MW65xx Drilling Jig

xschop
xschop Posts: 5,000
edited June 2022 in DIY, Mods & Tweaks
Started this project today. Dedicated drilling jig for the vintage MWs. Will completely encapsulate the driver and protect the butyl rubber while locating and drilling for extra holes. I went with 6.505" OD on billet top plate with a 0.500" locating hole that clears phase plugs...

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Will make holes next....

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  • Gardenstater
    Gardenstater Posts: 4,455
    edited June 2022
    So much nicer than my plan to use masking tape........when I finally get....to......it......

    Thanks!
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • F1nut
    F1nut Posts: 50,494
    Rob, I have to say...you're never short of ideas :)
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • pitdogg2
    pitdogg2 Posts: 25,412
    Watching closely. 👍
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  • BlueBirdMusic
    BlueBirdMusic Posts: 2,267
    Pretty amazing as is your mind.
    "Sometimes you have to look to the past to understand where you are going in the future"




    Harry / Marietta GA
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  • vader540is
    vader540is Posts: 190
    Fantastic work.
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  • xschop
    xschop Posts: 5,000
    Bump for @Jazzhead
    Don't take experimental gene therapies from known eugenicists.
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  • xschop
    xschop Posts: 5,000
    edited October 2022
    Drilled a couple out today. Those dimensions are good to go on 6502, 6510, 6516, and 6500 so far. Don't see why others would be different.

    I'll be setting up a large bench press at home shop area so I don't have to drive across town to do them and will offer this service in conjunction with phase-plugging if you're interested...

    g7rtupba7jem.jpg

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    Don't take experimental gene therapies from known eugenicists.
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  • xschop
    xschop Posts: 5,000
    edited October 2022
    I started using a 5/16" leather punch around new hole diameters to trim the butyl surround. Works perfect...

    k5fd7b6nu1b2.jpg

    Black permanent marker to touch up the scored area from the leather punch...


    ay34ifbb8o7u.jpg

    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,455
    Nice! Another idea I had is to try indexing the MW and PR by 45deg to see if it improves/tightens the bass response. Going on the idea that the 1st reflections are what we want to maximize and that would *perhaps* strengthen them and make them more coherent on left and right reflections off the cabinet enclosure.

    I will be doing mine soon after I solve my FWD bearing and exhaust problems on my Honda Civic.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • xschop
    xschop Posts: 5,000
    I previously tested this mod out on the 5B's and removed the steel backer rings to have a listen. Very worthwhile with just 8 hurricane nuts. The cabinet baffle itself is not as solid as having the rings, but the MW flange does NOT vibrate/resonate AT ALL. You can easily feel the vibes just having the factory 4 locations with hurricane-nuts. Bass and midrange improve greatly as well with this mod alone.
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,455
    Even with the thin and fairly soft Polk supplied gaskets you can visibly (and measurably) see that the steel basket flange bends between the 4 hole locations. The more pressure you can get between the basket flange and the baffle, the better the coupling. Obvious conclusion is that we also need the pressure to be as even as possible over the entire circumference. How could 8 screws not be better than 4 with this thin steel basket? The later models of MW are even thinner than early ones.

    All these small but noticeable incremental improvements add up to a substantial difference in listening enjoyment.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • xschop
    xschop Posts: 5,000
    Just having the 4 factory points stresses the stamped steel over time. I've observed many of the baskets and even chucked up a few in the lathe via their baseplates to discover that the steel flanges are bent/out-of-round.

    I've found the 4 extra mount points not only straightens them out, but now effectively recruits the annular raised flange to be a doubling effect for baffle stiffening alone.
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,455
    edited October 2022
    The only thing better might be to epoxy your speakers into the baffle 🤣

    But seriously, compression force on the baffle may actually help to stiffen it as well.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • xschop
    xschop Posts: 5,000
    The 5Bs have been the catch-all for for all the vintage Polk R&D. :D They are currently proving to my ears that a Dayton cap is just as good as a Clarity PX on the tweeter circuit. ;) Really struggling to hear a difference.
    Don't take experimental gene therapies from known eugenicists.
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  • xschop
    xschop Posts: 5,000
    edited April 2023
    Found another use for this jig....

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    yf2m2588pmig.jpg

    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,455
    How big of a piece of BH5 does that require?
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • xschop
    xschop Posts: 5,000
    It already sucked all the bass out.
    Don't take experimental gene therapies from known eugenicists.
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