Monitor 7 / Model 7 Factory 2nd's ??

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13

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  • LilPolker
    LilPolker Posts: 40
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    I may just run them and not even epoxy them as they seem to have survived the 40+ years without the adhesive degrading (noticeably anyway...)
  • LilPolker
    LilPolker Posts: 40
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    Here is the first attempt to get the MW hole on speaker 1 of 2 fixed. 1/4" dowel and Titebond Premium II.sqkd7ny4vfam.jpg
  • F1nut
    F1nut Posts: 49,911
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    LilPolker wrote: »
    I may just run them and not even epoxy them as they seem to have survived the 40+ years without the adhesive degrading (noticeably anyway...)

    Ah no! Glue those magnets.
    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

  • Toolfan66
    Toolfan66 Posts: 16,981
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    Glue the magnets, you already have them out..
  • odcics2
    odcics2 Posts: 312
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    What they said.
  • LilPolker
    LilPolker Posts: 40
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    I like that song, Stevie Nicks and Lindsey Buckingham sang background vocals on the record.. Didn't see them on that video though...
  • LilPolker
    LilPolker Posts: 40
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    OT, MW bolt circle diameter...I am measuring 6.125" , can someone confirm?
  • LilPolker
    LilPolker Posts: 40
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    I'm curious. What is the diameter of the baffle circle cutout on those speakers. Did they make it too large where the screw holes missed? Should be fairly small clearance to the basket spokes and a round hole. I was sure they had used CNC machining but who knows?

    George, looking more into the hole drilling at the factory, is looking more like "Drill-N-C" as in Drill and See if it fits... LOL

    I am trying to repair/ adjust the BC for the MW and now measuring 6.125" for the MW driver...thinking this is a standard dimension for 6.5" drivers.

  • xschop
    xschop Posts: 4,759
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    LilPolker wrote: »
    OT, MW bolt circle diameter...I am measuring 6.125" , can someone confirm?

    I averaged all the ones I measured at 6.15" PCD
    You should consider drilling the 4 extra mount holes and get superior sealing and baffle coupling...

    https://forum.polkaudio.com/discussion/196649/mw65xx-drilling-jig
    Don't take experimental gene therapies from known eugenicists.
  • LilPolker
    LilPolker Posts: 40
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    xschop wrote: »
    LilPolker wrote: »
    OT, MW bolt circle diameter...I am measuring 6.125" , can someone confirm?

    I averaged all the ones I measured at 6.15" PCD
    You should consider drilling the 4 extra mount holes and get superior sealing and baffle coupling...

    https://forum.polkaudio.com/discussion/196649/mw65xx-drilling-jig

    Thanks

    Do some of these Monitor series use recessed mounting? I've seen some with flush/recessed mounted drivers. When did they change them?... I have surface mounted drivers
  • LilPolker
    LilPolker Posts: 40
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    ...also my silver baskets only have 4 holes, are you guys drilling these out to get the extra 4?
  • F1nut
    F1nut Posts: 49,911
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    LilPolker wrote: »
    ...also my silver baskets only have 4 holes, are you guys drilling these out to get the extra 4?

    It's a 6 inch driver, you don't need 8 freaking mounting screws.
    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: 4,759
    edited March 2023
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    If you add a dowel front to back between MW and PR and drill the 4 extra holes, you'd effectively remove all the front baffle flex.
    This translates to better midrange and bass output.
    But some like their flabby low-end response too.
    Don't take experimental gene therapies from known eugenicists.
  • F1nut
    F1nut Posts: 49,911
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    There's nothing flabby about the Monitor 7's bass.
    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

  • odcics2
    odcics2 Posts: 312
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    F1nut wrote: »
    There's nothing flabby about the Monitor 7's bass.

    No, there is not!
  • Gardenstater
    Gardenstater Posts: 4,214
    edited March 2023
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    xschop wrote: »
    If you add a dowel front to back between MW and PR and drill the 4 extra holes, you'd effectively remove all the front baffle flex.
    This translates to better midrange and bass output.
    But some like their flabby low-end response too.

    Yes, and @joebass3 has done it (2 dowels between passive and MW, front to back) and had a positive experience.

    Those of us who have installed your semi-rings made out of 1/4" steel and glued in behind the MW drivers have also experienced that bass slam improvement.

    It is all incremental and maybe ignorance is bliss?
    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
  • xschop
    xschop Posts: 4,759
    edited March 2023
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    Some people still listen to SL1000/2000's and only have that as a baseline for good vintage Polk sound.
    Until you do the mod, then you don't know what the improvement sounds like.
    Just the dowel alone tightens the bass response. The extra four fasteners is extra-credit.

    It's akin to Larry Holmes thinking he's not flabby and then get's schooled by the upgraded Tyson.
    Don't take experimental gene therapies from known eugenicists.
  • LilPolker
    LilPolker Posts: 40
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    OK, I get increasing fasteners to get better sealing, but still not certain if xschop was saying to do that to both MW and PR?

