Must try MOD - Foam inside the stamped steel baskets - YES!

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  • xschop
    xschop Posts: 4,704
    edited December 2021
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    I've since found a thicker aftermarket butyl mat that I'm now using. The original 6502's that I ever matted (@ 3 yrs ago) still have the power grab/butyl mat because the original mat adhesive was dried at the time. I tried recently removing it to add the new thicker butyl mat. It would not budge...

    I'll also add that for the fiberboard enclosure back walls on the modded 5Jr's Ive done, I had to paint/primer to get the foam pad adhesive to really stick.

    From a chemical standpoint, the formaldehyde glue of the particle board oxidizes over time to a thin layer of yellowish dust (formic acid).

    Don't take experimental gene therapies from known eugenicists.
  • Gardenstater
    Gardenstater Posts: 4,187
    edited December 2021
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    Thankfully no I did not put the foam on the inside of the spokes.

    Ahh I think we found your problem.

    I'm highly doubtful I'd be able to hear a .4 db change perhaps not even 40 years ago. Kudos to you for having such acute hearing and hopefully the armacell has a much better grip and stays in place for your mod.

    I'm not sure I heard the sPL difference (ehh actually I did because the center image was a bit skewed to one side). What I heard was greater clarity in vocals. That of course isn't the only area but that is just what came to my attention first. It was only when I did the other speaker too, and rebalanced with whitenoise again that I went, WHOA what the hell this sounds fantastic. Everything has greater clarity and nuances. Vocals and piano especially but everything.

    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
  • Toolfan66
    Toolfan66 Posts: 16,908
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    VR3 wrote: »
    Fwiw, having Sean's 1.2tl here, even cleaning the cabinet walls, black hole 5 was coming off after a month. I ripped it back off and used power grab to reattach and even two months later was super secure

    I don't recall having that problem, maybe I should pop mine open and just double check..
  • Toolfan66
    Toolfan66 Posts: 16,908
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    xschop wrote: »
    Hopefully he doesn't consider the uber-mods naughty. I may never know what potential the XS-0198's could have achieved...

    nga8909qhpkt.jpg

    What is going on here? did you add a chunk of aluminum on the back of the magnet??
  • motorstereo
    motorstereo Posts: 2,052
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    Thankfully no I did not put the foam on the inside of the spokes.

    Ahh I think we found your problem.

    I'm highly doubtful I'd be able to hear a .4 db change perhaps not even 40 years ago. Kudos to you for having such acute hearing and hopefully the armacell has a much better grip and stays in place for your mod.

    I'm not sure I heard the sPL difference (ehh actually I did because the center image was a bit skewed to one side). What I heard was greater clarity in vocals. That of course isn't the only area but that is just what came to my attention first. It was only when I did the other speaker too, and rebalanced with whitenoise again that I went, WHOA what the hell this sounds fantastic. Everything has greater clarity and nuances. Vocals and piano especially but everything.

    So it would've been better to have the strips fall off from the inside of the spokes? :)
  • Gardenstater
    Gardenstater Posts: 4,187
    edited December 2021
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    Ha ha no that isn't what I meant. I was referring to the fact that you said you didn't notice any difference in sound. This mod is about putting it inside the basket only, in order to absorb some of the backwave that would've mostly bounced around inside the basket and some of it would be perceived as distortion when it hits and transmits through the back of the cone, conflicting with the desired audio signal expression.

    That stuff you used and what I used is not at all what you want for damping of mechanical vibrations. And also speaker enclosure volume needs something much more substantial and thick like the 6" x 6" BH5 to notice any appreciable amount of standing wave absorption etc. in my opinion, and born out by your experience. I also doubt that weatherstripping foam is at all the right stuff because it has a smooth shiny skin on it usually (at least the stuff I have used), to make a seal against a window or door. The Armacell by the way, is closed cell but it isn't smooth or shiny.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
  • motorstereo
    motorstereo Posts: 2,052
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    VR3 wrote: »
    Fwiw, having Sean's 1.2tl here, even cleaning the cabinet walls, black hole 5 was coming off after a month. I ripped it back off and used power grab to reattach and even two months later was super secure

    No doubt this is the best way to secure them. My way was to use my air stapler and shoot a couple of staples into each strip so I could button the speakers right back up. I also cleaned the backs first with lacquer thinner. One of the strips was just a tad crooked which I unsuccessfully tried to reposition as that adhesive held tight despite my efforts. I felt that any more tugging on that strip would've resulted in taking off some of the wood with the adhesive and I certainly did not want that. Being that I'm not a fan of opening up my speakers I wanted to be doubly sure there would not be a problem like the falling foam strips were. After reading about your issues I'm glad now that I did secure them a bit more.
  • xschop
    xschop Posts: 4,704
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    Toolfan66 wrote: »
    xschop wrote: »
    Hopefully he doesn't consider the uber-mods naughty. I may never know what potential the XS-0198's could have achieved...

    nga8909qhpkt.jpg

    What is going on here? did you add a chunk of aluminum on the back of the magnet??

