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THX and what it does to DTS sound

Discussion in 'AV Receivers & Amplifiers' started by russraff, Dec 29, 2001.

  1. russraff

    russraff
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    I am a little confused, here, so if someone could help, that would be fantastic.

    I recently bought a Denon A10SE, and have been merrily watching DVD's since :) Several thoughts have occured to me, though:

    The new Planet of the Apes DVD is THX certified and has both DTS and DD tracks. Normally I choose DTS, but if the disc is THX certified, does this mean that the DTS soundtrack has the trebble curtailed a la THX standards? I seem to remember that THX don't really like DTS too much, so should I be even using the THX decode option with DTS tracks or just with DD. I know the last point is possibly a personal preference (I like THX) but it would be nice to know the full technical answer.

    Thanks in advance - Russell
     
  2. rnjones

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    Hi Russell, I am not an expert on this either, but here is my take.

    THX as far as I can see does some "post processing" of the audio signal after it has been decoded by either DD or DTS.

    Acording to my Denon manual and other sources (Home Cinema Choice etc) THX does some re equilisation on the sound track to make better suited to the domestic environment. One of these is to take some of the higher frequencies out which are typically boosted in a Cinema environments because there is a lot more mass (punters) to soak reflections etc.

    I am with you that I prefer DTS on just about every DVD that has the option.

    I have a new AVC-11SR which has THX on it I have listened to quite a few discs and really prefer the THX treatment.

    I have also tried it with DPL II and Sky broadcasts and I think it improves TV sound even more. Really "focuses" speech better.


    I spent some time with R1 T2 which is THX certified and has DD and DTS on it. (THX test are also good as I realised my central speaker was out of phase!!).

    NO chance of DD being anywhere near as good as DTS (THX or not) in this case.

    So I reckon if it sounds good, do it.

    Cheers Rog

    p.s anyone recomend some good THX speakers?
     
  3. ReTrO

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    For THX speakers try M&K. Either the S150 (THX Ultra) series speakers, or the 750 (THX Select). If you don't want either of these I can recommend the 85 series, which are better than the 750's as they share much of the 150s technology. Or if they are all too expensive try the K-series, probably the K3 package with a different sub.


    Good luck!
     
  4. DodgeTheViper

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    Russell ,

    I'm no expert but i'll try and shed some light.

    The THX logo on your DVD package means that the disc has passed a strict set of standards for audio and picture quality.

    The THX logo on your receiver is a different matter. This has also been to the THX labs, but for different reasons. The receiver itself has to perform to the THX characteristics, as it is in here where the 'post processing' occurs. You could almost say that THX is another listening mode.

    Myself, i prefer to have the 'dynamic range'.

    Hope this helps
    Kevin
     
  5. stranger

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    according to the people who produce dvds, the sound is coded to the disc for home use, a lot of reviewers are wrong about these sounds in the cinema issues.
     
  6. BadAss

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    Plus you get some movies in the cinema shown in THX and some not, depending on the cinema. To me THX means each stage has been monitored to perform at a certain (high) level. Although my amp Processor and some DVD's are THX certified my speakers are not so I turn the post THX processing off and listen to straight DD, DTS.
     
  7. russraff

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    I kinda knew what THX does, but was interested in what people did if they listened to a DTS track. I mean, if DTS is better because of its more dynamic headroom, then is seems silly to curtail the treble by engaging THX (even though I think it sounds better). Actually, I remember reading that DD is technicaly superior to DTS, but for some reason people prefer DTS despite its shortcomings. I suppose that I will be right around the twist if Sony ever bring out a home 8 channel SDDS decoder…

    Rnjones: I have listened to and was impressed by (Subwoofer not included – it wasn’t that good) KEF THX speakers. The centre in particular was excellent. Also, if you can find them, Boston Acoustics make some decent THX speakers for somewhat less than M&K and KEF. I personally found M&K too clinical, possibly like what a studio monitor would be like.

    Mozzer: Somewhat bizarrely, though I prefer to listen to a film in THX, I turn it off if I am listening to a music DVD. Perhaps the dynamics of music based DVD’s are encoded more sympathetically for the home audience?

    BadAss: I would have thought the THX processing in your pre/power are just as useful even if you have regular speakers?

    Thanks again for your thoughts - Russell
     
  8. CarlB

    CarlB
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    Russell,

    I have the AVCA1SE amp and M&K 750 THX Select speaker package, with additional M&K SW85's ceiling mounted for the back surround channel in my EX/ES setup.

    For DD films I use DD with THX processing (THX Home Cinema mode), and for DTS movies I use straight DTS with no THX processing. This is because DTS is not designed to be used with THX post-processing on the current AVCA1SE model (or your A10). There is an upgrade to the A1 coming soon which enables THX processing on DTS tracks, but in the meantime if you enable it you will not be hearing the soundtrack as intended.

