1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

To THX or not THX

Discussion in 'AV Receivers & Amplifiers' started by KAO, Feb 20, 2001.

  1. KAO

    KAO
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    My amplifier (PIoneer VSA-E07) has a 'THX Cinema' setting. I've read the blurb at the back of the manual about what it's supposed to do. My question is, should I be using this setting to watch DD/dts DVDs, or should I just use the 'Standard' setting? I have tried both and although there is some noticeable difference I have to say that I can't decide one way or the other.

    Keith
     
  2. dUnKle

    dUnKle
    Well-known Member

    Joined:
    Jan 1, 2001
    Messages:
    13,379
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    136
    Ratings:
    +1,325
    This is something I asked Martin Stoke numerous times and at the end of the day it comes down to personal prefernce.

    The THX modes on amps ( my Denon A1D included ) is basically nothing more that another DSP, all be it one with probably more thought and reason behind it.

    I find that for Pro-logic viewing I always use it and tend to use it also for all DD5.1 stuff as I prefer the slightly cleaner sound that it gives for dialouge, however you do loose some of the more detailed treble sounds. I do not use it for DTS
     
  3. mart.stokes

    mart.stokes
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    I don't use it, I think it is fair to say that a THX amp offers two main things; 1) THX processing 2) a certain level of quality because it is a THX certified amp.

    I have a THX amp (same as Duncan's) and love the sound without THX mode engaged, I find the treble roll-off takes some of the "bite" away.
     
  4. Jeff

    Jeff
    Well-known Member

    Joined:
    Jul 13, 2000
    Messages:
    5,489
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    Basingstoke
    Ratings:
    +256
    I have the Denon AVC-A1SE and I you THX mode for everything except CD's. It sounds smoother to me, I like it. I even use it for DTS ES stuff which is a bit controversial, but hey my ears prefer it.
     
  5. russraff

    russraff
    Active Member

    Joined:
    Aug 1, 2000
    Messages:
    2,311
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Newcastle
    Ratings:
    +50
    I agree 100% that to use THX comes down to personal opinion, and as such here is mine:


    I have recently had a home dem of the A1D. I was thinking of upgrading and was interested to see what difference THX made. I must say that it works wonders with pro-logic, as THX was originally designed to do. However, THX completely ruins both DD and DTS soundtracks, which is probably because THX removes an awful lot of high frequency information in order to tame overly bright soundtracks. Now, in the past there may have been a need to use this process (Re-Equalisation), but modern DVD?s just don't need it. Re-Eq dulls the sound, and, as mart.stokes said, "takes some of the bite away". I'm certainly not getting at anyone in particular, but I find it strange that people applaud DD/DTS for their dynamic, detailed sound, yet insist on engaging THX in order to tame the very thing that makes DD/DTS good in the first place.


    Personally, I think that THX is a process designed in the past, which has no modern application in the home. I wouldn?t use it.


    Russell




    [This message has been edited by russraff (edited 24-02-2001).]
     
  6. Jules

    Jules
    Well-known Member

    Joined:
    Oct 11, 2000
    Messages:
    5,052
    Products Owned:
    0
    Products Wanted:
    1
    Trophy Points:
    133
    Ratings:
    +721
    I disagree.

    I have an AVC A1D, and think that THX works wonders on Dolby Digital material.
    If you compare a soundtrack CD to the same soundtrack on a DVD film, the DVD sounds way too bright. THX sorts this out just nicely.

    I do think that THX works better with DD than it does with DTS, but either way the sound often needs taming.

    I would be interested to know which films on DVD have already been re-eq'd, because I havn't noticed an overly dull sound with any yet!
     
  7. BadAss

    BadAss
    Banned

    Joined:
    Feb 2, 2001
    Messages:
    2,967
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    England
    Ratings:
    +182
    Ive noticed all DVDs seem duller compared to Laser Discs both using DD sound tracks. Take Heat for example, the base and treble seem much tamer on my system and thats without THX engaged. Thats comparing a Pioneer 925 LD player to an Pioneer 737 DVD player.

    ------------------
    Is he the one?
     
  8. russraff

    russraff
    Active Member

    Joined:
    Aug 1, 2000
    Messages:
    2,311
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Newcastle
    Ratings:
    +50
    Jules,


    Actually, I was comparing the Gladiator soundtrack on CD (through a separate CD player) to the score on DVD. Things like the march into Rome and some of the more emotional scenes, for example. The CD contained far more information, as you'd expect, but it also had a brighter sound than the THX'ed soundtrack. The brass instruments in particular were much more defined and "airy" on CD than DVD. It was this more than anything that pushed me against the THX ethos.


    As an aside, I have just purchased the new HCC mag. Interestingly, there is an article by the late Bob Tomalski who is interviewing a Sony representative about THX. It makes for good reading.


    Russell





    [This message has been edited by russraff (edited 24-02-2001).]
     
  9. Gary Palmer

    Gary Palmer
    Standard Member

    Joined:
    Jul 17, 2000
    Messages:
    328
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    16
    Ratings:
    +1
    KAO,

    I think that when THX was applied to HC it tried to address several problems in movie sound reproduction at home (dunno about THX certification of cinemas).

    One was that in a cinema the centre speaker is behind the (perforated) screen which tended to dull the treble. To compensate, when mixing the sound track the centre channel was given a treble boost.

    That meant that playback at home (usually a centre speaker on top of a telly) produced a dialogue channel that was too trebly and harsh. THX re-eualises or tames this treble boost.

    So, THX re-equalisation was a way of compensating for the original compensation.

