Bracing drive units on World Design speakers

Discussion in 'DIY Discussion' started by Chris, Jul 14, 2008.

  1. Chris

    Chris

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    I am just finalising the definitive internal chipboard boxes for the World Designs WD20s prior to skinning them with 5mm mdf. I was about to glue down the tops and bottoms but suddenly had a what if moment. What if I were to brace the actual drive units against the back of the box itself and any ideas on how best to do it ? On the WD25s Peter Comeau uses an mdf rectangular brace and some sort of mastic, I think. Any other suggestions so as not to take up more internal volume than necessary ?

    Although not really necessary, according to Peter there could be a small improvement and as I have gone the whole hog making external crossovers, in for a penny .........

    Chris
     
    Last edited by a moderator: Jul 14, 2008
    Chris, Jul 14, 2008
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  2. Chris

    Dick Bowman

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    Presumably some sort of brace between bass/mid magnet and cabinet rear?

    One downside I can think of is that you'd be making a direct connection between a fairly live bit of driver and a large cabinet panel. Might be a path for unwanted vibrations to leak from the driver to the outside world.

    I think that bracing the magnets is a "good thing" - but suspect that this might not be the best way to do it (what makes sense for a manufacturer needing to make shippable boxes isn't always the best idea for the lone experimenter).

    I'd envision an alternative construction where drive units are anchored to a "mechanical ground" column, then the outer box only has to define a volume and resist air pressure rather than also dealing with mechanical driver vibrations.

    But it's a bit late now...
     
    Dick Bowman, Jul 14, 2008
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  3. Chris

    cooky1257

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    Isn't there already a pretty large connection between driver and large panel on the front baffle?
    My understanding is this lossy coupling of the rear of the driver to the internal bracing is as used in the Tannoy DMT cabinets and helps damp any motion induced MF/HF ringing in the speaker basket/frame, at the same time it is transparent to any LF vibrations so they can dissipate through the bracing/cab walls.
     
    cooky1257, Jul 15, 2008
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  4. Chris

    Chris

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    Just remembered the PVC tubing used to double up as a port/brace in my old HB2s. What say I cut some rigid, say 5 cm diam (so as not to foul the magnet breather hole and 7mm section tubing just to undersize against the back wall of the box and literally perforate said tube with lots of 12mm holes widthwise to form a sort of machinegun silencer lookalike wotsit and then some assembly glue against the back wall and something squidgy against the back of the driver. Sound OK ?
     
    Chris, Jul 18, 2008
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