    I think the 11SR may already have this upgrade and be compatible with THX DTS, but I'm not quite sure. If you're looking for speakers, I have been delighted with the M&K 750 package since I got them in September, and I understand they also use exactly the same drivers as the 150 and 85 range (at least that's what it says in my manual). I can't really fault them, and I think they are a great route into THX spec kit, which I believe works very well despite reservations from many people.

    If you have any more Q's I'll try to help.
     
  9. johnson

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    I have the avc-a11sr.

    In the manual it states the optimium sound mode for 5.1 movies(dts or dd)is with THX post processing.

    However with dts-es discrete or matrix(6.1)it states the optimum mode to be dts decoding with THX turned off.

    It states with dts-es,the post processing "sometimes" gives a more natural sound

    Regards
     
  10. russraff

    russraff
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    Jesus, Thats some system you have there, Carl! What are the Select style of speakers like for music? Better than Ultra rated speakers?

    The DTS thing is what I thought, but I couldn't find it stated anywhere. Still prefer DTS sound with THX on though...

    Russell
     
  11. CarlB

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    Russell,

    Thanks for the comments, I am *really* delighted with the system since I had it installed this year (thanks to a decent bonus). Prior to that I had a Sony / Mission / REL setup and I can really notice the difference now!

    I find the 750 speakers great for music, and the 'Select' range allows direct-radiating rears which are better for 5.1 music applications, though I always listen to CD in 'Pure Direct' 2-channel mode. 5.1 music DVDs sound great though using all channels. I know a few people have complained that the imaging with the M&Ks is not as great with music as purely musical speakers would be, but that is a compromise with the widened soundstage for film that the M&K's generate (thanks to their angled tweeters). I have a sweet spot on the sofa in the room and musically the system is the best I have ever owned, period. I'm not a real audiophile so make of that what you will, but with my Arcam CD7SE I get a fantastic image, tight, controlled bass and superb treble without brightness - I have been 'rediscovering' CDs since September!

    Generally, I think the consensus is that 'Select' speakers are better with music as they relax some of the stringent THX guidelines on vertical dispersion patterns present in the 'Ultra' spec. This is because in smaller rooms the signal does not get chance to disperse as much in the vertical plane before hitting a boundary. I think this means the speakers are slightly more conventional in design and thus somewhat better suited to music than Ultra speakers. I may be wrong here, but personally I have nothing but great things to say about the setup, and most people who've dropped by so far have been blown away.
     
  12. uncle eric

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    Carl,
    The 750 Select range only has its tweeter in common with M&K's THX Ultra systems. This tweeter is used in the legendary 5000, and 150 systems.
    The 750 LCR's midrange units though similar in size are in fact entirely different from the above.
    M&K's S85's and 125's are the lowest priced speakers that share both drivers (Tweeter and Midrange) with their elite cousins.

    If you look at the spec of your S85's you will see they are rated to 400 Watts. The 750LCR's are rated to 200 Watts.

    Eric
     
  13. rnjones

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    Retro, Russell and others thanks for the speaker recomendations. As I already have an M&K Sub, M&K might be the way to go.

    Johnson is correct after reading my AVC-A11SR manual it does say DTS without THX is the recomended mode, my mistake. But I agree with Russell still sounds better with THX on. This may be because my Mission Centre just isn't good enough. Having just blown my wad on the 11SR new speakers are some way away.

    Now I am Waiting for the other half to go out, shopping, anything! So I can do some tests at sensible volumes :).

    Rog
     
  14. russraff

    russraff
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    Thanks for the info, Carl. I just needed to know from a "non dealer" what the select style of speakers were like for music. I have heard a few THX Ultra speaker sets (though not M&K) and thought they were very poor for music, especially the Jamo set. Movies were a different matter, though...

    rnjones: The best centre that I have heard is the KEF THX model. Well worth saving up for. Several people have said the KEF 200 centre is better, but I haven't heard it.
     
  15. Matt

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    Not always true, J'acuse Highlander, a notoriously bad THX branded disc
     
  16. ReTrO

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    I seem to remmember that the Alien discs were THX mastered and had a particually soft picture.
     
  17. uncle eric

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    Also, most THX 'mastered' (mastered not really being the right term for their contribution) suffer from severe EE (Edge Enhancement)

    Eric
     
  18. Rob

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    True. A THX mastered badge on a DVD is certainly no guarantee of a quality transfer. I don't know how they get away with this. I have 2 versions of Twister (OK a bit sad). One is THX mastered, picture is a tad soft and grainy. I then bought the DTS edition. Sound is clearly better, as is the picture, and its not THX certified. I've noticed this in a few other cases as well. It now puts me off if I see it on the case.

    I found I prefered the Kef TDM centre speaker to the 200c, and its considerably cheaper.

    Rob.
     
  19. stranger

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    if THX were really about quality instead of making more money, they would not have lowered standards from ultra to select.
     

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