replacement cone/coil kits for monitor 10, 6.5" mid/woofers?
Answers
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I have no idea what that is, but I'm sure it's a good thing.
Polk currently thinks so. From audioholics R700 review:
Getting into the bass drivers, the R700 uses two 8” polypropylene cones with some beefy half-roll surrounds that look like they could move plenty of air if given the opportunity. One interesting design detail about the bass drivers and midrange driver is that they use dual opposite-facing spiders so that any one-way bias in excursion by one spider is negated by the other spider. This should lower even-order harmonic distortions as well as do more to keep the voice coil aligned and restricted from lateral movements. The midrange and bass drivers also use shorting rings in order to reduce induction effects, which again broadens their bandwidth and reduces distortion.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 -
Nice! I'll have to buy some soon. Hoping to get to this over the winter. I admit, I'm still a bit intimidated by this project.
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Thanks for the details. I sorta get it now. LOL. While I love sound, and playing around with this stuff, the specs aren't really my strong suit.
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The wuhan MW coils have landed. These Spec'd out to 6.6 ohms each and fit the MW spud-jig perfectly, so no clearancing of the pole shaft its needed...
Don't take experimental gene therapies from known eugenicists. -
^^Nice! I'm curious about the height of the coil and how it compares. Also O.D.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 -
0.50" coil length
1.060" coil OD
1.40" total length
These would also work in and clear a factory 6500.
I really like the extra 4 holes for cooling too.Don't take experimental gene therapies from known eugenicists. -
Another problem I've found in some drivers is that the QC at Polk was iffy on some when they positioned and glued the VC's as their coil to base-plate depths are all over the place.
Every driver I've measured has a 0.23-0.25" thick baseplate so a 0.5" coil length should glue and set with 0.125" coil showing on the magnet side.Don't take experimental gene therapies from known eugenicists. -
Mine only show around 0.050" and to make them show 0.125" you have to push on the cone which results in the spider being visibly dished concave. That was a. ssembly error.
Not to mention the coils being cocked. I have to exert significant torque to make them perpendicular which also distorts the surround visibly in the process.
I'm putting in the warranty claim right now
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 -
Maybe better to post this here:
Just for the record, on my 1979 MW6500s I measure ID: slip fit to a 1.010 plug gage. OD: not round 1.057max, 1.054 min.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 -
This is sitting on one of the 2 alignment fixtures that I built. They will come in handy for voice coil replacements. I don't know how well these photos show it up but you can hopefully see that spider is noticeably dished. I'd have to do a video to show it but the front plate is very much not flat as well. I can spin the whole driver on the fixture and you can see that light shows at various changing locations between precisely machined brass standoffs and the front plate.
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 -
You'd be better off cutting the old coil out and replacing/re-setting with the newer one. Assuming your base-plate ID is @1.072 like the 6500's I've measured, you could possibly get away without clearancing the metal plate, but then you can still have more susp. sag over time and then you are back to same situation.Don't take experimental gene therapies from known eugenicists.
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Yep. I just ordered the last 2 coils on eBay. Not replacing the voice coils isn't an option with these drivers. The nice thing about it is, these are superfluous drivers and will a be a lot of fun to use as test beds for modifications such as sound absorption underneath spider, shorting rings, disassembly friendly motor design, etc..
PS: I really want to get ahold of the test equipment to do proper A/B measurements too. Listening tests are subjective and need to be backed up with something to at least show that it isn't a case of "destroying" your speakers lol.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 -
So, it's been quite a while since I posted on here, and I wish I was posting they are all fixed and working, but between being intimidated by the project, and life getting in the way, that isn't the case. I am, however, back to pondering them, and trying to work on them again. This is how far I got before feeling stuck.
The cone is out and in good shape for reuse, but not sure what to do about the spider. I was hoping to cut it out and reuse it, but can't seem to figure out a good way of going about it. I tried heating up the glue, but that did little to nothing. I tried getting in there with a razor, but it's pretty tight, and I don't see how I can get under the lip. The only other thing I can think to do, is cut them where they make the 90 degree bend and attach to the cage, and reconnecting them with a bead of glue around them in the 90 degree bend area. Is that what you guys do?
As far as I can tell, I don't think the magnet shifted, although I could be wrong. If you go back in the post, you can see how torn and burnt up the voice coil was, so obviously going to need new 1's. So far, I have only dissected this 1 speaker, but I have to do all 4 of them for my set of 10b's. Again, any help is greatly appreciated. I've been waiting many years, to finally get to hear these, but really didn't want to do any harm to them, either. -
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I don't know of anyone who has separated the spider to basket glue joint. If anybody has it would probably by xschop or lawdogg. I don't know for sure why you want to do it, but if you are certain you need to you could try a set of O Ring picks.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 -
If you want to see if the pole piece has shifted relative to the front plate, the way to do it would be with some flexible plastic shim stock. I found some houseplant plastic labels that were very flexible (Vigoro) that I got with some plants I bought from HD, that were about 0.007" thick. These happened to be about perfect for centering the voice coil on the pole piece in my case. You'd have to find what thickness you need for the gap between pole piece and front plate.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 -
Thanks man, from what I can tell, checking the way you described, the magnets are ok, But all the v.c.s are burnt up and pulled apart. I have since got them all to the progress of this 1 speaker. So far, so good, but 2 of the spiders did rip a little further out, due to more glue on them. So, 2 of them came apart easy and 2 of them I basically had to cut through them with my thumbnail, at the glue line, which left the center hole bigger and jagged. They can probably still be used, but the cone will have to go back in exactly as it came out, and I'll have to glue past where they ripped. Luckily, the above poster, link is still good for the v.c.'s but I'll have to contact the seller, and see if I can get 4 of them, since he only lists them in pairs, and is only showing 1 pair available. I need 4 of them.
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I have never separated the spider to basket. The couple voice coils I've done, I used ~26mm coils and did them with the cone & spider in place. I think one was a MW6500 and one was a MW6502 iirc. One worked with plenty of pole clearance but was SUPER tight to the basket, one rubbed against the basket. I haven't found a voice coil that is completely drop-in.
my 3.1TLs
I will fix your shifted magnets for free. -
Mine are the MW6503's. 2 of them were already coming apart, and needed to be reglued. Plus, I figured it would be easier to start at the beginning for lining things up, etc. But it doesn't look like I'll be removing the spiders unless I want to replace them.