    Three things I would like info on:
    1- The question above to xschop
    2 - Did Polk change from surface mount drivers to recessed mount at some point? (mine are surface mount)
    3- What are you guys using to seal the drivers if the original seals are not reusable?
  • Gardenstater
    Gardenstater Posts: 4,214
    edited March 2023
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    As far as 2) goes, I am not sure of the exact date but with the Monitor 7B sometime after I bought mine in 1979 with the silver basket MWs and possibly shortly after, they had to put their own design of tweeter in called the SL1000 because Peerless stopped manufacturing the KO10DT tweeter in early 1983, they recessed the Passive Radiator only. I know this because @benjaminlea has 7Bs that had the SL1000 (however he reverted to Peerless) and he has black basket MW and Passive Radiator and only his PR is recessed. Then of course, at some later date, I don't know if it was when they went to the 7C designation or not, they were then recessing both the MW and the PR.

    The passive radiator already had 8 holes so I think it is a no brainer to drill 4 more holes and install screws there. The steel is thin and flexible. 8 screws clamps it better to the baffle, therefore they both become more of a unit, combining their rigidity into a greater amount. Doing the same to the MW is not so easy and requires a jig really, to do it correctly, and Rob has made one for himself and also sent me one but I've been procrastinating without any good excuse except for lots of distractions. The principle is the same there.
    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
  • mhardy6647
    mhardy6647 Posts: 33,183
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    The KO10DT tweeter was available into the early 1990s.
  • Gardenstater
    Gardenstater Posts: 4,214
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    For the seals, I have not had to replace any of mine but Rob has had good luck using 2mm EVA foam from Hobby Lobby. It comes in a sheet and he has been cutting it out as a one piece ring and gluing it to the MW flange.
    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
  • joebass3
    joebass3 Posts: 267
    edited March 2023
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    xschop wrote: »
    Just the dowel alone tightens the bass response. The extra four fasteners is extra-credit.

    The bracing I did along with your semi rings made a HUGE difference! Is having 8 screws in a 6" speaker overkill or would it improve performance even more? Personally I'd pass because I just wouldn't like the look, but since the OP has some screw holes that are already damaged it may make sense for him.

    Post edited by joebass3 on
  • xschop
    xschop Posts: 4,759
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    My 5Bs had all 3. I hate packing them up this weekend for garage construction, but out in large living room, the dynamics and impact was incredible. I would not trade them for anything their size. Sorry butt the R200's wouldn't sway me.They are excellent if you like listening to wind chimes.
    Don't take experimental gene therapies from known eugenicists.
  • Gardenstater
    Gardenstater Posts: 4,214
    edited March 2023
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    mhardy6647 wrote: »
    The KO10DT tweeter was available into the early 1990s.

    I have not seen one to date over 3 years of looking on eBay, with a date code after early 1983. Coincidentally (?) that is also about when Polk made the SL1000 as a substitute and a warranty replacement for the Peerless they had installed in speakers made by them before then.
    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
  • LilPolker
    LilPolker Posts: 40
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    joebass3 wrote: »
    ...but since the OP has some screw holes that are already damaged it may make sense for him.

    I repaired one of the holes on one baffle, the other looks like the bolt circle is offset away from the missed hole, so I may have to do a little more work on that one. I'm probably going to use a threaded insert once I get these holes in a good spot, possibly going with a riv-nut (since I have them). I think I saw people using the hurricane nuts, but size 10-24? Is that what size fastener is commonly used? A 10-24 riv-net has an OD approx .270 and has a small shoulder, I'd probably epoxy them in. Looks feasible to me. So yeah one baffle is pretty good (acceptable) now, the other, needs some attention.
    Thanks for all of your comments / suggestions!

  • Gardenstater
    Gardenstater Posts: 4,214
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    #8-32 screws are what everyone uses. If you go with hurricane nuts and glue them in, you would have a hard time putting semi-rings in at a later date.........just sayin' ;)
    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
  • joebass3
    joebass3 Posts: 267
    edited March 2023
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    LilPolker wrote: »
    joebass3 wrote: »
    ...but since the OP has some screw holes that are already damaged it may make sense for him.

    I repaired one of the holes on one baffle, the other looks like the bolt circle is offset away from the missed hole, so I may have to do a little more work on that one. I'm probably going to use a threaded insert once I get these holes in a good spot, possibly going with a riv-nut (since I have them). I think I saw people using the hurricane nuts, but size 10-24? Is that what size fastener is commonly used? A 10-24 riv-net has an OD approx .270 and has a small shoulder, I'd probably epoxy them in. Looks feasible to me. So yeah one baffle is pretty good (acceptable) now, the other, needs some attention.
    Thanks for all of your comments / suggestions!

    I used Rob's semi rings for the MW's but on the passive radiators and Peerless tweeters I used 8-32 hurricane nuts and drilled 7/32" holes. No epoxy needed.
  • F1nut
    F1nut Posts: 49,911
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    What are you guys using to seal the drivers if the original seals are not reusable?
    The popular choice has been Armacell. Parts Express sells a driver gasket material specifically designed for said purpose.
    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

  • LilPolker
    LilPolker Posts: 40
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    Have not posted in a while, was enjoying my Monitor 7's and really love 'em. I have a quick question about wiring the MW...I marked White and Black on the basket to assure I was installing them the same way they came out. That being said, I was playing around with a JBL 2600 MW which was a surprisingly good substitute... anyway I put that aside and went to put the Polk MW back in and was surprised to see that both of my M7's have the black wire going to the red terminal on the MW. Is this correct? I am 100% positive that I marked them correctly, but never noticed the red paint mark, to which I would have normally put the white on that terminal. I don't know if there is a schematic on the forum, but a quick answer from the experts is certainly appreciated...thanks in advance!