies with THX on and off to see I have a preference.

[shokhead]

How do you suppose recievers made it pre-THX? For me, i've never had a reciever crap out. THX isnt going to make a difference for me buying a reciever if it had it or not. Kinda like DSP modes. Doesnt matter one way or the other.

[kexodusc]

Well, I guess the THX modes are nice to have, but I don't think I've EVER watched a movie with it engaged...I usually prefer the EX/ES processing.

Or Dolby Pro-Logic IIx for 5.1 playback, PL IIx for discrete 5.1 and 7.1 is actually quite interesting.
Also, depending on the movie I thoroughly enjoy a few of the Yamaha's movie DSP's (NOT the audio DSP's). These can really add an element to some soundtracks. Sometimes straight DD or DTS is the way to go though.

I was just curious. Every now and again I take the user manual out...the THX stuff caught my eye...maybe I'll play with it some and report back..

[N. Abstentia]

while still not fully convinced of the benefits of the THX listening mode, I am convinced that any reciever that has THX certification will be able to stand up to whatever you can throw at it and not crap out on you. The testing process is tough at the THX studios, and not every reciever is able to obtain the badge of approval. Either way, I still need more time to listen to movies with THX on and off to see I have a preference.

Does that mean that a $4000 non-THX B&K will crap out just because it does not have a THX sticker on it?

The thing you have to realize it that any high quality receiver will meet and exceed the THX 'standard'. Most companies just choose not to pay for the sticker.

[shokhead]

But THX would like to have you belive the highest standard would be THX.

[Quagmire]

My RX-V1400 and many other receivers with that goofy THX certification come with a THX processing mode or DSP.

Does anyone know exactly what this processing mode "does"? Some just play with the liveness/delay settings etc...I would think THX would just try to be faithful to whatever digital codec was being used, and nothing else, but I could be wrong...anyone know for sure?

At least part of what THX processing is suppose to do is adjust for differences between the listening environment that most movies are mixed for (large, heavily damped auditoriums) and those found in the average home listening environment. I know this subject came up recently on a thread (I think it was the "what speakers are over rated" thread) and I'll just repeat the major point that I made then: THX is much more than an isolated product. To glean the benefits that THX has to offer requires a real commitment on the part of the Home Audio Enthusiast. Much more of a commitment that most are willing or able to make. It requires the selection of proper gear (not just the receiver), painstaking setup, and a great deal of attention to the listening room. Not only does it require a lot of work but it is very expensive too. To really evaluate the value of THX, you need to be able to actually hear a properly setup system. One of the nicest sounding HT systems I ever heard was just such a system. Interestingly enough, the optimization for HT purposes via the THX setup made it a very poor sounding music reproduction system. Just different requirements.

I don't have a THX system and probably never will. But I also know that it is easy to bash THX products when listening to them "out of context" and this is how most of us have heard them presented. A THX receiver does not a THX system make. It truly is a situation where the whole is greater than the sum of its parts. Just some food for thought.

Q

[Sir Terrence the Terrible]

At least part of what THX processing is suppose to do is adjust for differences between the listening environment that most movies are mixed for (large, heavily damped auditoriums) and those found in the average home listening environment. I know this subject came up recently on a thread (I think it was the "what speakers are over rated" thread) and I'll just repeat the major point that I made then: THX is much more than an isolated product. To glean the benefits that THX has to offer requires a real commitment on the part of the Home Audio Enthusiast. Much more of a commitment that most are willing or able to make. It requires the selection of proper gear (not just the receiver), painstaking setup, and a great deal of attention to the listening room. Not only does it require a lot of work but it is very expensive too. To really evaluate the value of THX, you need to be able to actually hear a properly setup system. One of the nicest sounding HT systems I ever heard was just such a system. Interestingly enough, the optimization for HT purposes via the THX setup made it a very poor sounding music reproduction system. Just different requirements.

I don't have a THX system and probably never will. But I also know that it is easy to bash THX products when listening to them "out of context" and this is how most of us have heard them presented. A THX receiver does not a THX system make. It truly is a situation where the whole is greater than the sum of its parts. Just some food for thought.

Q

As a person who has installed and tuned THX setups, I'd like to add these comments.

Where I really think THX is a huge benefit is in the room acoustics area. Though the standards they have adopted for the THX program are not unique to THX(they were adopted from SMPTE standards) If followed to the letter, you can stick any HT setup in the room and it will sound great.

My beef with THX lies in multiple levels of processing that is not really necessary. The system as a whole must be eq'd. Then you have re eq applied to that. Then you have timbre matching, dynamic decorrolation, Adaptive array and boundary compensation circuit to send the signal through. That IMO is way too much processing.

Their goal it to tailor the sound made for large theaters to a small room. The problem is that most studios these day already do that(think Disney enhanced for hometheater or New Line releases).

Another issue I have is with them using mismatched speaker for the front and rear. There is no way(without heavy EQ) that you are going to make a narrow dispersion speaker sound like a highly reflective one. You cannot make two speakers sound like 8 or 12 no matter how much decorrolation and delay that you use.

[Sir Terrence the Terrible]

Last night I had a couple of co workers from the station over to watch one of my favorite(and theirs also) movie League of Distinguished Gentlemen.

After a beer or two and just before the movie the conversation came up about how my system would stack up to a THX system. My obvious answer was it would smoke it. If my speakers were submitted to THX for certification, they would easily pass. So then the conversation roams over to THX certified equipment and processing. Since I have a THX certified reciever we decided to do a blind test on each other to see if we could guess if the processing was on of off, and what were their observations on what it sounded like.

So I covered the face plate with black electrician tape, and I was the only one who knew when the switching would be done.

Comments with THX off;

Soundfield is very big, wide and deep, imaging extremely sharp you could almost trace pans with a pencil, bass is deep, floor shaking and extremely powerful. Highs were very sweet and smooth, midrange very clear, and dialog also very clear.

THX engaged;

Soundfield still very big wide and deep, but everything within that soundfield has become fuzzy and blurred. Bass not as powerful or as deep, surrounds sounded like they have disappeared, everything sounds fuzzy and not clear, pans are very smooth, highs sounded rolled off.

Now I have got to admit, engaging the THX circutry changes everthing in my system. I run all of my speakers on large with the LFE going to two 15" subs. THX makes all of the speakers small, and sends all bass to the subs.

IMO the THX should have the advantage, but it apparently doesn't based on the comments of these two guys. I'll admint, I have had this receiver for more than three years, and have never really tried the THX mode.

This was not a scientific test, but a blind test to hear comments on the sonic effects of THX processing. Neither of my two co-workers really liked the sound at all, especially when compared with non processed sound.

[shokhead]

So in a round about way,THX is like a DSP mode?