THX Cinema Mode Explained

Re: THX Cinema Mode Explained

One potential downside, depending on your priorities, is that THX skews the sub in favor of maximum output over maximum extension. Whether or not this is better depends on what you want and the capabilities of your system. It also used to re-equalize the high frequencies to compensate for soundtracks which are mixed for theaters rather than home. I don;t know if this still applies, since basically all home video material is now mastered for home use.

I have had a (full) THX certified receiver for about 10 years, and I haven't used the THX mode for probably 8. I actually don't use any processing modes. I listen to music in "Direct" mode and movies in their straight, unmodified DD or DTS modes. After the initial excitement wears off, I find post processing difficult to listen to.

Re: THX Cinema Mode Explained

My understanding of the "direct" mode is that it basically selects the primary audio codec on the disc. You can still select the others as you've stated, but, "direct" automatically selects either DD, DTS, TrueHD, etc, etc, depending on which has been deemed the primary audio by the discs author.

Re: THX Cinema Mode Explained

Huh? That doesn't make any sense. We're talking about a receiver here, not a Blu-ray player. The setting on the receiver doesn't select the track on the BD player. You do that with the BD player menu. In some cases if using HDMI, HDMI auto-negotiation will cause the BD player to fall back to a default track/core track or PCM if the receiver tells it that it can't handle the particular codec you selected. The "Direct" setting on Sony Blu-ray players (as opposed to the setting on the Onkyo), uses bitstream out for the track so you decode on the receiver, bypassing the decoding/mixing on the BD player.

"Direct" on Onkyo receivers just turns off nearly all post-processing, including bass management from what I've read. You probably shouldn't do this for movies. Some may want to use it for pure CD/MP3 stereo music listening if you have full-range mains. But I wouldn't use it for normal DD/DTS etc.

Re: THX Cinema Mode Explained

This is correct. I have an 805, which I assume has similar processing capabilities as the 806 (at least in this particular situation). The 805 has "Direct" and "Pure" Modes. In both cases the AVR disables all post-audio processing including bass management. Therefore, very few people would want to use either Mode for movies. If you have full range front speakers, then either of these Modes may be OK for 2-channel material.

BTW- - The only difference between Direct and Pure Modes is that when using the Pure Mode the 805 shuts-off the display, and video processing circuits; Direct Mode does not. This difference is poorly explained in the 805 Manual.

As to the OP's original question, I prefer not to use any of the THX or other post-decoding Modes. I just use whatever is the primary HD audio format on the Blu-ray (DTS-HD MA, TrueHD, etc.).

Re: THX Cinema Mode Explained

I use Direct mode on my 806 because i do have full range mains and don't want the subwoofer to be active which is what the case is when using the Stereo mode.

Pure Audio does turn off all video processing but thar isn't something that i need to use when i am streaming through my XBOX360 because then i cannot see what to play.

Re: THX Cinema Mode Explained

John, I think you're confusing THX processing in a prepro/receiver with the THX mode on some subwoofers, M&K being the main proponet that I can remember. The THX mode on those subwoofers would change the subsonic filter and probably apply some other equalization to faciliate meeting the THX requirements. THX didn't mandate a tradeoff of output over frequency extension, but a manufacturer, like M&K, who EQ'd some of their subs to an f3 of 20Hz, could retune that EQ to get that same sub to meet the THX output spec, which only called for extension down to 30Hz in the '90s. Today the THX output requirement extends down to 20Hz.

RE-EQ, the high frequency rolloff curve that was implemented to couteract the boosted highs a theater track exhibited at home, is user defeatable, but defaults to on when a THX mode is first engaged after powerup. Now that audio is frequently remixed for home release, this is no longer the "problem" it was in the '90s when THX standards were introduced and audio tracks were usually transferred straight without accounting for the difference between a theater and home environment. Thus, the mode is not locked on when THX processing is selected. Interestingly, Audyssey RoomEQ's "standard" target curve dials in a similar high frequency rolloff when it measures and EQs a room. This "standard" target is defined for mixing stages by some movie audio mixing standards body. On the Onkyos, if you engage a THX mode and then deactivate RE-EQ, you then get the Audyssey "flat" target curve...no high frequency rolloffs.

