Phase Plug design for MW65xx

13468914

Comments

  • xschop
    xschop Posts: 4,636
    Mix with water till you get a watery cream consistency then apply a light sheen.
    Don't take experimental gene therapies from known eugenicists.
  • Gardenstater
    Gardenstater Posts: 4,137
    That's a good thought. What are the Polk cones made of? Anybody know? I'm sure I see a weave pattern.
    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: 4,636
    edited April 2022
    They are just cellulose paper and the die they were pressed on had that pattern I believe.
    Don't take experimental gene therapies from known eugenicists.
  • gp4jesus
    gp4jesus Posts: 1,969
    xschop wrote: »
    From your tweeter felt thread pics, those RTi Mids look like 1' VC dust cap sizes.
    So in spite of a ~1.5”* dust cap, you believe Polk followed suit w/VC size from their other 6.5” mids? BTW I’m gonna buy the ‘A7 mid - $42 shipped. That allows me to complete the driver mods at my (slow) pace followed by a quick swap. Further, for evaluation** purposes, I want take these mods one step, one driver/channel at a time. I want hear the “inner foam” mod in one channel.
    *a quick take w/a tape measurer
    **to add to the “inner driver foam” mod’s credibility.
    xschop wrote: »
    Knowing Polk's Mfg techniques pretty much (1” VC*) is almost a given.
    *Yes? Still need some direction to obtain those other 2 driver specs in a previous post. As soon as the driver arrives, I’ll post pics or short video w/ the shield removed. Either that or George can coach me by phone
    xschop wrote: »
    I'd also be interested in the RTi MW outer ring dimensions. Maybe they could be modded to fit the vintage MW outer edges?
    Maybe…
    All in good time “Mi tweeker amici!
    (Italian for “my tweeker friends”)

    Tony

    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • xschop
    xschop Posts: 4,636
    Besides confirming 1" diameter pole-piece, the length from the top of the pole-piece to the base of cone where it meets spider is needed. This distance determines where the base of the plug needs to begin as I've seen this referenced in some literature about it...

    One of Jazz Head's 6500 plugs...

    wol8v640yenv.jpg
    Don't take experimental gene therapies from known eugenicists.
  • Gardenstater
    Gardenstater Posts: 4,137
    edited April 2022
    gp4jesus wrote: »
    So in spite of a ~1.5”* dust cap, you believe Polk followed suit w/VC size from their other 6.5” mids?

    The dust caps I cut off of my MW6500s all were around 1.5" - 1.6" dia., depending upon how much of the glue you tried to take with it. Dust caps have to be large enough to hide the wires and sometimes they make them large enough to also hide where the wires are soldered to pass through the cone to the tinsel leads.

    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
  • gp4jesus
    gp4jesus Posts: 1,969
    @gp4jesus I think you or someone else will have to donate/lend one for dissection to make it happen. I saw some for sale in the flea market I think, for $25.
    A7 mid is here ($42 later)!

    I think the phase plug mod is off the table for RTi A series mods. Is major disassembly part of the process? The mag shields are glued on!

    Side note: 6-7 year old Armacell adhesive sticks to the “peel-off backing too well while separating from the foam too easily! I’ve spent a half hour peeling off just 3” of the same - ARGH!
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • Gardenstater
    Gardenstater Posts: 4,137
    edited April 2022
    gp4jesus wrote: »
    @gp4jesus I think you or someone else will have to donate/lend one for dissection to make it happen. I saw some for sale in the flea market I think, for $25.
    A7 mid is here ($42 later)!

    I think the phase plug mod is off the table for RTi A series mods. Is major disassembly part of the process? The mag shields are glued on!

    Side note: 6-7 year old Armacell adhesive sticks to the “peel-off backing too well while separating from the foam too easily! I’ve spent a half hour peeling off just 3” of the same - ARGH!

    Hey Tony! You could cut the dust cap off the one you care about least, although it shouldn't get damaged if you are careful and don't get too close to the wires. Then you wouldn't need anything but a small ruler to measure the depth from the surface of the cone to the top of the pole piece.

    As far as the inside diameter of the voice coil and outside diameter of the pole piece, well that is a bit more difficult and I'd want to have a caliper and some shims to determine those, at least close enough. Yes those can be done without further disassembly......of magnet etc..

