Subwoofer Thump

Discussion in 'Speakers' started by Tommy Levario, Apr 30, 2006.

  1. Tommy Levario

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    This is a mystery to me. This problem seems to have appeared out of nowhere. My Paradigm Servo subwoofer has decided to make a thump sound for every time I switch (with or without remote) to a different input source on my RX V2200 reciever. This is especially annoying while navigating through DVD menus. I get a thump for every selection I make, except for the volume control. Heck, even the kids are yelling at me to make it stop.

    My first thought was that the connections may have come loose after so many years of the cool deep base, window shattering, rumbling but I've checked all the connections and re-tighten them but the problem persists.

    I'm thinking that this may not even be a speaker problem. Maybe I should be posting on the Reciever forums.

    If anyone has experienced this situation or has any clue whatsoever, please let me know. Thank you so much.
     
  2. Wayne A. Pflughaupt

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    The problem might be the Yamaha. I have one, and I get this sometimes when a DVD switches back and forth between regular and 5.1 signals i.e., like when you start the movie from the menu page (typically the sound on the menu page isn’t DD). On your receiver, see if you hear it when it’s switching between inputs with 5.1 digital, and inputs with regular analog connections

    Regards,
    Wayne A. Pflughaupt
     
  3. Tommy Levario

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    Thanks for the response Wayne.

    Yeah, I also get the thump when the DVD switches from 5.1 and regular signals.

    Did you replace your reciever or did you have it repaired or none of the above?

    The Yamaha cost me around $900 so, I'd hate to think that I need a new reciever. It's only 4 years old! Sounds like this could turn into a nightmare.
     
  4. Tommy Levario

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    Update:

    Some people were able to solve this same problem by changing the input settings on the reciever to "Digital" or "Analog" for each source. Apparently, if the reciever was set to "Auto", it caused the thumping / popping on the subwoofer / speakers. I checked the settings on my reciever but the only choices it gives are "Auto", "DTS", and "Analog". In any case, I tried all different combinations but no change.

    There are also some references to a "ground loop" problem between the reciever and the subwoofer. Some resolved this problem by using an AC adapter that allows a 3 prong grounded plug to connect to a 2 prong outlet or by using a ground loop isolator. I don't think this would help my situation because my subwoofer power cable already has two prongs and there is no a buzzing / humming noise emitted from the subwoofer (assuming that no buzzing / humming means no grounding problem).

    One post I read, indicated that a new and better subwoofer cable fixed the problem. I tried using a different cable but there was no change.

    There's no mention of this type of problem in the troubleshooting section of the manual so, no help there. However, based on my testing and some web research so far, it appears that it may be a bad "muting circuit", assuming that the Yamaha has one.

    To test this theory I removed all the connections from the reciever except for the power cable and the subwoofer connection. In fact, I used a new subwoofer cable for the connection and moved it across the room to reduce the chances of it being the same power circuit as the reciever. I still got the switching problem so I suspect this means that the reciever is indeed the culprit. Whether it is the "muting circuit" or not, I don't know.

    What do you guys think? Could it be anything else? If it is the muting circuit, any ideas on the $ for repair?

    Thanks again for any responses.
     
  5. Tommy Levario

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    Here's some additional information from my testing/research in case someone is formulating a solution.

    I checked the switch setting on the sub and I had it set to "Auto on/off". I changed it to "Always on" but it's still thumping.

    No problems with the amount of bass. Plenty there.

    It does not thump while the reciever is on and I change the input source on the reciever itself. It's a different story if I use the remote control. I think this happens because the remote turns off the when a different source is selected. I've also noticed that the thump occurs when I turn on/off the button. Not so much when I turn it off but I can still hear a soft thump.

    Not being well knowledged in the electrical field means that some of the post I've read are written in Greek . Nontheless, one post suggested that it could be a faulty transitor in the muting circuit of the reciever. I was hoping to go the DIY route but if its something like that, I'll probably have to take it in.

    Another post tried routing the LFE through the MAIN L/R speakers, and using the L/R pre-outs to drive the sub. Not sure if this would help or if it's even desirable. Would doing this help isolate the problem?
     
