3802 + Sub

Discussion in 'Archived Threads 2001-2004' started by Earl Simpson, Jun 28, 2002.

  1. Earl Simpson

    Earl Simpson Supporting Actor

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    I have a question? Since my sub is a little boomy at 80 htz and I have main + sub set, why can't I set my sub crossover to 50 htz? All of the bass should be duplicated by the mains or am I missing an important detail?
     
  2. Bill_D

    Bill_D Supporting Actor

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    From the Denon manual:

     
  3. EricK

    EricK Second Unit

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    Earl,

    What db is your sub calibrated at? Your Sub should be calibrated at 79db spl...speakers 75db spl.

    Also you may want to consider turning down the overall vomume on your sub and adjusting it through the 3802.

    Eric.
     
  4. Dustin B

    Dustin B Producer

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    Eric, why should your sub be 4dB above your mains?
     
  5. EricK

    EricK Second Unit

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    Dustin,
    There was a huge debate on here a while ago about how to calibrate the sub for the home system. Some people were setting their sub +10db spl and some -10db spl.
    After having read an article in Surround Professional, I was certain that neither -10db or +10db were correct. I was right. According to Surround Professional, the sub should be calibrated to +4db spl above the 5 main speakers.
    Here is the link and an excerpt from the article...
    http://www.surroundassociates.com/spkrcal.html
     
  6. Dustin B

    Dustin B Producer

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    Have you read this?
    http://www.hometheaterhifi.com/volum...pril-2000.html
    What you calibrate to depends on what you are using for tones and your personal preference for bass. VE requires you to set your speakers to 75dB and the sub to 85dB to be at reference levels. Avia on the other had requires you to set your speakers and sub to both 85dB. With internal receiver or processor test tones only God knows what you are actually getting.
    However, Avia notes, and I agree that reference level is too loud. I mostly watch at 10dB under reference and give demos at 5dB under reference (although my sub is 2-3dB hot).
     
  7. Earl Simpson

    Earl Simpson Supporting Actor

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    OK, So I use a calibration disk to see if I can set my sub at 50htz for a crossover and not have any dead spots in the audio spectrum. The 3802 has only a 80 htz internal crossover and I need to avoid that area of the audio spectrum for my sub(70 - 80 it is way too efficient).
    I just wanted to know if anyone had tried setting the sub+main and large for the front speakers and 80 htz for the 3802 internal crossover and their sub set at 50 htz?
     
  8. EricK

    EricK Second Unit

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    Dustin

    I have checked out the article, and it does not do much to straighten any of the issues out. All the article really does is explain how the LFE is concieved from mixing room to the home theater.

    What I did see the article say was that the LFE should be at the same level as the mains...


    Why? What is wrong with using the test tones of the receiver or processor? That should be the MOST accurate way of calibration.

    Eric.
     
  9. Nick P

    Nick P Second Unit

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  10. Richard_M

    Richard_M Second Unit

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    Hi Earl,

    I am not sure how the 3802 goes with LFE set to both mains & sub. I used to use this feature with my Yamaha amp and loved the bass boost. When I upgraded to the Denon I also got a BFD equaliser. Since setting up my system I have all speakers set to small, & LFE out to my dual subs.

    Maybe you should try to take the peak out of the sub using an equaliser instead of complicating the bass and also the possibility of duplicating the affected freq range.

    The other issue here is the possibility of overdriving the amp as it will then have to produce the bass for the mains. this may or may not be a problem depending on how efficient your mains are and also their impedance, and of course how loud you like to listen.

    BTW I also have mine amp Xover at 80hz and subs Xover bypassed.

    Regards,
     
  11. BrianWoerndle

    BrianWoerndle Supporting Actor

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    It all depends on what you are calibrating with.
    I read an article on the definition of reference level (Too bad I don't remember where I saw it). In the definiton of reference, the mains were to be 85db, which allows for peaks at 105db. The sub was to be 95db, with peaks at 115db. Reference for a sub is defined at 10 db higher.
    Test discs like Avia or VE know this and design their test signals for the sub to be 10db higher so the user only has to calibrate to 1 level. If you are using raw test material you would have to adjust accordingly. But using raw material is hard because you have very little control of the level of the signals. A test disc like Avia or VE have signals that are much more accurate.
     
  12. EricK

    EricK Second Unit

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  13. Dustin B

    Dustin B Producer

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    Eric, are you talking about level matching speakers or calibrating to reference or near reference level? They are two very different things and internal test tones are a very bad choice for the second, but ok for the first.

    I personally want my speakers level matched and want to know where they are relative to reference level. To do this you cannot use the internal test tones, you must use a proper calibration disc.

    Using a calibration disc and setting to reference level the very last thing you want to do is set your sub 4dB hot. There are so few subs out there that can actually do this level (in fact there are very few inexpensive to moderately priced that can actually do 10dB below reference cleanly). As noted above reference level requires peaks of 105dB from the speakers and 115dB from the sub at the listening position, assuming none of your speakers are set to small (that article I linked to explains why the LFE channel is set 10dB above the rest of the channels). As soon as you set all your speakers to small (which is 95% of the time the best thing to do with a home theater setup) the sub is now required to produce peaks of 121dB at the listening position. Even dual SVS Ultra's in a medium to larger room would have trouble doing this. You run them 4dB hot and only some elaborate multidriver DIY designs could do it.

    I should have kept my mouth shut on VE as I've never used it. I don't know if it's sub level tone is set so that you calibrate to the same level as the speaker or not. But with Avia I know it is. To calibrate to reference level you DO NOT SET THE SUB 4dB ABOVE THE REST OF THE SPEAKERS. Using Avia you level match everything to 85dB and you are at reference level. Or to some lower level if you find that two loud. Personally I use 75dB.

    Now some other discs may require you to calibrate the sub 10dB above the other speakers. None will require you to do 4dB above the other speakers. Setting the sub 1,2,3,4,5,6dB above the other speakers is something you only do because of personal preference. I personally like to watch movies at 10dB below reference with my sub 2-3dB hot.
     

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