I need a 6 db boost for sub, help

Discussion in 'Archived Threads 2001-2004' started by Ryan T, Jan 23, 2002.

  1. Ryan T

    Ryan T Second Unit

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    Hi,

    I'm going to get my tempest really soon hopefully I can order it this week. I've been looking over the frequeincy response of the tempest in 260 L sealed box and it has an F3 of about 36 Hz. I would like to get the F3 down to under 20 Hz if thats posible. I've been playing around with the EQ in lspCAD and if I boost 20 Hz 5.5 to 6 bd I can get an F3 of about 19 Hz. Is there anyway to make a booster of some sort? Also since my room is small (10'x14'x8') what type of boosting will I get from my room?

    Ryan
     
  2. Kyle Richardson

    Kyle Richardson Screenwriter

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    There are several single channel equalizers on the market that will let you boost 20Hz. There are also parametric equalizers out there that will let you boost the frequency that you choose.

    Just be sure you have the amplifer to back it up. As you boost frequencies the demand on the amp increases greatly!

    -------------------

    Kyle Richardson

    Acoustic Visions
     
  3. NathanP

    NathanP Supporting Actor

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    Hey, you know what?

    I bet you can find a cheap (or somewhat cheap) 31 band eq on Ebay that'll have a boost for 20 hertz.

    Nathan
     
  4. Michael R Price

    Michael R Price Screenwriter

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    I don't think you'd want to add a bass boost to that sub. Unless you have a very large room, the natural gain from the room will counteract the slow rolloff of the sealed sub, probably down to the 18-22Hz range. In your room it should be fine. If you added a boost, you might end up with more than you bargained for. Plus the EQ would suck up amplifier power and increase group delay (might make it a bit boomier)... I'd finish up the sub without any EQ and see how it sounds/measures before trying to add anything.
     
  5. jeff lam

    jeff lam Screenwriter

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    Isn't 260L a bit large for a sealed enclosure? Thats over 9ft^3. I always thought that sealed enclosures were smaller than ported. The tempest sub I am planning will only be 175L and is ported.
     
  6. Ryan T

    Ryan T Second Unit

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    Jeff,
    I'm useing a reference design on adire audio's web page
    http://www.adireaudio.com/Files/Seal...plications.PDF
    "The low Q design for Tempest (Q= 0.577) is a traditional Bessel alignment. This alignment provides the flattest group delay curve, while still providing a bit
    more flat bass extension over a critically damped alignment. Overall, the sonic character of this alignment is of neutral, natural bass, with very good extension
    and SPL capability. This alignment is well suited for all kinds of music, but excels at reproduction of acoustic bass signals (such as from acoustic string basses,
    cellos, tympanis, and organs)."
    I listen to mostly Jazz and Contemporary Christian music so this sub seems to fit well with the type of music I listen to. I also want a sub that has good extension for movies so I choose this box. I'm really looking forward to getting my Tempest soon. Right now I'm just waiting for Adire to setup my account to order it. I figure that I should have it built within two weeks[​IMG]. I think I will just see how it sounds without hte boost first like you guys said. Thanks for the help.
    Ryan
     
  7. Pete Mazz

    Pete Mazz Supporting Actor

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    I'm getting an F3 of ~27 Hz for a Tempest in 260 l enclosure. As was said, with room gain, 20 Hz should be close to flat.

    Pete
     
  8. Richard Greene

    Richard Greene Stunt Coordinator

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    Adire recommends 230 liter enclosure stuffed with 4 lbs.
    polyfill that should "increase" enclosure size by about 14% (see attached article) 230 x 1.14 = 262 liters
    I use my Tempest in a 230 liter enclosure stuffed with
    6.5 lbs polyfill that should "increase" enclosure size by about 27% (see attached article) 230 x 1.27 = 292 liters
    My sealed Tempest tube sub is used in a large room and requires a 6dB boost in the 1/3 octave centered at 25Hz.
    In a small 150 square foot room the sub did not require any
    bass boost -- room gain compensated for the bass roll-off below 30Hz.
    http://integra.cyberglobe.net/caraud...ces/fiberfill/
     
  9. Ryan T

    Ryan T Second Unit

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    Richard,
    I don't know how I got 260L instead of 230L my bad. I've been looking at the two plate amps the PE 250 watt one and the Adire audio and i'm not sure what one is better. It looks like the AVA250 has 2 db S/N higer than the PE amp if that means anything, the AVA250 also has a .1% THD advantage over the PE amp. Is the AVA250 worth the extra money? i'm also looking into getting a power amp like this one...
    http://www.partsexpress.com/pe/showd...ID=15991&DID=7
    I would like to run the Tempest at 4 ohms. Any other amp suggestions would be appreciated.
    Ryan
     

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