  6. andySu

    andySu Cinematographer

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    Tommy

    Hears what I would do.

    Firstly disconnect the sub bass RCA phone lead from the sub bass unit.

    Secondly if you have a spare amplifier around use it, use it for the amplifier source for the sub bass.

    Thirdly use a loudspeaker connected to the amplifier any loudspeaker will do, and connect the RCA phone lead from the LFE.1 to the amplifier.

    Fourthly set the volume on the amplifier at a low level.

    Fifthly do the same thing as you where doing, before with switching the settings around on the Yamaha etc, and see if this “thumbing” sound still exists, if it does then the Yamaha is in minor need for slight repair.

    Sixthly if there is no “thumping” sound, the subwoofer needs minor repair.

    I hope this solution we’ll help you out, into solving the funny?

    Good luck mate
     
  7. Tommy Levario

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    andySu,

    Thanks for your reply. Unfortunately, I don't own a external amplifier. I've thought about purchasing one but I haven't done any research on them. That's whole new topic. I'll check around. Maybe I can borrow one from someone. If not, I may dig in and buy one.

    I would be ecstactic if it turns out to be a "slight repair" or a "minor repair". Could this be a Do-it-yourself project?

    In case it's not, I sent out some feelers to get an idea on the costs involved. The authorized Yamy dealer (allegedly, the only one in the Asutin area! Hard to believe!) quoted me $65 just to look at the reciever and provide an estimate. I suppose that if it's a simple repair, it won't be much more than $80.

    Figures crossed.
     
  8. andySu

    andySu Cinematographer

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    Tommy

    I would get someone who’s not, not going to rip you mate as there are some out there who are pure scum and will take most for a ride.

    Find out from a repair dealer, what the fault is, and how much the components are going to set you back, and what the name of those components are that may have failed, 8/10 it’s relatively easy to “diy” just need a soldering iron and a little bit of good luck.
     
  9. Tommy Levario

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    Yeah, no kidding. I called Sears and they charge $32 to look at it but they have to ship it out to Tennessee for the repair itelf.
     
  10. Rajj Nair

    Rajj Nair Stunt Coordinator

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    hi tommy,
    i share this problem too.
    i hv a pioneer elite feeding into an amp the sub is fed direct from the receiver.
    this problem is only from the sub, each time i play stop forward or rewind my dvd player and its most irritating.
    i have 2 subs daisy chained and this comes on even when i tried attaching each, so im pretty convinced its not a sub problem.
    im going to try the digital setting you mentioned, and perhaps the 2-3 prong solution and let you know if that worked.
    else let me know if you have nay other ideas,
    thanks all,
     
  11. LanceJ

    LanceJ Producer

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    Hey Tommy: if you're main speakers don't have tiny woofers i.e. the 4 and 5 inch variety that could be easily damaged by low bass, to help eliminate the subwoofer as the problem (I personally do not think it is), change the receiver's speaker settings to "large front" and "no subwoofer". And for good measure, disconnect the subwoofer from the receiver's sub output.

    If you now hear that thump through the front mains, you found the problem. This statement especially makes me think its the receiver: "This is especially annoying while navigating through DVD menus." (if *software* is causing thumping........).

    The subwoofer's auto on/always-on circuit could also be misbehaving, and even if set to "always on", if it senses ANY tiny/slight variation in the signal from the receiver, it may think the receiver is being turned on or turned off. This is a long shot though and I still think the receiver is the problem.

    Good luck!
     
  12. mitch

    mitch Stunt Coordinator

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    Tommy,

    I had a similar problem a few years back with my Velodyne HGS-15 [also a servo sub]. I spoke to my Velodyne dealer and they told me that it was most likely the sub's amp. They told me how to remove the amp so I wouldn't have to lug the whole sub down to the store. I did that without any problem and brought just the amp in. They sent it away for repair to Velodyne and it was back totally repaired in 2 weeks. That did the trick! I would bet it's the sub amp.

    I hope that helps. Good luck!

    Mitch
     

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