The only LFE channel processing THX audio modes do is "boundary mode compensation". This was introduced with the "2" in Ultra2/Select2, I believe. It defaults to off and is selected independently of the THX mode, at least in Onkyo land. As the name implies, it's intended to help offset the boominess that can come from placing a sub too close to a wall(s). Audyssey will likely dial in a compensation of its own, but you can have THX U2/S2 processing without Audyssey and vice-versa.

To the OP's original question. Everybody should listen to the various modes and choose what they prefer. Since I can't see my 805's display, I used "blind testing" to decide on my preferred modes by cycling through the surround modes until I found the mode I consistently preferred. Only then would I check the display to see where I landed. For movies, that ended up being a THX mode a majority of the time...every once in a while, it would be a DPL II Movie mode, but THX modes are mostly just an extension of this so that's not too surprising. For DVD-A/SACD, I like THX Music mode, but for plain stereo sources, I prefer the stereo mode...expansion to 5.1/7.1 can be "interesting", but it quickly sounds gimmikcy IMO.

BTW, I also used this same blind sampling to decide on RE-EQ On/Off. Even though the rolloff is only a couple of dBs at 20kHz, I still consistenly pick "off", even on something like "Planet Earth" (Attenborough, of course) which doesn't have a lot of high frequency information to speak of.

As a final BTW, all of the THX modes and processing are explained on THX's site, just as Dolby and DTS also have text and graphs to show you what effects they're trying to accomplish with their various processing modes.

-Brent

Re: THX Cinema Mode Explained

Some of the absolutes being stated here actually vary with models and manufacturers. For example, the THX mode on my roughly 10 year old, full THX Pioneer receiver does in fact mess with the extension, and the direct mode does leave bass management intact. So, don't assume that because things work one way with a particular piece of equipment they work that way with all equipment. Also, this same receiver does not have the ability to defeat the re-eq when using THX mode. That feature may have become more common, but it was not always the case and is not universal.

Re: THX Cinema Mode Explained

Adam did mention he had an Onkyo and I think many of us, myself included, are speaking from first hand Onkyo experience. I tried to qualify my comments as Onkyo specific, where necessary, although quite a few items should be universal for THX standards.

What Pioneer do you have? I've tried to stay fairly current with public knowledge THX standards since their inception, but I've never heard of any extension fidding happening in a processor under the guise of THX.

-Brent

Re: THX Cinema Mode Explained

Yeah, You're right. I was thinking about the player end of things. That the OP was talking about receivers some how didn't register to me. Thanks Stephen.

Re: THX Cinema Mode Explained

Check out the Audyssey thread for some good information. For example, if you sub is set for -15, then the volume on the sub itself is too high.

Re: THX Cinema Mode Explained

Not all speaker efficiency is alike, some may have a higher output given a set level of power. Your subwoofer, being self-powered, is obviously set to output a very high level of volume for a relatively low level of input. You should turn the sub's internal gain down.

It's probably not a very good idea to "set them all back down to 0 dB". It may "sound fine" to you, but rest assured it is not the way to listen to surround sound. This may not matter to you in the least, and that's fine, but if you really wish to enjoy the hobby of home cinema, then a properly setup system is a good start.

Re: THX Cinema Mode Explained

Just incase you do not know where the Audyssey thread is, below is a link to the Audyssey Setup Guide that is the "Bible" for setting up an AVR that has Audyssey.

"Official" Audyssey thread. - Page 191 - AVS Forum

Re: THX Cinema Mode Explained

FYI - Links to AVS do not work from here. We do have a dedicated thread that Chris from Audyssey visits often. http://www.hometheaterforum.com/htf/...non-et-al.html

Check out the setup guide I reposted here from AVS (with the author's permission, of course).

Re: THX Cinema Mode Explained

Thanks David, I did not know AVS blocked access from other forums (or that any forums blocked access from others). Sad situation.....