    Those are back-chambered RDO's with lamb's wool in the chamber and pole-piece.
    I re-posted the pic because this mod mirrors the same mechanical concept/backwave correction that Gstater's basket frame mod is accomplishing.
    Don't take experimental gene therapies from known eugenicists.
  • Toolfan66
    Toolfan66 Posts: 16,908
    edited December 2021
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    xschop wrote: »
    Toolfan66 wrote: »
    xschop wrote: »
    Hopefully he doesn't consider the uber-mods naughty. I may never know what potential the XS-0198's could have achieved...

    nga8909qhpkt.jpg

    What is going on here? did you add a chunk of aluminum on the back of the magnet??

    Those are back-chambered RDO's with lamb's wool in the chamber and pole-piece.
    I re-posted the pic because this mod mirrors the same mechanical concept/backwave correction that Gstater's basket frame mod is accomplishing.

    Do you have more pics of this piece before install? Also, how are you securing it to the tweeter?
  • xschop
    xschop Posts: 4,704
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    Toolfan66 wrote: »
    xschop wrote: »
    Toolfan66 wrote: »
    xschop wrote: »
    Hopefully he doesn't consider the uber-mods naughty. I may never know what potential the XS-0198's could have achieved...

    nga8909qhpkt.jpg

    What is going on here? did you add a chunk of aluminum on the back of the magnet??

    Those are back-chambered RDO's with lamb's wool in the chamber and pole-piece.
    I re-posted the pic because this mod mirrors the same mechanical concept/backwave correction that Gstater's basket frame mod is accomplishing.

    Do you have more pics of this piece before install? Also, how are you securing it to the tweeter?

    Where were you lol? I believe I have the only two sets back-chambered on the planet. Thanks to VSAT's enabling thread lol....

    https://forum.polkaudio.com/discussion/168239/a-real-sl-2000-hack-replace-stock-burnt-voice-coils-with-silk-diaphragm-dome/p15

    I got the oil-doped silk Wuhans sounding better than the factory RD0-194's. I can't say that about the 198's as I have now A-B'd those in the 8TLs now in the back-chambers.

    I now have Blue-Loctite with the pole-piece to billet chamber interface to answer your question.
    Don't take experimental gene therapies from known eugenicists.
  • audioluvr
    audioluvr Posts: 5,437
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    So I often take @Gardenstater comments with a grain of salt (no offense) but this mod may be legit due to the basket being in such close proximity to the cone. I'm planning on upgrading my SDA 1C's driver circuit caps, internal wiring and speaker cable posts and may actually consider this as well. Unfortunately I won't be able to comment on whether it helps due to the other mods but WTH. Blind faith can be awesome!
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)


    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
  • Gardenstater
    Gardenstater Posts: 4,187
    edited December 2021
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    Ha ha welcome aboard. Any port in a storm eh? No need to trust me, trust Richard Vandersteen

    https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=5073948A&KC=A&FT=D&ND=3&date=19911217&DB=EPODOC&locale=en_EP

    x9rq80ypmlfo.jpg

    4wbbsdoyrh74.jpg


    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
  • Tony M
    Tony M Posts: 11,017
    edited December 2021
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    Right under the red outlined box there is another fact about reflected waves that bounce back from the magnet and basket "being even more severe". I'd like to see more of that paragraph.
    Most people just listen to music and watch movies. I EXPERIENCE them.
  • F1nut
    F1nut Posts: 49,802
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    No need to trust me, trust Richard Vandersteen
    No thanks, horrible speakers.
    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

  • Gardenstater
    Gardenstater Posts: 4,187
    edited December 2021
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    Oh well. I don't remember if I heard/saw them or not. I think maybe 10 yrs ago at the New York Audio Show but that was back when there were so many high end exhibitors that it is a blurr. I *think* I was impressed and I remember something that wasn't too appealing to me, looking like a red stealth fighter. Anyway, the man is definitely not one to be lazy or stupid and is not striving for mediocrity, to say the least:

    Searching for the Extreme: Richard Vandersteen of Vandersteen Audio: Part One

    https://www.ultraaudio.com/features/20090901.htm


    Searching for the Extreme: Richard Vandersteen of Vandersteen Audio: Part Two

    https://www.ultraaudio.com/features/20091001.htm


    I have to verify but these might be his driver technology licensed to ScanSpeak of Denmark:

    https://www.scan-speak.dk/product-families/illuminator/
    Post edited by Gardenstater on
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
  • Gardenstater
    Options
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
  • xschop
    xschop Posts: 4,704
    edited December 2021
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    Now Bose I'd agree with, on the horrible speakers comment.

