Monitor 10 some questions

jct74_dk
jct74_dk Posts: 33
in Vintage Speakers
Hi

I just acquired a set of 10 series 2 speakers. In my opinion they sound really nice coupled to my British Alchemist Amp.

Since I am unfamiliar with Polk I wanted to ask some questions:

- is there a way to check the overall condition if the speakers are working properly?
- what would be the first sign of a bad crossover? Do I need to change any parts in advance?
- can I get replacement parts from Polk?
- is there something I could do to preserve them before anything goes wrong?

Thanks for any comments.

Kind regards JCT
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Comments

  • SeleniumFalcon
    SeleniumFalcon Posts: 3,761
    Hello JCT,
    Welcome to Polk's forum. Congratulations on getting a great example of one of Polk's most popular and well regarded speakers.
    In general terms most people begin examining a pair of speakers by simply listening to them on a wide variety of music. Listen for any obvious gaps in the sound spectrum, lack of treble or a flat quality to the sound. You can remove the dust covers and carefully cover the tweeter with a small pillow and more isolate the other components. Of course any distortion would be something to be concerned about.
    For the most part crossovers seldom develop problems, unlike powered components. There can be gains from improved parts substitution, as I'm sure others will point out.
    For the most part Polk no longer provides replacement parts for this series of speakers.
    The best way to preserve them is to not over drive whatever amplifier is powering them. Always use them so that distortion is kept to a minimum.
    Enjoy!
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  • xschop
    xschop Posts: 5,000
    edited January 21
    Searching here how to glue the midwoofer magnets should be top priority. Welcome aboard.
    Don't take experimental gene therapies from known eugenicists.
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  • jct74_dk
    jct74_dk Posts: 33
    Can I make a test to see if the woofers are working the way they should?
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  • SeleniumFalcon
    SeleniumFalcon Posts: 3,761
    Are you referring to the passive radiator or the 6.5" drivers?
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  • jct74_dk
    jct74_dk Posts: 33
    Actually both.
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  • Astrl55
    Astrl55 Posts: 64
    enter "push test" in the search box at the top of this page
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  • SeleniumFalcon
    SeleniumFalcon Posts: 3,761
    If you gently push on the 6.5" drivers making sure to keep the cone evenly moving forward and backward there shouldn't be any scraping or scratching sound. In order to examine the driver further you would need to remove them from the cabinet. Is this something you want to do?
    The bass radiator is moved by the pressure changes happening inside the enclosure caused by the two 6.5" drivers. They are very seldom damaged. You should see the passive radiator move outward when one of the drivers is gently pushed inward.
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  • jct74_dk
    jct74_dk Posts: 33
    Thanks for the guidance how to check the woofers.

    I will look for any scraping.

    Is it safe to remove the drivers just by unscrewing them and pulling them out? Can I damage the magnet and glue in some way?

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  • pitdogg2
    pitdogg2 Posts: 25,412
    They're safe to remove and look at. Be careful not to go to tight on the screw when putting the driver back on, it's easy to go for that last little turn and strip the screw hole.
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  • jct74_dk
    jct74_dk Posts: 33
    I realized I have some edge damages on the cabinets.

    Any suggestions how to restore the veneer?

    Thanks!
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  • jct74_dk
    jct74_dk Posts: 33
    I just did the pressure test.

    When pushing the midrange drivers the radiator moves outward. When pushing the radiator both the midrange drivers move outward.

    No scraping.

    So far so good.

    But when pushing and holding the radiator the midrange drivers retract almost immediately. If perfect they should retract after a couple of seconds.

    Is this a problem regarding air leak?

    I find the bass response good.

    Thanks!
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  • boston1450
    boston1450 Posts: 7,630
    edited March 16
    @jtc74_dk If, you push in on the passive & hold it in & the woofers go back to resting spot immediately you have a leak somewhere.. when you push in & hold - it should stay out for 3-5 seconds... Try LIGHTLY tightening up the screws on the woofer & passive & on the rear binder cup. Report back on what you find. Are the cabinet edges all good ? Sometimes I've seen some separate. You may have to go in & check gaskets on woofers & reseal the cabinets. While your at it you can Reglue the magnets by putting a bead on each side of the magnets - to help prevent magnet shifting... Look over your crossovers as well. Good luck
    ..
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  • jct74_dk
    jct74_dk Posts: 33
    How much pressure do I have to apply to the radiator? Just a light pressure? For how long time to I need to hold it in?

