Polk Monitor 5B (MW6502) Sound Issue

minnesotawill
minnesotawill Posts: 6
in Vintage Speakers
Hi, all!

I got some great monitor 5s, but I noticed the sound out of one speaker is very quiet (though sounds not terrible). The mid on it isn't locked up, but I noticed there is a loose connection. Is this the culprit? How can I get it fixed?

The whole circled part moves in this one place. The other side does not.

o2q3ctx6xxok.jpg


Thanks!
· Share on FacebookShare on Twitter

Answers

  • F1nut
    F1nut Posts: 50,494
    edited March 27
    Is the faston moving or the tab? Is the tinsel wire from the voice coil to the tab still soldered to the tab?

    Generally speaking, when a vintage Polk speaker is quiet it is due to the tweeter not producing sound. Depending on the age/model it could be a bad fuse or a bad polyswitch issue.
    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

    · Share on FacebookShare on Twitter
  • minnesotawill
    minnesotawill Posts: 6
    F1nut wrote: »
    Is the faston moving or the tab? Is the tinsel wire from the voice coil to the tab still soldered to the tab?

    Generally speaking, when a vintage Polk speaker is quiet it is due to the tweeter not producing sound. Depending on the age/model it could be a bad fuse or a bad polyswitch issue.


    Bad with terms but the silver part that the faston connects to moves. The black part that the wire is soldered to the underside of does not. On the negative of this speaker and both connections on the other one, there is zero movement.
    · Share on FacebookShare on Twitter
  • minnesotawill
    minnesotawill Posts: 6
    The sound of the speaker is very much more in the highs and not the mids though so I figured it was the mid. Also, you could feel much less output putting your hand in front of the mid than on the other louder speaker mid.
    · Share on FacebookShare on Twitter
  • minnesotawill
    minnesotawill Posts: 6
    Here is a video: https://imgur.com/a/H3pz4fZ
    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,457
    edited March 28
    As long as the tinsel lead from the voice coil is still securely soldered to the + terminal and the faston is a clean and tight connection to the + terminal (check this and clean and close it tighter if need be), you will not have a problem that would result in decreased output. That terminal is probably glued to the black fiber piece which in turn is riveted to the steel basket. That glue probably broke and you could use a couple drops of super glue to secure it.

    You need to check polyswitches (temporarily jumper it out) or fuseblock (clean it) next, even though you are fairly certain it is a midrange deficiency because that midwoofer actually has output that goes pretty high, ie. 3kHz and cymbals fundamental tones are well within the midwoofer's output but there is a blending to the tweeter and it might be hard to tell which is getting the deficiency.

    After that, next in likelihood would be a rubbing or scraping voice coil. The glue in the magnet assembly doesn't hold up over time.
    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
    · Share on FacebookShare on Twitter
  • F1nut
    F1nut Posts: 50,494
    minnesotawill wrote: »
    Here is a video: https://imgur.com/a/H3pz4fZ

    That is not a problem.
    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

    · Share on FacebookShare on Twitter
  • joebass3
    joebass3 Posts: 283
    Time to break out the multi-meter and check the resistance on the driver.
    · Share on FacebookShare on Twitter
  • minnesotawill
    minnesotawill Posts: 6
    Thanks everyone. I ended up using auto setup on my receiver and now it is working fine. I did also glue the connection and swap drivers which isolated the one louder speaker to be a problem with the receiver.
    · Share on FacebookShare on Twitter
  • StantonZ
    StantonZ Posts: 444
    minnesotawill wrote: »
    I did also glue the connection and swap drivers which isolated the one louder speaker to be a problem with the receiver.
    Wow...didn't see that one coming (no kidding).
    Yamaha RX-A2050 AVR (5.0.2); LG OLED77C2 4K TV
    (4) Polk Monitor 10B's w/SoniCaps, Mills, and RDO-194 tweets (R/L F/R)
    (2) Polk RC80i (Top Middle)
    Polk CS300 center channel
    Analog: B&O TX2 Turntable, Nakamichi Cassette Deck 1
    Digital: Pioneer CLD-99 Elite LD, Panasonic DMP-UB900 UHD Blu-Ray
    Bedroom: Arylic Up2Stream AMPv3 driving Polk Monitor 4's w/peerless tweets
    · Share on FacebookShare on Twitter