Mw6500, silver basket vs black

wispolkboy
wispolkboy Posts: 150
in Vintage Speakers
Is there a difference aside from the steel? Is one preferred over the other?
M7's 1982 Peerless tweeters
M5's X2 (1981 Peerless tweeters, 1988 with upgraded tweeters)
M4's X2 both with Peerless tweeters
M5Jr with SL1500 (in the garage, they sound great)
M4.6 series2 X2 with upgraded tweeters
SDA 2 with upgraded tweeters
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  • Gardenstater
    Gardenstater Posts: 4,468
    I have both but unfortunately I don't have the testing equipment (besides a multimeter) to check their TS Parameters. I will say that my 1990 NOS Made in Mexico black basket MW6500 has the windows located closer to the magnet and further from the surrounds.
    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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  • wispolkboy
    wispolkboy Posts: 150
    I have a couple of silver baskets coming in the mail... They are from a '79 m7. Also have the peerless, crossovers and pr coming as well... I guess that the cabinets were trashed.. Not sure if I will keep them as spare parts or build an exact copy of a m7. (no grilles)
    I was just curious about the 6500. Like if it was thicker steel or if they didn't have a magnet shift problem (i will jb weld them anyway)...
    M7's 1982 Peerless tweeters
    M5's X2 (1981 Peerless tweeters, 1988 with upgraded tweeters)
    M4's X2 both with Peerless tweeters
    M5Jr with SL1500 (in the garage, they sound great)
    M4.6 series2 X2 with upgraded tweeters
    SDA 2 with upgraded tweeters
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  • pitdogg2
    pitdogg2 Posts: 25,441
    edited July 2022
    All the older mw65xx drivers will magnet shift. I certainly wouldn't be too worried about them sounding different. They'll work just in the circuit they are designed for. According to @xschop the 6500 did have a narrower VC gap than the other MW65xx drivers. FWIW
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  • Gardenstater
    Gardenstater Posts: 4,468
    edited July 2022
    Oh congratulations. I posted that in the vintage deals thread the first morning it came up in my saved search. I wished I hadn't already bought others because those are a perfect match to my 79 speakers.

    I have disassembled the original silver baskets but I haven't taken apart any black basket ones I have which are later years. I would assume the magnet shift issue still exists with black baskets. I'm sure that it does in the silver baskets.

    Edit to add - I just checked my silvers and they are 0.039" thick. Checked one of my later blacks and it was 0.046". Also, my 1990 NOS black did not sound perfectly matched to a 1984 black basket nor my silver baskets. Sounds much better now with 2 1984 blacks that came in the same M4 speaker. I think there were variations in parameters over the years as the manufacturing locations shifted.
    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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  • wispolkboy
    wispolkboy Posts: 150
    I thank you for pointing me in the direction of those...😁
    M7's 1982 Peerless tweeters
    M5's X2 (1981 Peerless tweeters, 1988 with upgraded tweeters)
    M4's X2 both with Peerless tweeters
    M5Jr with SL1500 (in the garage, they sound great)
    M4.6 series2 X2 with upgraded tweeters
    SDA 2 with upgraded tweeters
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  • wispolkboy
    wispolkboy Posts: 150
    I ended up paying more than I wanted to for them... All of my vintage polks That have the 6500 are black metal... Do you want to do some type of swap?... Now they have not arrived and I won't be able to evaluate them for a couple of weeks because I will be out of town...
    M7's 1982 Peerless tweeters
    M5's X2 (1981 Peerless tweeters, 1988 with upgraded tweeters)
    M4's X2 both with Peerless tweeters
    M5Jr with SL1500 (in the garage, they sound great)
    M4.6 series2 X2 with upgraded tweeters
    SDA 2 with upgraded tweeters
    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,468
    edited July 2022
    Now that I have found out the blacks may be thicker metal I'm leaning towards keeping them and they sound great plus they are internal foamed, external dynamatted, and phase plugged and magnets glued. I'll keep it in mind and let you know thanks :)
    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
    · Share on FacebookShare on Twitter
  • wispolkboy
    wispolkboy Posts: 150
    Ok... What is phase plugged?
    M7's 1982 Peerless tweeters
    M5's X2 (1981 Peerless tweeters, 1988 with upgraded tweeters)
    M4's X2 both with Peerless tweeters
    M5Jr with SL1500 (in the garage, they sound great)
    M4.6 series2 X2 with upgraded tweeters
    SDA 2 with upgraded tweeters
    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,468
    edited July 2022
    wispolkboy wrote: »
    Ok... What is phase plugged?

    xschop's CNC billet aluminum phase plugs. Highly recommended. https://forum.polkaudio.com/discussion/190301/phase-plug-design-for-mw65xx/p1
    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
    · Share on FacebookShare on Twitter
  • dromunds
    dromunds Posts: 10,009
    Wispolkboy: if you are looking for a pair of Monitor 7’s I may sell a pair of mine and I’m in Wisconsin. PM me if you want to discuss.
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  • lawdogg
    lawdogg Posts: 455
    edited July 2022
    I have had both black basket and non-coated basket MW6500s to repair, so that means they both shift.

    I've actually, anecdotally anyway, observed wider VC gaps, or least wider VC-to-pole piece clearance, in the 6500s (with the felt dust caps) than the later drivers (with the mesh dust caps). (Which, for me, just means the 6500s are easier to re-center than the later drivers.)
    <3 my 3.1TLs

    I will fix your shifted magnets for free. :)
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  • Gardenstater
    Gardenstater Posts: 4,468
    edited July 2022
    My experience is that the VC to pole piece gap is very small on the silver basket 6500s that I own. We're talking about 0.0065" to 0.007" radial clearance. A 1.008" PVC plug gage I made is a nice slip fit into the VC ID and my pole pieces measure 0.9945" and 0.995" O.D.. I used 0.006" flexible plastic shims I made (with a built up layer to center the plug) to do Rob's phase plug mod on my black basket ones which I have not disassembled the magnets on, so I think the clearances are similar. Mine all have felt dust caps (1979, 1983, 1990). I haven't removed dust cap on 1990.

    Edit to add - just going by 0.006" shim drag or feel I would say the radial clearance of VC OD to framepiece ID on my 1979 silver baskets is even tighter. Probably 0.006" to 0.0065".
    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
    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: 5,000
    I believe I repaired the 'non-coated' 6500 and the VC gap was so small that it rubbed easily, even when flipped in the cabinet. I clearance it on the lathe with boring tool before gluing in new coil.
    Don't take experimental gene therapies from known eugenicists.
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  • lawdogg
    lawdogg Posts: 455
    That's really interesting.

    I'll pay more attention next time I do some - and maybe actually measure the pole piece OD and VC IDs.
    I'm sure I'll get the same results as you guys, I'm just surprised. I've never actually measured anything, I just know I curse a whole lot more when re-centering the later mesh-dust cap drivers than the 6500s.

    Have you all compiled any measurements across the various drivers? @xschop I know you had some great data when engineering your re-centering tools... I can take measurements of whatever comes in the door to re-center, maybe we can make some useful data out of it.
    <3 my 3.1TLs

    I will fix your shifted magnets for free. :)
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  • xschop
    xschop Posts: 5,000
    edited July 2022
    I posted exact dims somewhere here. Its the frame base plate thru-hole that is smaller on 6500 vs 6502, 6513/10 from what I measured.
    Maybe Polk sent out a warrantied version later on with wider gap?
    Don't take experimental gene therapies from known eugenicists.
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