Blown Speakers?

BruceS
BruceS Posts: 7
in Troubleshooting
Hello,

My Dad gifted me a pair of Monitor 10's in 1979 and, last month my wife inadvertently turned the volume on my amplifier to the maximum when dusting. Needless to say, when I turned on a CD the sound nearly split my eardrum as I immediately turned the volume down.

Unfortunately, the midrange speakers on one of the speaker cabinets only plays in the "high" range, and no bass is created by the ten inch passive radiator.

Reading a few posts advising that the midrange speakers can be simply unscrewed and the wires removed by pulling off the wire clips, I discovered that mine are soldered to the speakers.

My question is: Are the speakers blown, or could one of the electrical components connecting the speakers to the output posts have been damaged by the extreme volume? (Incredibly, the glass fuse to the tweeter did not blow.)

Thanks in advance for advice and assistance.

Bruce
· Share on FacebookShare on Twitter

Comments

  • Msabot1
    Msabot1 Posts: 2,098
    Your PR operates as a function of your mids....before taking anything apart...lightly push in on the driver in question...notice if there is resistance or a scratchy feel or noise...also notice the response of the second driver and PR...not a lot of pressure is needed to do this....this is an old home test....check the cone and surround for visible damage also....interesting that when you subjected those to max volume that you did not blow the external fuse....
    · Share on FacebookShare on Twitter
  • BruceS
    BruceS Posts: 7
    Thanks very much for the quick response, Msabot1, I'll give it the home test and let you know!

    Yes, the glass fuse not blowing amazed me, considering that I've blown it a few times in the past with far less volume than this time.

    Bruce
    · Share on FacebookShare on Twitter
  • BruceS
    BruceS Posts: 7
    Msabot1,

    Both of the midrange speakers are "tight as drum" when compared with the midranges on the undamaged speaker.

    Does this mean that the midranges are blown and need replacement?

    Bruce
    · Share on FacebookShare on Twitter
  • Msabot1
    Msabot1 Posts: 2,098
    Yea...sorry to say that it is a safe assumption that the voice coils in them are history....that is why you are not getting any response from your PR.....Replacements for those are easy to come by...Take them out...there should be model numbers and other info on the back of the magnets....call Polk with the info,and they will put you on the right path to getting replacements....You will get a discount too by mentioning that you are a member here...used to be easy before the forum changed...not so sure about it now...seems to be a problem with vintage support...maybe not though....By the way...I've had a pair of 10B's since I bought them new back in early 84....still some of my favs......next time make sure volume is set to zero...before engaging the source.....then gradually increase to your desired listening level......might save you a headache or two.....
    · Share on FacebookShare on Twitter
  • Msabot1
    Msabot1 Posts: 2,098
    One other item you might want to do....when you pull those drivers...look over the Xover board and components for anything that looks odd...burn marks...melt...anything that looks like it should not be there...wiring connections..since I'm assuming they are originals..might be a good idea before you get it all put back together and put the spurs to em....
    · Share on FacebookShare on Twitter
  • BruceS
    BruceS Posts: 7
    Great advice, and I thank you sincerely, Msabot1. I already checked the components visually and didn't see anything burnt or melted, but I'll double-check when I remove the drivers.

    Bruce
    · Share on FacebookShare on Twitter
  • Msabot1
    Msabot1 Posts: 2,098
    Cool....I'm no expert..but I know a little about how to keep things simple...you will learn tons from the folks here...good luck getting them back up and running....
    · Share on FacebookShare on Twitter
  • deronb1
    deronb1 Posts: 5,021
    Yup, voice coils. Just went through that nightmare myself. Smell them. They will have a distinct burnt odor.
    · Share on FacebookShare on Twitter
  • BruceS
    BruceS Posts: 7
    Thank you Msabot1 and deronb1...I really appreciate the advice!
    · Share on FacebookShare on Twitter
  • dbp
    dbp Posts: 12
    One of my midrange speakers in my 10Bs has a partially collapsed cone. Does that mean a problem? That 10B has for many years had fuzziness and scratchiness in the high end; I was assuming a tweeter problem, which is interesting considering that is the SL2000 that was replaced in 1994 after my purchase in 1987. Any ideas about how to test for tweeter versus midrange issues?
    · Share on FacebookShare on Twitter
  • dbp
    dbp Posts: 12
    I should have said collapsed dust cap over the voice coil, not "cone."
    · Share on FacebookShare on Twitter
  • gmfeld
    gmfeld Posts: 1
    edited April 2015
    I had the same situation as BruceS going from headphones at max volume to my Polk Monitor 4's. Could it be the fuses? What would blown fuses look like? I'm only getting muffled sound in the midrange. Nothing in the tweeters or bass.
    Post edited by gmfeld on
    · Share on FacebookShare on Twitter
  • tonyb
    tonyb Posts: 32,983
    Max volume ?? You don't see a problem with that ?
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
    · Share on FacebookShare on Twitter