avalanche 18" with adire ada1200 question- please help!

Discussion in 'Home Theater Projects' started by Gary*c, Mar 6, 2005.

  1. Gary*c

    Gary*c Auditioning

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    Hello,

    I am trying to design/build my first HT sub. I have narrowed down the parameters- sealed Q=0.707, tuned to 20hz, smallest possible box, most possible output [​IMG]

    I need to make this sub as small as possible (WAF) so thats why I chose the adire ada1200 since it has a built in LT circuit. I chose the avalanche 18" since that seems like the biggest/baddest/cost effective driver out there.

    Can someone who understands the math behind LT help me out here. If I was to fully utilize the LT circuit in the ada1200, how small can I get a sealed internal volume to still be flat to 20hz for the 18" avalanche? I know without the LT, it would take roughly 6.2^3 ft. for a Q of 0.707 sealed. Unfortunately, WAF prohibits a box that large.

    Thanks in advance!
     
  2. Jason Dalton

    Jason Dalton Stunt Coordinator

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    The idea of a Linkwitz Transform is that you can make it flat to whatever frequency you want no matter how small the box is. So its really going to come down to how much output you want. The smaller the box the less output you get.

    You've selected some good equipment, if I were you I would build a sealed box that suits your requirements and play around with the settings from there. Use an SPL meter to help you get flat frequency response. You may be able to get it flat to 20Hz with the PEQ alone or you may have to utilize the LT circuit. It'll take some tweaking.
     
  3. Jason Dalton

    Jason Dalton Stunt Coordinator

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    Also consider the Avalanche 15. It works better than the 18 in a small sealed box. You will get similar output because of the reduced LF efficiency the 18 experiences if you put it in a small volume.
     
  4. David_P

    David_P Stunt Coordinator

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    Chad or someone else with experience with these drivers can chime in, but I think you'll find that the Avalanche 18 can be overdriven (xmax exceeded by an ADA-1200, particularly if the LT is used.

    Place around with the LT spreadsheet from the FRD consortium... I think you'll see the ada-600 is a better match for the driver.

    David.
     

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