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DTS track in some titles causing sub to go into distortion ?

Discussion in 'Subwoofers' started by tinytok, Dec 24, 2001.

  1. tinytok

    tinytok
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    I'm having a Rogers sub(http://www.wokeehong.com.hk/rogers/english/asb80spec.html) along with LS 330, C330 and R330.

    When playing Final Fantasy(DTS), whenever the spacecraft flies over, my sub would go bloop bloop bloop....And i've got to set the sub out at -05DB for LFE.

    What is this sympton ? Sub went into distortion when it can't takes the low fequencies ? or my sub had got something wrong ?

    Another movie would be Jurassic Park 2(DTS) when T-rex is checking out the control truck.

    Anyone experience this with other subs ? Or anyone notice the extreme low frequency that is going to the sub ?

    MY setup are as follow
    Marantz SR7200 (using mainly DTS)
    Rogers L series home theater package
    Marantz CD53 MK2
    Samsung DVD M208k
    Cabletalk 3.1 for LCR channels
    Cheap Audio sonic cables for surrounds
    Thomson True Flat 29" TV
    Some better than normal source cables
     
  2. Gary Lightfoot

    Gary Lightfoot
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    I could be wrong, but I think I read somewhere that some DTS disks have the LFE encoded at +10db.

    A reviewer discovered that when comparing DTS with DD, the DTS disc(s) sounded louder (not necessarily better) because they were encoded louder.

    I'm just wondering if that's what you're experiencing.

    I had a similar thing with my Rel - I connected the LFE to the +12db connector instead of the 0db, and that distorted and blapped terribly during Toy Story 2 opening sequence (among others).

    If +3db equates to doubling the sound, I wonder how that effected my sub, and possibly yours - if +3db equates to doubling what the subs amp is doing, then at 100w, it may be trying to amplify to 200w. +10 or +12 would definately cause the amp to go into clipping etc if this is the case.

    Gary.
     
  3. mjn

    mjn
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    3db = 100% increase in sound level.
    10db = 10 fold increase in sound level

    its all to do with logs.
     
  4. torimusic

    torimusic
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    There could be a number of reasons for this. Firstly, I assume that your sub, if it's the ASB-80 (which I checked on the web link you supplied. I'm not familiar with Rogers) then I assume you have an 8 inch driver. My past experience with subs reveals that any sub with a driver smaller than 12 inch is not going to ‘cut the ice’ in the budget subwoofer price range. My first sub was a Polkaudio PSW-50 which had an 8 inch driver. I tried the sub in various configurations and setups but in the end, I came to the conclusion that the sub itself was the weak link in my system. I then upgraded to the Velodyne CT-120 which is a 12 incher. This is a hefty sub weighing in at 25kg and it sure packs a punch. It’s quite affordable too. It has a pretty tight bass and handles everything I throw at it. It performs great with music and movies. I mainly watch movies and the sub really kicks ass considering that it still falls into the category of budget equipment. Check the range out at www.velodyne.com

    Another thing that will affect how your sub performs (and this is VERY VERY important), is the method you use to connect it to your system. Most audio-video receivers have a subwoofer output jack. You must AVOID using this jack. The best method I found that gives me the best results is as follows:

    *In your receiver’s setup, (assuming you have bass management ie: you can set your speakers to large, small, none etc.) set your subwoofer to ‘off’ or ‘none’.
    *Set your front main left/right speakers to ‘large’
    *Set the center and surrounds to ‘small’
    *These settings will ensure that any bass and LFE information will be redirected from the subwoofer output jack to the front main left/right speaker banana outputs and the front left/right line level RCA pre-out outputs (assuming your receiver has these. If not, you will have to use speaker level inputs on the sub). From the front main left/right line level pre-out RCA jacks of the receiver, connect a stereo RCA to RCA cable to the left/right line level inputs of your sub
    *If your sub only has speaker level inputs, then connect a pair of speaker cable from the left speaker output banana jacks on the receiver (in parallel with the pair going to the left speaker) to the left speaker level input on the sub. Do the same for the right channel respectively with another run of speaker cable.

    Set the sub to about just over half volume (approx 1 o’clock). You should get better results from the sub.
     
  5. Stuart Wright

    Stuart Wright
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  6. Nic Rhodes

    Nic Rhodes
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    For general advice this is rubbish, it is all down to how things are engineered. The majority of people I know use the 0.1 output and it HIGHLY successful. It is not to say this is the only method. The FAQ gives an assortment of connection methods.
     
  7. Lowrider

    Lowrider
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    Small correction:

    3 db = twice the power from the amp
    10 db = ten times the power from the amp, twice the sound level
     
  8. Reiner

    Reiner
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    I agree with Nic, for AV systems the RCA/phono connection is usually the one to use and let the AV amp handle the bass management.

    You may connect via high level as alternative and some subs even offer to connect both at the same time.
    This may make sense if you use the same system to listen to music very often.

    I also run a mixed setup but use low level connection only and normally do not use the sub for music but just for the LFE.
     

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