    PS: It would also be good to know the depth of the pole piece relative to the high point of the cone/point where the surround begins. Can be measured with the small ruler closely enough.
    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
  • gp4jesus
    gp4jesus Posts: 1,969
    @Gardenstater (George)

    Thanks for the encouragement to do the Plugs. My current source of pain is the Armacel.

    I’ve been pluggin’ away non-stop for over an hour to peel enough to cover just the exterior of…
    b8i35mstig2f.jpeg

    …this - almost finished. Should I PU fresh Armacel to do the cone side?

    Remember: gonna “foam*” only this driver then swap & listen. During the swap, I hafta do a little BP maintenance as one of these…
    *cone side too

    kg4yo5kbao46.jpeg

    …has a loose locking nut inside. Very soon gonna go all in on spades for all my LCR drivers @ both ends - 42 if my math is correct.

    Side note: in the market for 1” long gold* plated copper BPs - these are plated* brass. Has ~1/3** the conductivity of copper.
    **or less.

    Thank. Tony
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • Gardenstater
    Gardenstater Posts: 4,137
    Yeah if it was me I guess I'd want to use fresh for the inside, but if you feel that the stickiness is still good then no problem. I cleaned the inside with some alcohol on a cotton swab first. You can cut a trial piece leaving the backing on to check the fit until you get it right and then use that one as the template for the other ones. I'd recommend doing the other area between the spokes too provided it is a decent area and won't interfere with anything.
    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
  • gp4jesus
    gp4jesus Posts: 1,969
    7ead8vgw8wzw.jpg
    Gonna go “fresh.” Also while taking this I discovered a portion of magnet/frame area that demands covering to fall in line w/this mod. Not to further damp the shield - I did that sufficiently. But to prevent unwanted reflection. I hate that I have overlooked this until now.

    Fortunately, since I hafta pull all the mids ANYWAY for other reasons… Following the foaming of the cone side*, if I have the energy I’ll swap it in tonight as I’m taking my 12 year old to a place (@6p) less than 5 minutes from Lowe’s…

    Notice in the above pic the frame spokes look different from the 6500? Would you complete the cone side then finish outside? Less likely to accidentally stick to “foamless” spokes?

    Also see how the spider…

    vhbyt9ru0p3d.jpg

    …meets the frame? Are the 6500s like that?

    Thanks for reading this far. Tony
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • Gardenstater
    Gardenstater Posts: 4,137
    edited April 2022
    gp4jesus wrote: »
    7ead8vgw8wzw.jpg
    Gonna go “fresh.” Also while taking this I discovered a portion of magnet/frame area that demands covering to fall in line w/this mod. Not to further damp the shield - I did that sufficiently. But to prevent unwanted reflection. I hate that I have overlooked this until now.

    Fortunately, since I hafta pull all the mids ANYWAY for other reasons… Following the foaming of the cone side*, if I have the energy I’ll swap it in tonight as I’m taking my 12 year old to a place (@6p) less than 5 minutes from Lowe’s…

    Notice in the above pic the frame spokes look different from the 6500? Would you complete the cone side then finish outside? Less likely to accidentally stick to “foamless” spokes?

    Also see how the spider…

    vhbyt9ru0p3d.jpg

    …meets the frame? Are the 6500s like that?

    Thanks for reading this far. Tony


    Nope. You have much less area there for reflection, and it looks like the outer spider is more active than in the earlier ones. I'd be inclined to let well enough alone and skip that area in your case as it seems like the angle of reflection would be such that it would not be directed back at the cone. I *would* try to run the spoke pieces up to as close to the spider as you feel comfortable though.

    Regarding the order, I didn't have any trouble doing the inside after outside but that was with Dynamat for the outside of the spokes.
    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
  • gp4jesus
    gp4jesus Posts: 1,969
    Nope. You have much less area there for reflection, and it looks like the outer spider is more active than in the earlier ones. I'd be inclined to let well enough alone and skip that area…
    the spider extends to the frame, absolutely no horizontal space to cover. Spokes very nearly “touch” the spider.
    I *would* try to run the spoke pieces up to as close to the spider as you feel comfortable though.
    I believe the toughest part is above where spokes meet the frame. Then goes vertical (~1:4”)to then meet the cone’s surround.
    Regarding the order, I didn't have any trouble doing the inside after outside but that was with Dynamat for the outside of the spokes.
    Is Dynamat as shiny in person as it appears on this forum?

