Monitor 5B Hidden Gems
Answers
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Necessary is the mother of invention.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 -
Looks like those will need the spacer/washer behind the tweeter screws so the faceplace isn't distorted. I love my 5B's.
These were the burnt set I got from VSAT and rebuilt with aftermarket silk domes. These frames have been butyl-matted on the back sides. I believe that once they have been torqued down at the mount screws, those indentions are there to stay.
P.S. can someone please explain to Vanilla that I meant to say indentions, not intentions. Damn computers are getting dumber by the day.
I thought those tweeters looked familiar. lol. it took me another set of tweeters before I found the problem that toasted those. The B&K amp was oscillating at random times due to of all things a cold solder joint on one of the power supply boards. That is all fixed now and then some. I had a set of those speakers too. I liked them but someone else liked them much better than I. I cant believe how nice those are looking. Great job brother. I will stay tuned.
Oh, one more thing. No new real wood veneer for those ? Sure would look nice. -
I'm on the fence between a light wrinkle-black to match the factory baffle face material or go with Benjamin Moore's new Molten Metal series (It's trick)
The wrinkle-black looks great against the billet aluminum pieces going into the build.Don't take experimental gene therapies from known eugenicists. -
You can believe it or not but I have used satin rattle can spray paint to very good effect. Using the instructions it really did come out nice with the sanding and all. Please don't ask me where I got it because it is black and we will all be back on the longest thread in Club Polk history about "where do I get black paint" again ! :-)
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The billet RD0- tweeter project is finalized...I'll do the capacitor burn-in this week while I decide on what type of black finish to finalize the cabinets. Anybody else have this dilemma?
Also I used solid sheet 0.085" PVA foam to make new gaskets....
Don't take experimental gene therapies from known eugenicists. -
Sounds like a nice thickness. I might've gone thinner. I'm not sure what Polk used (or what its uncompressed thickness was) but it always seemed to me like it might be a polyethylene foam because it reminds me of the feel of the light grey pipe insulation (not the armacell). Where'd you obtain that PVA foam?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 -
The way you have those speakers bolted in there you could use just about anything and it would compress enough to seal them off. Very nice work @xschop .
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Gardenstater wrote: »Sounds like a nice thickness. I might've gone thinner. I'm not sure what Polk used (or what its uncompressed thickness was) but it always seemed to me like it might be a polyethylene foam because it reminds me of the feel of the light grey pipe insulation (not the armacell). Where'd you obtain that PVA foam?
I needed only 3 sheets from Hobby Lobby, as this is one of the standard stocked thicknesses.
I spent all my time at the pool this weekend to have any real listening time, but caps are being burned in at the moment. So far, they sound crystal clear and balanced.Don't take experimental gene therapies from known eugenicists. -
The way you have those speakers bolted in there you could use just about anything and it would compress enough to seal them off. Very nice work @xschop .
I'll be adding 4 more bolts to the MWs. Will tighten up baffle even more.... Working on the MW drilling prototype. Had my last set of 5Jr 6502s at shop to measure and trial fit. The inset plastic ring self-locates and prevents the butyl rubber surround from being torn while drilling. I drilled the new holes 0.190" because the factory holes are too large in the first place.
I used an exacto knife to clearance one of the rubber areas around the 8-32 dome head. I don't like having to still chisel the rubber off, so I'll just source Stainless mini washers for the dome heads....
Post edited by xschop onDon't take experimental gene therapies from known eugenicists. -
Can vintage Polks be brought fully into the 21st century? We're working on it. Reminds me of that movie I like Real Steel lol.
I personally swear by *these* under the screw heads. No more distortion of the basket flange and screws stay tight because gasket can be compressed more evenly. Will be much better with 8 screws and high end driver manufacturers do that even with diecast baskets, which are stiffer.
Post edited by Gardenstater onGeorge / 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 -
Anything you can do to tighten the driver coupling and increase baffle stiffness on these old codgers is a big improvement.
I'll be revisiting the cone and foam mod on the 5Jrs too.Don't take experimental gene therapies from known eugenicists. -
Agreed. I'm even thinking about some 3/4" oak dowel braces in my 7Bs and another thing I'm working 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 -
Left one is done. Every last tidbit of the MW flange vibration, especially between passive is gone.
