Armacell Foam Inside SDA Speaker Baskets - My Experience

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  • xschop
    xschop Posts: 5,467
    edited March 2022
    This party has just started lol. I don't let the Mitutoyos leave the shop. Thanks for being thorough, Ray.
    Don't take experimental gene therapies from known eugenicists.
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  • xschop
    xschop Posts: 5,467
    Gardenstater wrote: »
    The cat has been out of the bag for a long long time with the higher end driver manufacturers! I posted this in my Foam Mod thread but I'll put it here too for some comments hopefully, where it got none before:

    SEAS Prestige Titan H1869-08 / L16RNX3 6" Aluminum Cone Woofer

    L16RNX3 is a High Fidelity woofer with an injection moulded metal chassis, intended for bass reflex and closed box designs.

    Optimized cone design combined with the stiff and light weight aluminium gives a high break-up point to allow for easier crossover design and wider bandwith than common aluminium cones.

    Titanium voice coil former with a very long copper coil winding and a bumped back-plate for excellent force transfer, transient sound reproduction and large linear excursion.

    A heavy copper ring below the T-shaped pole piece reduces non linear and modulation distortion.

    Extremely stiff and stable injection moulded metal basket keeps the critical components in perfect alignment. Large windows in the basket both above and below the spider reduce sound reflection, air flow noise and cavity resonance to a minimum.


    https://www.madisoundspeakerstore.com/approx-6-7-woofers-seas/seas-prestige-l16rnx3-6-aluminum-cone-woofer-h1869-8-ohm/

    rds3916hyapb.png

    @xschop you can clearly see how they deliberately removed the electrical connection tabs from the reflection zone so, as you know, you were on the right track with that......

    About to revisit these mods again. Contemplating doing a copper shorting ring on the pole-piece in lieu of alloy focus rings.
    Question is, should I make the copper ring only the length of voice coil travel, or the full length of the pole-piece?
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,811
    Looking forward to this one! I think the way Seas did the copper shorting ring, there was no copper in the gap, and the shorting ring was underneath. They have a patent which I'd have to see if I can find it again....

    "A heavy copper ring below the T-shaped pole piece reduces non linear and modulation distortion."
    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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  • VR3
    VR3 Posts: 29,573
    Those drivers make a crazy noise when they bottom out, not that I've ever done that
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • xschop
    xschop Posts: 5,467
    edited May 4
    Listening to the bone-stock CRS+ this weekend, I cranked them very loud and could see the rocking of the 6510's and especially the 6511's during bass passages. Threw in a plugged and focus-ringed 6502 (SDA slot) and 6516 (stereo slot).

    Dead centered linear travel at max volume.

    The focus rings are easy to install/implement. Just want to try the copper shorting ring method this go round.
    Post edited by xschop on
    Don't take experimental gene therapies from known eugenicists.
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  • xschop
    xschop Posts: 5,467
    The game plan is to machine the pole-pieces to 0.885". (The ID of a 3/4" copper coupler) and slip-fit. It just happens to have an OD of 0.985" (factory PP is 0.990")...which will give the sloppy 6510/6511 suspensions a touch more clearance to boot....

    tjuya94sclrr.jpg
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,811
    How much will that increase the gap, which will decrease BxL?
    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: 5,467
    edited May 4
    Only 0.005" gap increase, unless we include copper thickness, which is avg. 0.045".
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,811
    Yeah I meant the ferromagnetic pole gap. That's what is going to matter afaik, for the field strength.
    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: 5,467
    OK. So reason why Seas only applied copper on PP below base plate plane?
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,811
    Yeah and I think it is why they use thin plating of copper or silver (even better) when they try to put the shorting ring effect right in the gap. Must've been what the unicorn early Polk midwoofer did.
    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: 5,467
    edited May 4
    For brevity's sake, the solution is to either copper plate the entire T-Yoke, or machine the PP stem below Baseplate plane and slit the copper sleeve, then install under baseplate plane?
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,811
    Good question. Would slitting work, electrically? Would you solder it? I found the patent I was thinking of. Not Seas; ScanSpeak

    https://worldwide.espacenet.com/patent/search/family/026068168/publication/US5815587A?q=pn=US5815587A
    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: 5,467
    edited May 4
    It could easily be fluxed on or use Red Loctite.

    Looking into at home copper plating kit too. Copper Sulfate is cheap.
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,811
    What about if you turned down the pole piece on the diameter and machined a shoulder at the end to press on an annular disc/donut of 1005 low carbon alloy to form the "T"?
    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: 5,467
    That's doable.
    Don't take experimental gene therapies from known eugenicists.
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  • Viking64
    Viking64 Posts: 7,653
    pole piece = stripper
    xschop wrote: »
    That's doable.

    Yes, preferably.
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  • xschop
    xschop Posts: 5,467
    Electroplating would be much easier if it accomplishes same goal. Pugmaster is inluvwidastrippa...

    https://m.youtube.com/watch?v=PvPpcJ3ybIs&list=RDPvPpcJ3ybIs&start_radio=1&pp=ygUcaW4gbG92ZSB3aXRoIGEgc3RyaXBwZXIgc29uZ6AHAQ%3D%3D
    Don't take experimental gene therapies from known eugenicists.
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