    So from the paper/patent, we can deduct that MW baskets are echo chambers and severity depends on frame to window area measurements/sizes?
    ....makes sense
    Post edited by xschop on
    Don't take experimental gene therapies from known eugenicists.
  • Tony M
    Tony M Posts: 11,017
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    Thank you. ;)

    I thought there was going to be a longer story on those reflections. :#
    Most people just listen to music and watch movies. I EXPERIENCE them.
  • Gardenstater
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    Ha ha no problem Tony. You should read the patent and look at the figures. It's pretty interesting and easy to understand and follow. It is interesting that he first shows his ideal design and then in figures 4 - 6 he basically shows what you can do with a more traditional stamped steel basket which is what we are dealing with. xschop - it would be awesome if we could get some thin foam between the spider and the basket/upper plate pole piece like in figure 5 of the patent. When you took one apart did you see how much clearance there was? Probably isn't enough but just wondering. Yes the frontal area of the spokes plus the magnet assy are the reflective areas. It is a very large percentage of the total area with our MW drivers.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
  • Tony M
    Tony M Posts: 11,017
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    I have seen some cast baskets that have thinner spokes. I wonder if that was done for this topic of reflections.

    Yesterday, I thought about an amplifier's SLEW rate, I think it's called. Where the amp senses the back wave elec. signal and stops the speaker's movement.

    Subwoofer's servo controls do this, I think.
    Most people just listen to music and watch movies. I EXPERIENCE them.
  • xschop
    xschop Posts: 4,704
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    I listened to the 8Tl's yesterday at shop for a little while after them being on burn in all week radio FM channel....

    Impeccable imaging and clarity. More dynamic than the 5B's given the extra Midwoofer obviously. Incredible realism. Your mod is a keeper.
    Don't take experimental gene therapies from known eugenicists.
  • Gardenstater
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    #170 in the figure is the foam we would want.

    3dz823csuezv.jpg
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
  • Gardenstater
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    Tony M wrote: »
    I have seen some cast baskets that have thinner spokes. I wonder if that was done for this topic of reflections.

    I think so no doubt. This patent is old and expired and anybody can do that now.

    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
  • pitdogg2
    pitdogg2 Posts: 24,579
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    Yesterday, I thought about an amplifier's SLEW rate, I think it's called. Where the amp senses the back wave elec. signal and stops the speaker's movement.

    Are you sure you're not confusing that with dampening factor
  • F1nut
    F1nut Posts: 49,802
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    Tony M wrote: »
    I have seen some cast baskets that have thinner spokes. I wonder if that was done for this topic of reflections.
    No, the cast aluminum baskets have thinner spokes because that's all that's needed for their structural integrity.
    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

  • Tony M
    Tony M Posts: 11,017
    edited December 2021
    Options
    pitdogg2 wrote: »
    Yesterday, I thought about an amplifier's SLEW rate, I think it's called. Where the amp senses the back wave elec. signal and stops the speaker's movement.
    Are you sure you're not confusing that with dampening factor

    I believe you're right. ;) I think I read somewhere anything more than 50 is overkill.
    Like another member just said about time flying, it's been supersonic speed for me.
    But then again, at my age...I'm getting things wrong more often. My memory is scatterbrained it seems with all I'm doing the past few years as I got heathier. Body got healthier, brain, not so much. :D
    Most people just listen to music and watch movies. I EXPERIENCE them.
  • xschop
    xschop Posts: 4,704
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    F1nut wrote: »
    Tony M wrote: »
    I have seen some cast baskets that have thinner spokes. I wonder if that was done for this topic of reflections.
    No, the cast aluminum baskets have thinner spokes because that's all that's needed for their structural integrity.

    Plus there's less surface for reflections.

    Don't take experimental gene therapies from known eugenicists.
  • F1nut
    F1nut Posts: 49,802
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    xschop wrote: »
    F1nut wrote: »
    Tony M wrote: »
    I have seen some cast baskets that have thinner spokes. I wonder if that was done for this topic of reflections.
    No, the cast aluminum baskets have thinner spokes because that's all that's needed for their structural integrity.

    Plus there's less surface for reflections.

    Stop.
    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: 4,704
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    Sorry F1, I've just begun. There's still performance to be had. I'll be relocating the terminal tabs next to remove them from the equation. I don't like them blocking the windows.
    Don't take experimental gene therapies from known eugenicists.
  • VR3
    VR3 Posts: 28,042
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    I think you guys are over analyzing this one a little bit :-p
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.