    Side note: I believe this driver has break-in to go. It’s kinda stiff compared to my installed mids. Perhaps I should swap them now and “foam” a thoroughly broken in driver.

    Waiting for Natale to finish.

    Many, many thanks. Tony
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • Gardenstater
    Gardenstater Posts: 4,137
    This should've been in the foam inside the basket mod thread :) but why stop now....

    Tony, what I was referring to is the area between the first convolute of the spider and the basket edge. Even though it appears to be a part of the spider still, it is more of a glue flange for the spider and could be a slightly reflective surface. If I *was* going to foam it, it would be the area shown by the red lines. I am still thinking you could just leave it be though, although I would extend the foam on the inside of the spokes up almost to that first convolute, even though it goes over the glue flange for the spider.

    hpv4vuk8l63h.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
  • xschop
    xschop Posts: 4,636

    Cut the cap off already... :)
    Don't take experimental gene therapies from known eugenicists.
  • gp4jesus
    gp4jesus Posts: 1,969
    xschop wrote: »
    Cut the cap off already... :)
    😂😂 I appreciate your eagerness to see this go forward. George: talk to this guy. Explain to him the process.

    One step at a time, please. I want to hear these w/ cone side foamed. First the one. Then together.

    BTW this driver is the “spare*.” I finished foaming the outside. Then I completed the BP maintenance. Necessary because the BP would spin, not allowing removal of the spades. Had to disconnect from the amp side.
    As of midnight, the spare in the cabinet.
    *the guinea pig for the plug surgery

    If the two kids, four dogs, and other unconnected responsibilities* allow, I’ll foam the cone side of the broken-in mid today; swap; and listen😊.
    *some light in-the-crawl-space plumbing** to continue on a back deck. Some tile repair in the master bath.
    **necessary part of the backyard face lift

    George: gonna send you a PM

    Thanks for everyone’s patience.
    Tony
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • xschop
    xschop Posts: 4,636
    edited April 2022
    Just razzing you.
    It would be interesting to calc. the difference between vintage MW and RTi frame surfaces.
    Don't take experimental gene therapies from known eugenicists.
  • gp4jesus
    gp4jesus Posts: 1,969
    edited April 2022
    @xchop so sorry for coming across 😢😞 - not my intent.

    @Gardenstater et al

    p8tfxz0v47vj.jpeg

    The last 1/4” of spider, the flat part just to the left of the spider ripple has frame underneath. Also if you look carefully…

    j9hkta5ea4bv.jpeg
    omfafdo5icq4.jpeg

    …the DC is about 1 5/8” while under the cone, the VC obviously much smaller ~an inch by my tape measurer
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • gp4jesus
    gp4jesus Posts: 1,969
    @Gardenstater

    p8tfxz0v47vj.jpeg

    The last 1/4” of spider, the flat part just to the left of the spider ripple has frame underneath.
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • xschop
    xschop Posts: 4,636
    You need the foam on the inside of the frame uprights too.
    Don't take experimental gene therapies from known eugenicists.
  • gp4jesus
    gp4jesus Posts: 1,969
    Yeah, to me that’s the “cone side” of the frame.

    About to lay the first piece😊
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • xschop
    xschop Posts: 4,636
    :)
    Don't take experimental gene therapies from known eugenicists.
  • gp4jesus
    gp4jesus Posts: 1,969
    @Jazzhead:

    I included 3-layer Sonic Barrier in my PE order - 2 sheets, likely double what I need for both A7s and my A6 center*, but one speaker at a time.
    *between 1 1/2 to 1 3/4 the size for its 2 mids.

