Is this any good?Please help!!!

Discussion in 'Home Theater Projects' started by Riaad, Aug 18, 2003.

  1. Riaad

    Riaad Agent

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    I am looking to build a hometheater sub. There is not much available to me unless I order from abroad and that works out very expensive. I have come across a Diy Sub kit locally.
    The only specs that I have are
    12"
    Fs 22Hz
    Vas 120L
    Qts 0.50
    RMS 250W
    Xmax - 8mm

    100 watt plate amp with built in crossover.Will look upgrade later.
    100W Amplifier

    Output 70W RMS at 1% distortion
    100W Max at 10% distortion
    Load 4 - 8 ohm

    Both amplifiers are panel mount with an electronic crossover. The features are as follows:
    Volume control
    Phase switch
    Variable cut off frequency
    High and low level inputs

    Will this be suitable.?
    I have tried using winisd . The software suggests that this would be more suited for a sealed encloser. The kit however comes with a 4 inch port as well.

    Any suggestions on what frequency I can expect and what volume box I am looking at.?

    The kit costs about R800 ie .$107.

    Riaad
     
  2. Jack Gilvey

    Jack Gilvey Producer

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    Looks like it's best suited to a sealed box of fairly good size, maybe 4ft^3 or so to keep Qtc below .7. In such a box, with an Fc of 32Hz, you'd probably be flat to the low 20's in-room.
    Tough to get a flat response ported without a very large box, but 5ft^3 tuned to 20Hz with that 4" port doesn't look too bad. Can't tell if the 8mm Xmax is one way or peak-to-peak, but either indicates limited SPL compared to a Shiva or the like. The amp seems well-suited, I'd probably go with what the kit maker recommends.
     
  3. Riaad

    Riaad Agent

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    Hi

    Im not sure. If using winisd, and selecting a sealed box, do you take the F value at -3.Like you mentioned the FC value is only 32hz. Is this not a bit high.How would it go to the lower 20's.Is it room gain? Please excuse me , im new to this.

    What other specs would be benificial in detremining if this
    driver will be any good other then the ones given?

    I am a bit hesitant as like you see it requires a fairly large box.I have a small room 11x12 feet.Not sure if there is space for such a box .

    Thanks
    Riaad
     
  4. Jack Gilvey

    Jack Gilvey Producer

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  5. Riaad

    Riaad Agent

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    Hi

    The x max is one way.
    One other thing .Is there a way to work out the volume for the internal bracing. Also if I go for the but 5ft^3 tuned to 20Hz with that 4" port.The port length needs to be 34.73cm. is this correct.Is this too long?
    Will using some polyfill also help?


    Thanks
    Riaad
     

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