Speaker Buzz HELP

Discussion in 'Cabinets & Speakers' started by michaeljeffrie, Feb 27, 2010.

  1. michaeljeffrie

    michaeljeffrie New Member

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    i recently purchased a marshall 1960 bv, loaded with the marshall g12's (V30's). it sounds AWESOME when in standard tuning. but any sort of drop tuning played at high volumes creates this loud speaker buzz/rattle. is there any way to fix this? i thought maybe something was loose, but like i said, no sort of buzzing is made in standard tuning at the same volume. i would really like to keep this cab because the tone is exactly what i'm looking for, but this buzzing is dreadful.

    any suggestions are much appreciated!
     
  2. 5er driver

    5er driver New Member

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    Check that the speaker nuts are tight, don't overtighten.
     
  3. clel miller

    clel miller New Member

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    Hard to say, could be a lot of things. But you say it does not happen in standard tuning when you play "bass" notes.....?
    I just went through this with a Eminence C-Rex in a Tweed Deluxe. It was the cone, no way to fix it other than recone the speaker. It was easy to diagnose because of the 1x12 cabinet.
    If the cab is new, you have a warranty, if it is used.......
    If you cannot find an answer you may want to get a pair of jumpers and just go speaker to speaker and see if you can find the offending driver(s).
    Good Luck
     
  4. michaeljeffrie

    michaeljeffrie New Member

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    yeah, like when i play an open e power chord, nothing happens, but when i tune to drop d....the bass note is extremely buzzy. what is this "jumper" you speak of? i also heard that it could have something to do with the "resonance" frequency of the cab, meaning that the actual frame of the cab can't handle such a low note. is there any truth to that?
     
  5. clel miller

    clel miller New Member

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    Yes, there is truth to that, almost. No doubt what was meant by "Resonant Frequency" was the frequency that will make the cab harmonize with the speakers. This "harmonizing" is heard as a buzz. This is one reason you read so much about speaker cabs being built from 13 ply "VOID-LESS" Baltic Birch. With no voids, gaps, knots, wholes, cracks, etc., there is less chance of the cab becoming resonant with a certain frequency.
    So what I am trying to say is, resonant frequency in a speaker cab, usually refers to a cab being noisy or buzzing when you play at a certain note, chord, octave, whatever. So yes, it is possible your cab might be doing this.
    What I was suggesting was isolating/disconnecting each one of your speakers from the jack and playing each one separately to see if one of your cones is bad at the certain note(s) you are playing.
    But I cannot hear what you are hearing. Maybe what you hear is much more of a cab resonating than a cone that is buzzing. Only you know that answer.
    Good Luck
     
  6. michaeljeffrie

    michaeljeffrie New Member

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    thanks for the response, that helped a lot! i'll do that tomorrow and see if the speakers are the problem. if not and it is the actual cabinet, is there a way to reduce the buzzing/correct this? i heard putting foam inside could help.
     
  7. michaeljeffrie

    michaeljeffrie New Member

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    to add to that, am i just better off selling this one and buying something that CAN handle those lower notes?

    (insert 4x12 suggestions here)
     
  8. MartyStrat54

    MartyStrat54 Well-Known Member

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    Ahh...I just want to say that the information in reference to the "resonant frequency" is not accurate. The resonant frequency is part of the Thiele and Small parameters relating to loudspeakers. It is called Fs and is measured in Hertz. All vibrating objects have a resonant frequency. In the case of a guitar speaker, when it hits its free air resonant frequency, the cone is undergoing maximum excursion, the back emf (electromotive force) is largest and the impedance highest. At resonant frequency, the impedance can be as high as 40 to 50 ohms on an 8 ohm speaker.

    The other statement I want to talk about is "a box." If you have a sealed, vented (ported), or open back cabinet, it too has a frequency that it will resonate at. In a well built cabinet, this is kept to a minimum. Guitar speakers are much different than bass or sub speakers. Bass cabs must be built properly, or the cab could come apart by the power and force of the bass or sub.

