Subwoofer question

Discussion in 'Archived Threads 2001-2004' started by David G. Lee, Nov 23, 2002.

  1. David G. Lee

    David G. Lee Auditioning

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    I has been 30 years since I last wired together some hi-hi amps and built several different speaker enclosures. I have assembled a few electronic projects (either kits or followed articles)over the years and have done a fair amount of carpentry and have all the necessary tools.

    I have decided to part with time, energy and $$$$ and put together my own powered subwoofer - however in the previous 30 years things have changed some what and I would like some clarification on a couple of things.

    If I have a powered sub with it's own say a 300 watt amp do I also need a Linkwitz Transform Circuit in sealed sub?

    Will the subwoofer output on the AV amp supply only the required low end frequencies to the sub amp or will some sort of filter be required?

    Sorry if they are dumb questions but to a 55 year old who learnt about transistors in first year Physics it's been a long time!!!
     
  2. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    You don't have to worry about either of those things. The AV receiver will supply a conditioned signal that only needs amplification.
     
  3. David...also, a linkwitz transform is only for those of us that want to try and bend physics by creating an "un natural" responce. There are plenty of sealed drivers that need no additional EQ. As long as you can accept the box size, then you are good to go.

    how low,loud, and big od a box can you have? I am sure we can recommend some good drivers for you with that 300watt amp.

    If the external 300watt amp for the sub is a monoblock or a reciever (is it 4 ohm stable?) then you will be ok at the basic level. Plate amps offer the addition of a variable phase (for better integration...though may people really don't use it right), rumble filter (you don't want this if you are going sealed), a variable XO (only needed if you want something different than the 80hz built into the reciever), and a volume control (even with a monoblock, the recievers sub-level control should be enough).

    Hope this helps
     
  4. Dustin B

    Dustin B Producer

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    To elaborate on the LT. It allows you to place a driver in a non ideal enclosure and then modify the response to match a particular Q and F3. Depending on how far you try and modify the response, the driver and the performance goals; there are minor to major drawbacks.

    Put a driver in an ideal enclosure and you don't need an LT.
     
  5. David G. Lee

    David G. Lee Auditioning

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    Thanks for those reples - they have helped a lot. I don't know where I got the idea of a sealed unit as I am looking at something along the lines of the Shiva Vented Box applications at http://www.adireaudio.com/Files/Vent...plications.PDF
    The 142.5 L enclosure on page 20.
    The amp will be the 300 watt subwoofer amp from Elliott Sound Products at http://sound.westhost.com/ Mainly because he is local (Oz) and therefore parts should not be a problem.
    I am yet to check out the local supply for the Shiva Driver but if not available locally do you think any other driver of similar/identical specs would work in the above box? Also any experience in shipping Drivers OS? how do they travel?
    David
     

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