GK Neo 112 ii rattling issue

Discussion in 'Amps and Cabs [BG]' started by StillBlessed, Nov 21, 2019.

  1. StillBlessed

    StillBlessed Gold Supporting Member

    Dec 20, 2010
    Hello fellow TBers. I am hoping that someone can shed some light on what may be going on what causing this rattling noise. I've read some threads about rattling on these cabs, but this seems to be different, or the information further confuses the issue for me.

    It sounds like a rattle/buzzing sound or like a speaker is loose or farting out. It only happens at volume and more easily when I play low on the 4th and 5th strings.
    When I put the cab on one side and put a weight on it, eg sit on it or put another cab or amp on it, the noise markedly lessens or pretty much stops.

    If I listen up close it seems to not be coming from the woofer, but the tweeter area. Not sure that would make sense since especially at that volume it seems to me the tweeter just stop playing by now. Yet, if I turn off the horn or put it in Bi-Amp mode there is no noise whatsoever. (I usually use a Genzler Magellan MG800)

    I also tried testing with a frequency noise generator and the rattling seems most apparent around 62hz and 124hz and again it seemed to be coming from the horn. This translates to what happens when i play "B" or close on the 4th and 5th strings; noise is most glaring but you can also hear it elsewhere on the lower strings. I tried adjust string height etc. Bass, Yamaha TRB-5 was also professionally setup by one of the best Luthiers in the Boston area, Steve Morrill.

    I called GK and described the issue to clarify how the crossover works and he agreed with me that the crossover shouldn't even be allowing signals to the horn below 2khz or 4khz ( I forget) and it's obviously not designed to play frequencies that low. Again there is not noise ever if I turn off or bypass the horn . Horn is the P-Audio PHT-406

    I already tried tightening all the screws I could find and removing the grill and nothing changed.

    Just redid this test today to make sure I am reporting the right result.
    I also had unscrewed the horn and rested it on a cushion away from the cab, but still connected, to try to isolate the noise. It was still making the noise.

    Also, does anyone know is there an upgrade to this horn as I may consider upgrading it whether or not it's a part of the problem. I prefer papercone to compression tweeters, but not sure if there is one that would be close enough to a direct replacement.
     
    Last edited: Nov 21, 2019
  2. Pulverizor

    Pulverizor

    Jun 14, 2018
    New Zealand
    Pulled the speaker out to check if the wiring isn't contacting anything?
     
  3. StillBlessed

    StillBlessed Gold Supporting Member

    Dec 20, 2010
    I don't think I pulled the woofer out to check for that specifically, just the horn, because it didn't make sense at the time, since the noise only happens when the horn is engaged.
    I'll still try that though.
     
  4. Pulverizor

    Pulverizor

    Jun 14, 2018
    New Zealand
    Apologies, I don't read good :drool:. Unscrew the horn and shake out the crap, if it's the bullet type they have little plastic dividers that can collect debris.
     
  5. StillBlessed

    StillBlessed Gold Supporting Member

    Dec 20, 2010
    I think I read somewhere that these horns are hard to unscrew. There appears to be some type of hard glue on the bolt when I checked. If memory serves, it also looked like it required some kind of non-standard tool. I remember reading a previous thread the where someone recommended a tool that can work. I'll check on that too.