THX Ultra 2 Sub setting with single Ultra

Discussion in 'Archived Threads 2001-2004' started by Doug_Z, Jan 18, 2003.

  1. Doug_Z

    Doug_Z Agent

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    I have an SVS Ultra sub. It is rated form 15-100Hz +/-3dB. The driver is about as close as you can get to being bullet proof.The spl at 20 Hz is about 112. The sub has no filter.
    No one seems to know much about the s/w settings on Ultra2 receivers. This is not an Ultra 2 sub but obviously meets the performance demands.
    Do I switch the s/w ultra sub to yes or no? If I set it to No does that prevent the full range lfe signal from being sent to the sub? If I set it to No does that activate the bass peak level limiter which I do not want?
    Finally, If I select boundary gain compensation "Yes" does that merely "attenuate" the frequency below 30Hz as Svs thinks (but is not sure) or does it roll off the frequency below 55 hz which is what I read elsewhere?
    Thank you for your time. If you don't have time to answer the question does someone have a link that may help me. I would think more people would be able to answer these questions since Ultra 2 receivers are becoming much more common. I want to get the most out of my Ultra and don't really understand why the Sub needs to be Ultra 2 certified in order to select s/w Ultra 2 "yes". I also don't know why it's so hard to find out what selecting Boundary gain compensation ON actually does? Does it attenuate the signal or cut it and at what Hz? [​IMG]
     
  2. John F. Palacio

    John F. Palacio Supporting Actor

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    Wow! I am "bumping this" because I am totally surprised NO ONE has at least the answer to one of the questions stated here. And these are most interesting questions.
     
  3. DanSt

    DanSt Stunt Coordinator

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    I to am very surprised no one has responded. I would give an answer but I don't know. I have an SVS 20-39PC and the Pioneer 49tx and also wondered about the THX sub thing too. Someone out there please reply.
     
  4. Doug_Z

    Doug_Z Agent

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    Thanks John and Dan: I am also surprised that no one seems able to answer these questions. I know many people on this forum have SVS subs, and other Subs, that are more than capable of meeting THX Ultra 2 specs (+/- 3dB @20Hz). I also know that many own THX Ultra 2 certified receivers or Pre/Pro's. So what are these HTphiles doing with these THX Ultra 2 Sub settings? It's hard for me to beleive that the people on this forum and others don't at least experiment with these settings. I would be interested if most choose s/w Ultra 2 "yes" or no? Then BGC "on" or "off"?
    I know someone who has the equipment could easily measure the subs response with the Ultra 2 setting to yes vs No. The same would be true with how the Boundary Gain Compensation ON affects the subs performance. The default setting is s/w Ultra 2 NO. It appears that in this default mode a full signal down to 20Hz and below is not output by the receiver to the sub?
    SVS has been a great help to me in buying and setting up my Ultra. IMO their service and subs can't be beat(especially for the price). However they also were no sure what selecting s/w ultra 2 "Yes" does. Or what ignoring it does? They seem to think BGC "attenuates" the signal slightly at 30 Hz or below. If that's all it does that would be fine. Others, however, have told me BGC cuts or rolls off the signal at 55 Hz. That is more of a problem as far as I am concerned.
    I know I should just experiment and decide what sounds best in my room. However, I would still like to know exactly(technically) what these settings do to my SVS Sub performance.[​IMG]
     
  5. John F. Palacio

    John F. Palacio Supporting Actor

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  6. John H

    John H Second Unit

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    My HGS-18 subwoofers frequency response measures the same whether I select yes or no under THX Ultra2 Subwoofer Setup
    If you select Yes in the THX Ultra2 Subwoofer Setup the Bass Peak Level limiter is disabled.
    However if no values are entered in the Bass Peak Levelsetup no LFE channel limiting is applied either.
    John
     
  7. Doug_Z

    Doug_Z Agent

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    Thanks.The other reason I posted this question is because my receiver's manual says If these settings are used with a sub that is NOT THX Ultra 2 certified then "this feature will not operate correctly and it's operation will be unpredicable". Will be unpredicable? What does that mean and why would the sub need to be Ultra 2 certified?

    Does an Ultra 2 certified sub have circuity or something else special that would allow it to function predicably with these Ultra 2 settings? This would suggest that non Ultra 2 certified subs would lack this circuitry and the S/W Ultra 2 setting should always be set to NO,inspite of performance specs.

    Of course it could just be a marketing gimmic to get someone to buy Ultra 2 certified subs instead of SVS,HSU etc. But that's an easy out.
     

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