Subwoofer SPL levels and THX optimizer

Discussion in 'Subwoofers' started by Philip Newton, Aug 13, 2002.

  1. Philip Newton

    Philip Newton
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    Ok I have read many past posts about the setting of speakers with the spl meters but could not work out what was the best way of setting up the system. Firstly I was wondering if I use the test tones on my amp (sony 475) do I set the sub the same as the speakers e.g 75db. I read that the spl meters are not that good at low levels, and I saw that there are some adjustments you can make. In the FAQ it says to set sub at 85db has an adjustment already been made for this etc. Secondly is it better to use THX optimizer and what setting should I use e.g. does it adjust for the sub aswell. A simple answer must be available.
     
  2. bob007

    bob007
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    Set all speakers to 75db thats including the sub, then you can adjust the bass from there, 75db is a good starting point, you can then increase/decrease the bass from there..

    Test discs include a tone for the sub.
     
  3. Electric Mayhem

    Electric Mayhem
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    Hi

    If you use the test tones of the amp set all channels to 75db inc. the sub. If you want, you can set the sub channel to whatever suits you, some people have it set lower, others higher, it´s down to personal taste.

    For more accurate balancing use a test disc such as AVIA or Video Essentials.

    AVIA

    Video Essentials

    If you use AVIA set the channels to 85db, for Video Essentials set to 75db.
     
  4. Philip Newton

    Philip Newton
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    is it better to set the volume on the sub itself lower and use the amp to tune it to 75db or the other way round, it is set at 12 o clock on the sub itself crossover at 150 and the bass is realy nice on some discs but on others it is so loud that it causes the problem I described in my other post. I thought I could fix this by setting it below 75db but don't want to move away too much from refrence level. thanks again I am grateful of your responses, one day i will be wise enough to help you guys.
     
  5. Electric Mayhem

    Electric Mayhem
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    I tend to set the volume on the sub to around a third, half way and adjust via the amp.
     
  6. bob007

    bob007
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    What speakers have you got? Are they satellites?

    150Hz crossover seems a bit high if they are not.
     
  7. Electric Mayhem

    Electric Mayhem
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    Also depends how you have them configured, Large/Small etc Bass to both etc etc
     
  8. Philip Newton

    Philip Newton
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    all set to small with mission cinema 6 all 5 are ok just probs with intrusive bass
     
  9. bob007

    bob007
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    The frequency on the satellites are rated at 85Hz for Mission Cinema 6, try turning down the crossover on the sub to 90Hz/95Hz and setting the sub at 75db again.
     
  10. Ian J

    Ian J
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    150 Hz is too high. Try 100Hz or a bit lower if possible as the main speakers can normally handle these frequencies better than the sub. Also bass is only non directional at low frequencies and you can probably hear where the bass is coming from.

    I find the test tones useless for setting the sub and do it by ear.
     
  11. Philip Newton

    Philip Newton
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    you guys sure do know your stuff!! will try it tonight, I doubt my ears are able to set the sub so will rely on spl for time being, do you think this will reduce the problem i have with over working the sub?
     
  12. bob007

    bob007
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    Yes, you have too much mid range going through the sub.
     
  13. Philip Newton

    Philip Newton
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    silly question but my crossover goes from 50 to 150. in terms of position e.g. 12 o clock what time should my dial be at for 90/95 hz cheers as it is hard to tell as it is not graded
     
  14. Ian J

    Ian J
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    It's fairly easy. Turn up the volume on the sub until you can just hear it then turn it down a bit and possibly a bit more as well. It will take a while to get it right.
     
  15. bob007

    bob007
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    Try 12o'clock, you can check your crossover if you have a dvd with THX optimiser on it, this has a frequecy sweep on it, if not rent Cast Away or Star Wars think these have it on. Run the sweep this will tell you if you have got the crossover about right, if there is a gap in the sweep then turn the crossover up.
     
  16. Philip Newton

    Philip Newton
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    cheers will try it have 2 or 3 discs with it on will let you know if it works
     
  17. Philip Newton

    Philip Newton
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    NICE ONE!!, T2 Sounded ace gun shots and with a sense of presence not just a rumble in the corner. However still have major vibrations on certain scenes. I have asked in another post but does stuffing something in the reflex port to reduce vibrations damage the sub or kill the sound. If you cant help do you know contact for mission and I will ask them
     
  18. Electric Mayhem

    Electric Mayhem
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  19. Philip Newton

    Philip Newton
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    Superb service at mission totally superb! they are seding out a special bung to sort the problem FREE of charge and want me to call them back with feedback. Hope it works
     
  20. Philip Newton

    Philip Newton
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    Sorry to bring this thread back to life but am wondering now that I have upgraded by amp to denon 2802. I have the amp crossover set to 80hz and crossover on the sub set to max, it says above my speakers can handle up to 85hz so should I set the amp crossover to 100hz to get a better effect and still leave sub crossover set to max Thanks in advance. By the way mission has to repair my sub in the end due to faulty amp inside now works a treat!!
     
  21. Electric Mayhem

    Electric Mayhem
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    Only thing to do is to try it, see which sounds best to you. I´d personally leave it at 80hz and have a slight gap rather than ask the sub to produce bass higher up the frequency.
     

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