Phase Plug design for MW65xx

2

Comments

  • xschop
    xschop Posts: 2,022
    edited March 2020
    Faustin wrote: »
    Nice work. When do you start full blown production? B)

    As soon as someone with a set of 2B's or CRS wants to experiment.

    Post edited by xschop on
  • xschop
    xschop Posts: 2,022
    Mick Hucknall now added to the clean-up list.
    His "Sad 'ol Red" is hauntingly present.
  • skrol
    skrol Posts: 3,033
    I'm curious... By removing the dust cap, doesn't it allow more air leakage in an otherwise sealed cabinet? I realize that there is normally a small amount of leakage.
    Stan

    Main 2ch:
    Polk LSi15 (DB840 upgrade), Parasound: P/LD-1100, HCA-1000A; Denon: DVD-2910, DRM-800A; Monster HTS3600-MKII, Grado SR-225i; Technics SL-J2, Parasound PPH-100.

    HT:
    Marantz SR7010, Polk: RTA11TL (RDO198-1, XO and Damping Upgrades), S4, CS250, PSW110 , Marantz UD5005, Pioneer PL-530, Panasonic TC-P42S60

    Other stuff:
    Denon: DRA-835R, AVR-888, DCD-660, DRM-700A, DRR-780; Polk: S8, Monitor 5A, 5B, TSi100, RM7, PSW10 (DXi104 upgrade); Pioneer: CT-6R; Onkyo CP-1046F; Ortofon OM5E, Marantz: PM5004, CD5004, CDR-615; Parasound C/PT-600, HCA-800ii, Sony CDP-650ESD, Technics SA 5070, B&W DM601
  • pitdogg2
    pitdogg2 Posts: 18,539
    skrol wrote: »
    I'm curious... By removing the dust cap, doesn't it allow more air leakage in an otherwise sealed cabinet? I realize that there is normally a small amount of leakage.

    My thoughts exactly.
  • xschop
    xschop Posts: 2,022
    skrol wrote: »
    I'm curious... By removing the dust cap, doesn't it allow more air leakage in an otherwise sealed cabinet? I realize that there is normally a small amount of leakage.

    Great question. I initially thought that also, until I realized it was very porous woven cloth from the factory. I could shine a light through the dust cover and see the pole piece itself. Once removed, you can freely blow air through the cover. And lasty, nothing changed doing the PR push test from before.
  • mhardy6647
    mhardy6647 Posts: 27,329
    xschop wrote: »
    Add Donald Fagan to the list.

    Aluminum-y Dan?

    ;)


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  • xschop
    xschop Posts: 2,022
    mhardy6647 wrote: »
    xschop wrote: »
    Add Donald Fagan to the list.

    Aluminum-y Dan?

    ;)


    cxm1u9t24nbw.jpg

    Better than Tinny Dan in this case.
  • mhardy6647
    mhardy6647 Posts: 27,329
    xschop wrote: »
    mhardy6647 wrote: »
    xschop wrote: »
    Add Donald Fagan to the list.

    Aluminum-y Dan?

    ;)


    cxm1u9t24nbw.jpg

    Better than Tinny Dan in this case.

    or Tiny Dan I suppose.

    :|
  • xschop
    xschop Posts: 2,022
    mhardy6647 wrote: »
    xschop wrote: »
    mhardy6647 wrote: »
    xschop wrote: »
    Add Donald Fagan to the list.

    Aluminum-y Dan?

    ;)


    cxm1u9t24nbw.jpg

    Better than Tinny Dan in this case.

    or Tiny Dan I suppose.

    :|

    Dare I say.... the mod cleans up Barry White's voice.
  • JayCee
    JayCee Posts: 1,176
    edited March 2020
    Finished reading through this thread earlier in the afternoon. Just now, looked up at the demo pair of L200's I'm listening to and what do you know. Light hit them just right and I noticed the dustcap....is pointed. Hmmmm..........

    *Edit to add...delicate probe with my digit and it's defiantly not a soft dust cover and gives a bit w/slight pressure. I assume there's a very tight weave to the design. Tried to shine a flashlight into it and can't see anything pass through. Pulled out the green "LAZER" and it doesn't reflect or illuminate anything.

