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Rattle, Rattle, Rattle

Discussion in 'Amps and Cabs [BG]' started by BryanB, Jul 25, 2012.


  1. BryanB

    BryanB Moderator Staff Member Supporting Member

    I have a Fearful 15/6 built from lightweight composites by Art of Noise. I am powering it with a Fender TBP-1 and a Crown XLS 1500 in a rack case. The problem I have is that this cab vibrates quite a bit. I assume that is due to the light weight. So my amp rack rattles like crazy. I have tried a heavy anvil style case and an SKB case. I just get different types of rattles. Anyone have suggestions on how to prevent this annoyance?
     
  2. hdracer

    hdracer

    Feb 15, 2009
    Elk River, MN.
    Have you pulled a speaker and looked for a loose brace inside? I know they use a lot of bracing, maybe one came loose.
     
  3. BryanB

    BryanB Moderator Staff Member Supporting Member

    Yeah, I did that. Clearly there is an issue with the cab. It has its own rattle. I contacted Robbie about that. Are you suggesting the vibration level is not normal for this cab?
     
  4. hdracer

    hdracer

    Feb 15, 2009
    Elk River, MN.
    Sorry, I just noticed you said it was a composite cab. I only have experience with the plywood ones.

    Maybe get a friend to help you shake it to see if you can hear it when it isn't powered.
     
  5. seamonkey

    seamonkey

    Aug 6, 2004
    The cabinet shouldn't vibrate.

    You can read all about bracing
    http://www.audioholics.com/educatio...speaker-cabinet-bracing/conclusion-references

    But as the article concludes:

    "Simply adding more braces to a cabinet may not be the most effective way to reduce vibration if those braces are not stiff enough to force higher modal behavior in the panel under time varying loads, such as music."

    As pro builders on this forum have pointed out, this is a good way to brace, and it can be retrofitted to an existing cab.
    C86632BF-orig.
    Drill, and Stab the dowels through like swords.
     
  6. BryanB

    BryanB Moderator Staff Member Supporting Member

    Vibrates with certain notes, most noteably D0. It neighbors, C#0 and D#0, do not cause the vibration.
     
  7. rpsands

    rpsands

    Jul 6, 2007
    Phoenix, AZ
    Get yourself some recorded input and a cardboard paper toweltube to listen through, then localize the noise.

    Make sure the bottom of the cab has really good slightly soft rubber feet.
     
  8. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Third St. Cigar Records staff musician.
    Also, if you have spring loaded handles, check those too !
     
  9. BryanB

    BryanB Moderator Staff Member Supporting Member

    Any chance this is a defective speaker? If so, how would I check for that?
     
  10. rpsands

    rpsands

    Jul 6, 2007
    Phoenix, AZ
    It's improbable but possible. I'd check all the usual culprits first though, with the tube method.

    1. grill
    2. jack plates/handles
    3. speaker mounting (uneven, screws not tightened all the way)
    4. other crap in the room
    5. leaks in the cabinet
     
  11. No. If the cab vibrates, it's the cab. Simple. As noted already, it probably needs more bracing.
     
  12. barryaudio

    barryaudio

    Feb 9, 2012
    Massachusetts
    Authorized Builder: fEARful bass, greenboy designs, Bill Fitzmaurice
    Is the cab both vibrating and rattling? I mean if you take the head off of the cab, are you hearing some sort of rattle? If you are hearing rattle, something is loose. Most likely a screw that is holding on a handle, jack plate, or driver. If not rattle but the vibration is making your amp rattle, then there is mechanical coupling from the cab to your amp. Usually that is an indication that the panels are not stiff enough and need bracing.
     

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