Don't take experimental gene therapies from known eugenicists. -
I love it when a plan comes together (Lieutenant Colonel Hannibal Smith ca. 1983)
What about the passive radiator? Do you think that would be worthwhile?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 -
The passives were easy to do and they no longer vibrate at their flanges at 12,3,6, and 9 o'clock as high as my Onkyo can send juice. I simply burned the butyl rubber with soldering iron and installed hurricane nuts.
The passive will get its own backer ring when I get a chance. I wanted to put a torlon rod front to back, but the X-over sits centered at top of passive....
I found that if you burn the rubber, the surrounding rubber at the dome head wont deform or tear when torqued down. No washers needed...
Neighbors are happy my garage speaks are pounding 😆
The template works for marking and drilling the Midwoofer backer/brace rings. #29 drill used and 8-32 tap.
Don't take experimental gene therapies from known eugenicists. -
They are looking good man!
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Now that it is possible to do so, I think it would be interesting to see what happens to bass response if both the MW and passive are rotated 45 deg CW or CCW. Might give better response if more first reflections hit their mark on a passive window. Also might be more coherent.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 -
What are you **** into at the 3 and 9 o'clock positions as there is no backing plate there.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 -
Really!?! *S c r e w i n gPolitical 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 -
This website has cheat codes, it's really screwy...
8-32 Hurricane nuts. 3 and 9 o'clock have never been an issue with baffle flex on these monitors. The semi-rings stiffen baffle from left-to-right where problem occurs..
Lol, Zapp's Computer Love is rattling garage doors that are closed. Was playing my reference tune by Cameo, She's Strange. Baffle is almost rock solid now between MW and Passive.
MW and tweeter bridge is ROCK SOLID.
Gained another solid second on PR pushed test.Don't take experimental gene therapies from known eugenicists. -
Got it, thanks.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 -
From what I can tell, it looks like the PR was the culprit still expiring air too quickly on the push test when only 4 factory screws were installed ( I do have stiffer PVA foam installed on these)
I'll be building a set of larger/wider cabinet brace-backer plates for the PR's.
These are the dimensions needed for either a rectangle plate (can be made on hand mill) or radiused plate (CNC)...
These are based off an average of both my PR's bolt circle diameters of 7.82"
Post edited by xschop onDon't take experimental gene therapies from known eugenicists. -
Nice! I think we both had similar ideas in mind lol. I think 1.75" might even work, if you made the 0.55" dimension more like 0.302".
How do you make the 3.60" radius on the manual milling machine?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 -
The 0.55 dim. Leaves just enough clearance from my installed MW braces...
Radii are done on CNC. You can use dial calipers or DRO on a mill and just simply notch out the remainder once 3 holes are located and tapped.
This brace will be just as effective as a 3/4" dowel front to back, as it braces a wider span and reinforces the baffle bridge in conjunction with the PR flange coupling.
Don't take experimental gene therapies from known eugenicists. -
I have a spare 10" SW103 I measured at 9.715 PCD
Don't take experimental gene therapies from known eugenicists. -
^^ That would need a rectangular blank of flat stock steel measuring 8-7/8" x 2-1/4" to make a similar brace to your M5 brace design.
PS: By eye, with a tape measure, I get around 9-5/8" bolt circle on my 7Bs. That's measuring actual screw locations, not the holes in PR. Next time I have them on the operating table I'll try to measure accurately, even though I need a longer caliper.Post edited by Gardenstater onGeorge / 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 -
These worker bees have been through quite a bit last year and a half with all the mods and R&D. Even had a weed wacker fall and chip one on the work bench. Fixed it with DIY mix of belt sander dust and 2 part epoxy...
Road Warrior style will complete the look...
Don't take experimental gene therapies from known eugenicists. -
The polyurethane compound encases the exposed particle board ends that face the back very strongly. I can't chip it by fingernail now....
Don't take experimental gene therapies from known eugenicists. -
Bed liner, eh? Not a bad choice for shop 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 -
And....It's Black. Black paint. Where did you buy that ? Tee hee.