    Silly question but do I need to have the power on between amplifier and speaker?
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  • boston1450
    boston1450 Posts: 7,630
    Lightly press in & hold & count.
    ..
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  • boston1450
    boston1450 Posts: 7,630
    No. Keep unit off. Whenever you work on speakers keep unit off. Whenever you mess with RCA cables / patch cords shut unit off
    ..
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  • jct74_dk
    jct74_dk Posts: 33
    Okay thanks.

    I will post some pictures to let you see if everything seems alright.

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  • jct74_dk
    jct74_dk Posts: 33
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  • jct74_dk
    jct74_dk Posts: 33
    So here are some pics.

    When I took out the one driver the sealing came a little off.

    Otherwise I think they look decent both drivers and the cross over filter.

    Opinions?
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  • jct74_dk
    jct74_dk Posts: 33
    The one driver is apparently made in Mexico
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  • jct74_dk
    jct74_dk Posts: 33
    I did not bother opening the other speaker since I expect it to be similar to the one I opened.

    However I think they sound truly nice so if there is an air leak I guess I don't notice it.
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  • Gardenstater
    Gardenstater Posts: 4,457
    That gasket is damaged and was probably leaking. At some point Polk moved assembly to Mexico. I think it was Tijuana. You shouldn't have 6502s mixed with 6503s. That 6502 doesn't belong in your speakers and has an entirely different impedance, among other parameters that differ.
    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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  • jct74_dk
    jct74_dk Posts: 33
    Thanks.

    So what would you advise me to do?
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  • Gardenstater
    Gardenstater Posts: 4,457
    edited March 17
    jct74_dk wrote: »
    Thanks.

    So what would you advise me to do?

    Well, I would definitely first open up the other one to see what surprises may await you there, and see how many MW6503 you need to purchase on eBay. Sometimes you don't find them with a direct model search but if you locate a seller that parted out a SeriesII speaker you may find the drivers indirectly that way. You can also put in a saved search to be first at the grab when they pop up in the future.

    Gaskets gaskets. I prefer a very thin and soft material. I haven't had to replace any of mine. Rob (xschop) has used the EVA foam material available from Hobby Lobby. Cut out a ring of it and glue it to your driver. I've seen thin and soft stuff on rolls that is adhesive backed at Grainger, McMaster Carr, etc.. Many here (not me) will recommend 1/8" Armacell available from Home Depot if you are in the states.
    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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  • jct74_dk
    jct74_dk Posts: 33
    Okay thanks.

    In case the other speaker has the MW6503 would it be advisable to change the both drivers to have a matched pair?

    Can I leave the defective gasket for now or does it have an effect on the sound?

    I am outside the US.

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  • Gardenstater
    Gardenstater Posts: 4,457
    jct74_dk wrote: »
    Okay thanks.

    In case the other speaker has the MW6503 would it be advisable to change the both drivers to have a matched pair?

    Can I leave the defective gasket for now or does it have an effect on the sound?

    I am outside the US.

    Both drivers need to be matched for sure, and both need to be MW6503. You might be able to apply a little rubber cement to both the driver frame and gasket and stick that broken gasket back on, butted up at the break, and have it seal just fine. You'd have to judge if you think it is still serviceable.
    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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  • jct74_dk
    jct74_dk Posts: 33
    So worst case I need four new MW6503 to get them matched?

    You think I have to worry about air leak? The pressure test showed that the drivers didn't stay out long but retracted.

    They are not frozen in any way so I guess functional.

    Any idea how to repair the damaged edge on the one picture
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  • boston1450
    boston1450 Posts: 7,630
    naf4u8f4jcq4.png
    Is that a hole ?
    ..
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  • boston1450
    boston1450 Posts: 7,630
    That cabinet is spent
    ..
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  • jct74_dk
    jct74_dk Posts: 33
    It's should be an outside damage on the veneer. No hole in the cabinet.
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  • boston1450
    boston1450 Posts: 7,630
    It was quite the hit. Probably why the woofer was replaced. The seem appears to continue to the front as well
    ..
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