    Where and how much SB to place in the Mid cavity*?
    13.5(D) X 7.25(W**) X 12.25(H) = 1198.97” actually smaller than the calculated .69385 as this does not account closure shape, the port, or the driver itself
    **widest dimension

    g3y2j7aqnb3q.jpeg

    @xschop:
    Driver detail update Cone diameter - 4 1/2” ; Including surround - 5 11/16”

    @Gardenstater the “ foamed” mid is, in the upper registers of its bandpass* - 125hz - 2.25Khz both LR 4th order, a smidge quieter* and hear a noticeable difference in raspiness . I left the BSC filter “on” during all listening.

    Thanks again for everyone’s help. Tony
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • Gardenstater
    Gardenstater Posts: 4,137
    You might need to rebalance the channels slightly in the meantime. When will you be able to do the other speaker? Baffle Step Compensation? ........schmanzy fancy!
    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
  • gp4jesus
    gp4jesus Posts: 1,969
    You might need to rebalance the channels slightly in the meantime.
    meh… yeah I cudda & shudda the last time I was in the “Speaker Setup” menu… thanks for helping me to remember I DO have a balance control. OTOH I think my R Ch’s tweeter is on the way out. Fortunately, PE had sent the 1/10 Dayton tweeters I ordered in the shipment. The other 9 await restock @ the end of June😢.
    When will you be able to do the other speaker?
    When I get 4+ hours. But I think I’m gonna simplify things by trying to break-in the spare in my shop & finish foaming along the way. Then it’s little more than a swap.
    Baffle Step Compensation? ........schmanzy fancy!
    😂😂 I have the DSP, why not?! A high cut shelving filter, 6dB slope, corner frequency ~575hz* IIRC.
    *per a BSC calculator and a lengthy RTA session

    Some pics of tools and an application tip that for which George deserves all the credit.

    Place the sticky end.

    fuho6pept4hc.jpeg

    wr5qe8wl8vc8.jpeg

    Then w/the hemostats reach behind and peel while pressing & smoothing from the other side

    3i7z5d18v7kc.jpeg

    I corrected one other thing that has bothered me for some time…
    8f90xa0ghhmq.jpeg

    They came silver as do rings around mids, woofers, ports, & tweeter* bezels*. Always struck me as tacky. I’ll eventually paint* them all.
    *as I replace them

    2gacngv0dtei.jpeg

    Bad lighting and the camera angle makes ‘em look dark gray.

    @xschop after I make the next swap, I’ll begin the “exploratory surgery” for the last pieces of info for the plugs.

    Thanks everyone. Tony
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • xschop
    xschop Posts: 4,636
    I think what's nice about those mids is they wont need any felt or paint like the MW65xx's to remedy the untreated area left exposed under the dust cap. Id say trim as close as yo can get to the lip of the dust cap itself, but not attempt any of the lip that is actually glued to the cone unless you're a vascular surgeon. ;)
    Don't take experimental gene therapies from known eugenicists.
  • gp4jesus
    gp4jesus Posts: 1,969
    edited April 2022
    😂Vascular surgeon😂!

    I’m sorry y’all are my ears on this stuff. Nobody here cares one way or the other.

    Per my style*, I’m gonna take it slow*. In between everything else I’m gonna go to pg 1 of this thread to carefully examine everyone’s foot steps.
    Side note: these cones appear to be plastic or similar w/rubber surrounds**. What’s the 65XX material?
    *I make a sloth look like the Roadrunner😂! Too many other unrelated time-consuming projects about half are “honey doos to boot
    **should last forever. I have a pair of Meridian M2 speakers from 1983(?) w/ the original rubber surrounds

    I’ll keep y’all posted WHEN I think I’m ready to begin the surgery. Meanwhile, though I haven’t done it yet, gonna use a NAD 3020 to power the break-in. Also gonna PM Jack* for some history.
    *seller

    @Jazzhead or anyone else - Sonicbarrier suggestions, warnings etc? Seems “less is more” is the rule. I also have a bunch of mineral wool at my disposal. But all that for another session

    Happy Resurrection Sunday everyone!
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • Jazzhead
    Jazzhead Posts: 520
    @gp4jesus