    **DISCLAIMER: NO DUST CAPS WERE HURT IN THE MAKING OF THIS POST. :neutral:

    n8yp2u18dwf4.jpg
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    Speakers: Polk1.2tl's (Uber Mods) Pre/Amp/DAC: PS Audio BHK Signature & 250, DirectStream Cables/IC's: MIT S1Bi-Wire/S1 Balanced +Avel Lindberg 1000VA "Dreadnought" Power Conditioner: PS Audio P15 Power Plant Power Cords: Core Power Technologies Gold, DH Labs Power Plus DIY w/Neotech NC-P301 & P311ends Streamer: Roon ROCK on wifi'd NUC & Uptone EtherREGEN⟿Ω☯☥☮⟿🔊♩♪♫♬♩♪♫♬♩♪♫♬
  • xschop
    xschop Posts: 2,022
    Is it fixed to the pole-piece or part of the cone diaphragm?
  • JayCee
    JayCee Posts: 1,176
    It's part of the diaphragm. Would imagine there's a point (pun intended) to it. Might be worth a PM to Stu to see if he'd give you some insight on the current design.
    Speakers: Polk1.2tl's (Uber Mods) Pre/Amp/DAC: PS Audio BHK Signature & 250, DirectStream Cables/IC's: MIT S1Bi-Wire/S1 Balanced +Avel Lindberg 1000VA "Dreadnought" Power Conditioner: PS Audio P15 Power Plant Power Cords: Core Power Technologies Gold, DH Labs Power Plus DIY w/Neotech NC-P301 & P311ends Streamer: Roon ROCK on wifi'd NUC & Uptone EtherREGEN⟿Ω☯☥☮⟿🔊♩♪♫♬♩♪♫♬♩♪♫♬
  • JayCee
    JayCee Posts: 1,176
    edited March 2020
    I might add, and nothing to do with your thread, I really like these L200's. Shout out to the newest Polks! BIG SOUND for the small size. Very detailed and really shine on my best gear. Said too much. Detailed thoughts will be in my review. <3
    Post edited by JayCee on
    Speakers: Polk1.2tl's (Uber Mods) Pre/Amp/DAC: PS Audio BHK Signature & 250, DirectStream Cables/IC's: MIT S1Bi-Wire/S1 Balanced +Avel Lindberg 1000VA "Dreadnought" Power Conditioner: PS Audio P15 Power Plant Power Cords: Core Power Technologies Gold, DH Labs Power Plus DIY w/Neotech NC-P301 & P311ends Streamer: Roon ROCK on wifi'd NUC & Uptone EtherREGEN⟿Ω☯☥☮⟿🔊♩♪♫♬♩♪♫♬♩♪♫♬
  • xschop
    xschop Posts: 2,022
    Why'd you pop in here like that? Now I want some midwoofer outer rings. Care to take a screwdriver to them to see how they attach? Hehe.
  • VR3
    VR3 Posts: 24,484
    The lsim did it like this, the rubber trim ring clicked into the grooves you see in the basket

    bdv6iy9oiawe.jpg
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • JayCee
    JayCee Posts: 1,176
    edited March 2020
    xschop wrote: »
    Why'd you pop in here like that? Now I want some midwoofer outer rings. Care to take a screwdriver to them to see how they attach? Hehe.

    LOL. Uhmmm, won't say I haven't had the thought cross my mind. In my case...I've measured the diameter and think I can get both the L200's new tweeter AND the midwoofer to fit in a pair of original "Legend" SDA's. Just need 2 more MW's to make it doable. Merely, mind you, in the name of science. Somehow, I think @F1nut wouldn't be amused, nor would I be invited to a future demo. :neutral:

    Nothing ventured, nothing gained. Kind of seems to be the @xschop mantra...:wink:
    Speakers: Polk1.2tl's (Uber Mods) Pre/Amp/DAC: PS Audio BHK Signature & 250, DirectStream Cables/IC's: MIT S1Bi-Wire/S1 Balanced +Avel Lindberg 1000VA "Dreadnought" Power Conditioner: PS Audio P15 Power Plant Power Cords: Core Power Technologies Gold, DH Labs Power Plus DIY w/Neotech NC-P301 & P311ends Streamer: Roon ROCK on wifi'd NUC & Uptone EtherREGEN⟿Ω☯☥☮⟿🔊♩♪♫♬♩♪♫♬♩♪♫♬
  • westmassguy
    westmassguy Posts: 6,725
    skrol wrote: »
    I'm curious... By removing the dust cap, doesn't it allow more air leakage in an otherwise sealed cabinet? I realize that there is normally a small amount of leakage.

    The existing dust caps are mesh. Leakage is through the spider, which is treated cloth.
    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer
    Cables: Speaker: Furez 10/2 with GLS Locking Banana Plugs
    Interconnect: Furez 10/2 with SpeakONs
    ICs: Custom Furez by Douglas Connections
    Den:
    Bose 901 Series II Continentals Restored, Re-Built Equalizer with Elna Silmic IIs, Sonicaps, and Silver Mica Caps
    Carver CT-3 Pre, Carver C-500

    dhsspeakerservice.com/



  • F1nut
    F1nut Posts: 45,740
    JayCee wrote: »
    xschop wrote: »
    Why'd you pop in here like that? Now I want some midwoofer outer rings. Care to take a screwdriver to them to see how they attach? Hehe.