    All permanent cabs are built out of Medite or High Grade MDF. Portable gear is built out of 13, 15, or 17 ply, plywood and yes it is void free. Most cabinets today have an MDF baffle board and the box is built from the plywood. Most 412 cabs are not braced very good. If the resonant frequency of the box is close to the resonant frequency of the speakers, you are going to get some undesirable noise. Most guitar cabs are usually built with a lower Q, or resonance. By doing the drop tuning, your speakers are now going below Low E on a guitar which is 82.40Hz. A drop C is 65.40Hz. The cab could be resonating at this lower frequency. You may want to modify your back brace in the cab. They are on the cheesy side. Another member had a similar problem and he ended up getting the proper sized screwdriver and tightened the screws holding the baffle board to the cab and then carefully tightened the screws in the speakers using a "star" pattern.

    Since the cab doesn't have a problem tuned in Low E, I would have to point at the cab as the source of the noise. The speakers may be a little loose, but I suspect your cab is resonating because of the low tuning. Putting speaker filler in the cab is not going to do anything. You have got to stop, or greatly reduce what is vibrating in your cab. You may have to put in better bracing. Also, make sure your handles are not making the noise. Some guys put a gasket under the handle and the cab. This is sometimes a source of noise.

    I hope this helps.
     
  9. Ken

    Ken Well-Known Member

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    One lister said he had a handle vibrating. If you have a friend handy and a 3' piece of tubing, have the friend play the notes that cause the vibration, stick a finger in one ear (yours) and the tube in the other, and use the free end of the tube to place arond areas of the cabinet. The source of the sound is a lot easier to find this way. Could be the back, a handle, a speaker mount or even a shelving unit in the room next to your bottom (don't laugh; that happened to me!).

    Ken
     
  10. michaeljeffrie

    michaeljeffrie New Member

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    marty, i kinda-sorta got the jist of what you were saying, but i'm not exactly experienced with all this lingo. by bracing do you mean the back panel of the cab? or the piece of wood that runs horizontally in the inside?

    i hope this doesn't make me sound foolish.
     
  11. MartyStrat54

    MartyStrat54 Well-Known Member

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    Exactly. Low frequency equals power. If you got 65Hz at 112dB, it is moving the shit on your shelves and causing boards to moan and vibrate. So yes, you need to consider what else is in the room with the cab. Hell, over the years I have broken all sorts of stuff. Had a whiskey bottle come down, but that was from the loud bass player. I lost a damn near full quart (yeah back when liquor was still sold in quarts) of 101 Wild Turkey. The only whiskey I drank for close to 15 years.

    So that brings up the other question. How loud are you playing?
     
  12. michaeljeffrie

    michaeljeffrie New Member

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    i am playing a 100-watt all tube head with the volume around 6-7. so....VERY loud. but i don't think that is the problem, i have put my head up to the cab and i can hear something buzzing.
     
  13. MartyStrat54

    MartyStrat54 Well-Known Member

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    Yes, you want to check the back panel. Sometimes the screw that goes into the "post" is offset or not properly seated. Also, were the post is attached to the baffle board, it can be loose. Check the post for any problems. With the back off, wiggle it slightly and make sure it is pretty solid. It should move a little, but not a lot.

    Make sure the screws holding the baffle board to the cab are tight.

    Make sure all of the hardware is tight.

    Now you may have a loose dust cap on one of your speakers. You may have to pull them to check. However, it is a different kind of sound compared to something that is loose inside the cab.
     
  14. michaeljeffrie

    michaeljeffrie New Member

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    i checked the inside, the post IS loose. i think that might be the problem. from what i can see, the screw on the back panel was stuck in way to the right... how can i ensure it is centered after i put the back panel on? also, near the baffle board is incredibly wobbly too. i thought that two screws on each side at a 45 degree angle would work. suggestions?
     

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