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Thread: Speaker Box Suggestions Request

  1. #41
    Join Date: Nov 2014

    Location: Leicestershire

    Posts: 180
    I'm Mark.

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    Quote Originally Posted by walpurgis View Post
    Right.

    Done a bit of research and working out. The cabinet volume is just under 18 litre. Taking the bass driver resonance as 60 Hz, it may be wise to tune the port slightly below that to avoid the box resonance overlapping that too much and creating larger than desirable 'hump' (there wiil be a slight one), so I'd aim for 50Hz, that will also allow the bass to extend down a bit further, there will certainly be sufficient output from the driver at that frequency to excite the reflex action. This will require a tubular bass port of 6 inches length and 2 inches inside diameter. There will be roll off below 50 Hz, but you should still get some output at 40Hz, maybe even lower if you're lucky.

    I use usually use cheap plastic waste piping from places like B&Q for ports, but as Grant says, there are custom ports available that can be adjusted for length, allowing cabinet tuning to be played with.
    Thank you for the effort!
    I won't have 6" front to back - the box is 7" deep outside, minus 2 3/4" only leaves 5 1/2" inside. How much gap to the inside of the back is required?
    Could I run the pipe in at an angle?
    Should I still use wadding?
    Thanks for your knowledge!

    Sent from my LG-H850 using Tapatalk

  2. #42
    Join Date: Apr 2012

    Location: Southall, West London

    Posts: 36,235
    I'm Geoff.

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    The port can go anywhere, as long as the internal end is not right by the back of the driver. It does not need to be at the front, you can bung it in the side if that suits.

    Yes, you still use wadding, but probably less and around the walls of the cabinet leaving space in the middle. You can experiment with quantity.

  3. #43
    Join Date: Apr 2012

    Location: Southall, West London

    Posts: 36,235
    I'm Geoff.

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    You can if need be try a slightly shorter port and part plug it with rolled resistive open cell foam. This effectively makes the port narrower, but retains the bass tuning.

    This kind of stuff: https://www.ebay.co.uk/itm/ACTIVATED...1GSjecLSvo5V3Q You may find it cheaper elsewhere.

    It would be trial and error though. i.e., how much to shorten the port and how tight to pack the foam. Obviously not so tight as to stop air movement.

    Hope your ears are good enough to judge what goes on!

  4. #44
    Join Date: Nov 2014

    Location: Leicestershire

    Posts: 180
    I'm Mark.

    Default

    Quote Originally Posted by walpurgis View Post
    You can if need be try a slightly shorter port and part plug it with rolled resistive open cell foam. This effectively makes the port narrower, but retains the bass tuning.

    This kind of stuff: https://www.ebay.co.uk/itm/ACTIVATED...1GSjecLSvo5V3Q You may find it cheaper elsewhere.

    It would be trial and error though. i.e., how much to shorten the port and how tight to pack the foam. Obviously not so tight as to stop air movement.

    Hope your ears are good enough to judge what goes on!
    Ha!
    My ears aren't what they once were!
    Thanks for all the great advice!

    Sent from my LG-H850 using Tapatalk

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