    Sorry for the late reply, been awol... I've never heard your model of speakers. Experiment and trust your ears. Others more knowledgeable than I can chime in but could start with a 4x5 piece behind the midrange driver and see how they sound. Live with them for a while. Listen to well-recorded music that you have known for decades. The basket foam mod may have an effect as well, so it can be good to do each independently and evaluate. You can go bigger or smaller with SB until you optimize.
    Polk Audio first generation RTA-12s; 12 inch Polk Stands; DHS Speaker Service upgraded crossovers w/ Sonicap/Mills; the "westmassguy anti-lobing mod" (hyperdamped outer drivers/mirror imaged); tweeter anti-diffraction mod; Cardas binding posts; Neotech UPOCC internal wire; foam-lined inner driver baskets; xschop phase plugs; deleted fuses; Hurricane nuts; Sonic Barrier; Dynamat Xtreme
    Ayre K-5xeMP preamplifier
    Cambridge Audio 840C CD player; Herbie's Audio Lab Super Black Hole CD Mat
    D-Sonic Custom Audio M3a-600M monoblock amplifiers
    NAD 4155 FM/AM tuner
    Silnote Audio Morpheus Reference II Series II balanced interconnects; Virtue Audio single-ended interconnects
    Kimber 12TC speaker cable w/Furez connectors; VH Audio Flavor 4 power cables w/Furutech connectors
    Herbie's Audio Lab system isolation: Tenderfeet, Big Fat Dots, Grungebuster Dots, Little Fat Gliders
    Dedicated 20A/10 AWG circuit; Furutech GTX-D (G) outlet; Furutech eTP80; Shunyata Research Venom Defender; Synergistic Research Orange fuses
  • xschop
    xschop Posts: 4,636
    Putting a feeler out here. I'll be making another large batch of these soon and also will be making them for the RtiA midwoofers too. PM if interested. I'm considering doing a conversion service for both models if the RTiA's work out.
    Don't take experimental gene therapies from known eugenicists.
  • Jazzhead
    Jazzhead Posts: 520
    Happy Birthday America and a good 4th to all you fine Polkies. I finally got around to installing the @xschop phase plugs. The "surgery" went well and the sonic results make it well worth doing. I've gained across-the-board clarity and improvement in imaging/soundstage. I'm hearing more realistic reproduction, particularly in the range of vocals, strings, cymbals, drums. As @Gardenstater said these plugs introduce more detail and smoothness. Strings and synthesizers have a more realistic buzz, the overhanging tone of a cymbal between times being struck is very real. I'm getting more sound of fingers sliding on strings. I'm hearing nothing negative. My gear sounds very nice - I was playing Mark Knopler's "Dream of the Drowned Submariner" and it brought tears to my wife's eyes (a clear indication of success). I agree with @Gardenstater when he speculated about how many more speakers Polk would have sold had they sounded like this. That said, they would have sold at a much higher price point relative to the input of materials and labor. If you have the old (65XX) drivers I would definitely add these phase plugs and the @Gardenstater inner driver basket foam mod to the "must do" list. With the right mods these old speakers perform.

    c479jbtkh3i4.jpg
    Polk Audio first generation RTA-12s; 12 inch Polk Stands; DHS Speaker Service upgraded crossovers w/ Sonicap/Mills; the "westmassguy anti-lobing mod" (hyperdamped outer drivers/mirror imaged); tweeter anti-diffraction mod; Cardas binding posts; Neotech UPOCC internal wire; foam-lined inner driver baskets; xschop phase plugs; deleted fuses; Hurricane nuts; Sonic Barrier; Dynamat Xtreme
    Ayre K-5xeMP preamplifier
    Cambridge Audio 840C CD player; Herbie's Audio Lab Super Black Hole CD Mat
    D-Sonic Custom Audio M3a-600M monoblock amplifiers
    NAD 4155 FM/AM tuner
    Silnote Audio Morpheus Reference II Series II balanced interconnects; Virtue Audio single-ended interconnects
    Kimber 12TC speaker cable w/Furez connectors; VH Audio Flavor 4 power cables w/Furutech connectors
    Herbie's Audio Lab system isolation: Tenderfeet, Big Fat Dots, Grungebuster Dots, Little Fat Gliders
    Dedicated 20A/10 AWG circuit; Furutech GTX-D (G) outlet; Furutech eTP80; Shunyata Research Venom Defender; Synergistic Research Orange fuses