    LOL. Uhmmm, won't say I haven't had the thought cross my mind. In my case...I've measured the diameter and think I can get both the L200's new tweeter AND the midwoofer to fit in a pair of original "Legend" SDA's. Just need 2 more MW's to make it doable. Merely, mind you, in the name of science. Somehow, I think @F1nut wouldn't be amused, nor would I be invited to a future demo. :neutral:

    Nothing ventured, nothing gained. Kind of seems to be the @xschop mantra...:wink:

    I most definitely would not be amused.
    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

  • xschop
    xschop Posts: 2,022
    VR3 wrote: »
    The lsim did it like this, the rubber trim ring clicked into the grooves you see in the basket

    bdv6iy9oiawe.jpg
    VR3 wrote: »
    The lsim did it like this, the rubber trim ring clicked into the grooves you see in the basket

    bdv6iy9oiawe.jpg

    Hey thanks VR3. I have some large diameter plastic I can practice on. Would it be a benefit to actually make them and mount you think?
  • xschop
    xschop Posts: 2,022
    JayCee wrote: »
    xschop wrote: »
    Why'd you pop in here like that? Now I want some midwoofer outer rings. Care to take a screwdriver to them to see how they attach? Hehe.

    LOL. Uhmmm, won't say I haven't had the thought cross my mind. In my case...I've measured the diameter and think I can get both the L200's new tweeter AND the midwoofer to fit in a pair of original "Legend" SDA's. Just need 2 more MW's to make it doable. Merely, mind you, in the name of science. Somehow, I think @F1nut wouldn't be amused, nor would I be invited to a future demo. :neutral:

    Nothing ventured, nothing gained. Kind of seems to be the @xschop mantra...:wink:

    Boredom brings about the many mods. BTDT.

    Give it a go with a flathead. Just don't tell F1 lol.
  • xschop
    xschop Posts: 2,022
    skrol wrote: »
    I'm curious... By removing the dust cap, doesn't it allow more air leakage in an otherwise sealed cabinet? I realize that there is normally a small amount of leakage.

    The existing dust caps are mesh. Leakage is through the spider, which is treated cloth.

    The REAL question is whether the spider or the voice coil clearance is the limiting factor for the air blow by. It really doesn't matter as the PR push test is telling that it's not the porous dust cap.

  • xschop
    xschop Posts: 2,022
    Tom Petty's vocals improve undoubtedly.
  • xschop
    xschop Posts: 2,022
    edited April 2020
    More Polk MW intriguing findings. I was about to start more mods (regular magnet glueing and butyl-mat application..and cleaning up more of the dust cap glue area ala mhardy technique, when I found what I believe is contributing to the slight magnetic off-kilter pull feeling when I insert the phase plug with attached steel disc.....

    It (VC) was not rubbing at first, but I could clearly see the VC was off center. After looking at the back magnet area while turning, I heard a distinguished "click o' death"....



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  • xschop
    xschop Posts: 2,022
    edited April 2020
    You can set two concentrics with half their circumference....
    C=pi(D)
    0.995×3.14/2= 1.56

    We'll just go with 1.5" width of porous vinyl material and 2.5" long to allow for thumb grab.....
    I have quite a bit of spare vinyl thicknesses at home and don't have my mics to post exact thickness, but it's close to 0.020" thick with calipers.
    The porous vinyl allows for detachment after VC is reset without harming the VC coating which may be PTFE from look and feel...

    I purposely gave this one the "click o' death" about 5 times and then reset....and the method works. I'll be gluing the magnet and pole piece shortly...

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  • xschop
    xschop Posts: 2,022
    edited April 2020
    At home today, had 5b's opened up. Curiosity wouldn't let me glue up the magnet just yet because although tightly glued from factory, the pole piece to magnet is offset. Just doesn't look right. Anybody else see this before?

    Anyways, after separating them from the basket plate, now the steel washer will not set concentric due to the heavy magnet pull in 2nd pic. It still had a slight pull when VC was recentered and all together, so I think I'll err on caution and see what type double-sided tape I can use and then center the phase plug with the 0.020" thick full circumference vinyl sheet....
    Also to note, after I separated steel shim from phase plug (3rd pic), I checked and it would not even pic up a small steel staple, so it did not become magnetized itself during its hiatus in the hole.

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  • BlueBirdMusic
    BlueBirdMusic Registered User Posts: 1,475
    @xschop, interesting stuff on this thread.

    I am curious.

    What kind of toys did you have as a kid?

    What did you do to modify them?

    Harry
    If the telephone doesn't ring ......... it's me
    Harry / Marietta Georgia
  • VR3
    VR3 Posts: 24,484
    Technically there would be less diffraction by having a ring that curved from the surround to the cabinet baffle face. So there could be some sonic benefits
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • xschop
    xschop Posts: 2,022
    @xschop, interesting stuff on this thread.

    I am curious.

    What kind of toys did you have as a kid?

    What did you do to modify them?

    Harry

    Lincoln Logs and an Erector Set, that mom knew about.
    If she ever found the go-cart we modified with a 6Hp Briggs and Stratton with knobby tires hidden down at the creek lol. We got airborne multiple times...
  • xschop
    xschop Posts: 2,022
    edited May 2020
    I made a dual purpose tool to re-center the pole-piece and magnet as well as center the phase plug perfectly if glued on.

    I made my 5B plugs removeable by tapping the pole-piece and phase plug 3/8-16. Will get some proper set screws but a bolt will work also.
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    Post edited by xschop on
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