    I suspect that modern DD5.1 soundtracks don't have this centre channel treble boost which is why so many people think it dulls the sountrack and removes the bite. You probably are taking something away.

    I never use the THX mode on my amp for DVD or SKY because of this (although some crappy SKY channels seem to benefit from it).

    If you've got very bright speakers/amp then THX can help to tame it.

    The rear spreakers are treated to decorrelation in THX mode to produce a more diffuse sound-stage. Good for pro-logic/THX material ; probably not to most peoples taste for discrete stuff like DTS/DD.

    Like all things HC related - it's not right or wrong.

    If you perfer it then it's right.

    :)
     
  10. Confucius

    Confucius
    Active Member

    Joined:
    Feb 1, 2001
    Messages:
    2,103
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Oxford
    Ratings:
    +90
    Gotta say I'm not overly impressed with THX processing as a whole, though I do use the dialanorm feature for the centre channel. What is important (to me) in a THX amp is stability into difficult loads. THX power amps (and AV amps) are tested into 3.2 ohms continuous.
     
  11. Stuart M. Robinson

    Stuart M. Robinson
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Gary Palmer wrote:

    "One was that in a cinema the centre speaker is behind the (perforated) screen which tended to dull the treble. To compensate, when mixing the sound track the centre channel was given a treble boost."

    This is a fairly common misconception. The human ear is less sensitive to distant high frequency sounds than it is near-field high frequencies, so in large theatres and mixing stages (all of which have a frequency response spectrum known as the X-Curve), high frequencies appear to be attenuated. Therefore, when mixing engineers produce motion picture soundtracks they artificially boost the high frequency element.

    When replayed in the home, where the listener and loudspeaker are only separated by a small distance, movies sound overly bright as a result. All three front channels are affected, not just the centre.

    THX Re-Equalisation is based on real and subjective measurements obtained from experiments conducted using a cross-section of recording engineers who were asked to re-equalise a soundtrack so that it sounded 'flat' in near-field conditions.

    Some projection screens do attenuate high frequencies yet further, which is why manufacturers sell post-processors to invert part of the THX Re-Equalisation process, a sort of middle-ground between fully-blown Re-Equalisation and none at all.

    Unfortunately, some DVD soundtracks are pre-equalised for the home (and often the LFE levels are also altered) and this really throws a spanner in the works, especially as pre-equalisation is not indicated upon any DVD packaging. We do however, know that no THX mastered software has been pre-equalised, for obvious reasons.


    Stuart M. Robinson
    SMR Group – http://www.smr-group.co.uk/
     
  12. Gary Palmer

    Gary Palmer
    Standard Member

    Joined:
    Jul 17, 2000
    Messages:
    328
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    16
    Ratings:
    +1
    Hi Stuart,

    I stand corrected :)

    I thought that cinemas and big night clubs used fancy equalisers to produce the correct in-room response rather than messing with the films sound-track directly. I always thought that part of THX certification for cinemas was to make sure that this type of equalisation was setup "within spec".

    Maybe HCC should do a technical article on what really constitutes THX (at home and in the cinema) - especially now that it is being splashed all over the place (laptop PCs ???!!!).

    Whilst they're at it how about an explanation of Sony's dynamic whats-it (SDSSSSSS). Never see that explained.

    Thanks for the info.
    Gary

     
  13. Stuart M. Robinson

    Stuart M. Robinson
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Gary,

    "I thought that cinemas and big night clubs used fancy equalisers to produce the correct in-room response rather than messing with the films sound-track directly. I always thought that part of THX certification for cinemas was to make sure that this type of equalisation was setup "within spec"."

    THX cinemas use three methods of achieving X-Curve frequency response characteristics. In old cinemas that are being upgraded, THX may design a custom screen baffle (the element which houses the left, centre and right arrays). In both new and upgraded installations, one will also find a THX crossover, the only piece of hardware actually manufactured by THX, which controls the dispersion pattern and response of the front three loudspeakers (the THX crossover is simple black box, one rack unit wide and two high, with a silver THX logo on the front).

    The third method can be applied to all cinemas, and that is to use the equalisation within the DTS, Dolby and SDDS processors. The goal is to make all cinemas sound the same and have an exact X-Curve response.

    "Maybe HCC should do a technical article on what really constitutes THX (at home and in the cinema)..."

    This is exactly what we did in the June 2000 edition of HCC (at least as far as THX in theatres is concerned), but there is certainly room for another in-depth explanation of THX in the home. I know THX PR would jump at the chance.

    "Whilst they're at it how about an explanation of Sony's dynamic whats-it (SDSSSSSS). Never see that explained."

    Sony Dynamic Digital Sound (SDDS). There's not a lot too it, the audio is delivered in the same way as Dolby Digital, on the film. Rather than between the sprocket holes, it's along either side of the print. The only major difference is the capability for an increased number of channels, namely half-left and half-right. Arguably the system is superior to both Dolby Digital and DTS, although it's a great deal more unreliable. http://www.sdds.com/


    Stuart M. Robinson
    SMR Group – http://www.smr-group.co.uk/
     
  14. Gary Palmer

    Gary Palmer
    Standard Member

    Joined:
    Jul 17, 2000
    Messages:
    328
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    16
    Ratings:
    +1
    Thanks Stuart,

    Given the above thread maybe HCC could do an article on THX for home equipment and how it applies (or does not apply) now that we are all mainly using DD & DTS.
     
  15. KAO

    KAO
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Yes, that would be a great idea. And thanks to everyone for their replies!
     

Share This Page

Loading...