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leslie 45 wood resonance causing buzzing, possible fixes?

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  • leslie 45 wood resonance causing buzzing, possible fixes?

    hello, i have a leslie 45 that i have been restoring over recent months, it looks great, but i have a problem with the wood resonating at certain frequencies. when the amp is turned loud, and i play certain low or high notes, the cabinet seems to resonate with the tone causing the cabinet to buzz and vibrate. i was wondering if it is generally considered ok to paint the interior of a leslie with a rubberized paint or something similar to help tame the resonance.

    any other suggestions??

    thank you,
    -Bryce

  • #2
    Dampening resonance this way will dampen music, too. Take a close look at he cainet's joinery etc, the problem is bound to be there. Put in ear plugs, jam a note down, and start pushing on things to see of you can stop it.

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    • #3
      likely loose wood as Wes says, cabinet braces etc. if not experiment with a little fiberglass dampening otherwise so you don't do any non-reversible work. Is the cabinet sitting square and level on a solid surface, on wheels or on carpet??
      1956 M3, 51 Leslie Young Chang spinet, Korg Krome and Kronos

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      • #4
        You could try stick-on automotive damping sheets. There are several brands. They usually have a rubber damping layer and a layer of metal. There are different thicknesses, maybe 50 to 100 thousandths. Try to get the butyl rubber, some other materials have a petroleum odor. There are precut square foot pieces that are convenient, and they can be easily cut to any size. Before you stick them on, make sure the metallic layer is not going to cause havoc with preamps or amps. I had piece too close to a preamplifier and it created a hum. They are very hard to remove once installed... almost permament. You can then cover these with stick-on felt if you want to. That should dampen any vibrating surfaces pretty well.

        But also make sure no panels are loose. Glue and nails and blocks glued in to corners can go a long way.
        1942 Hammond BC Organ
        Late 40's Hammond DR-20 Tone Cabinet
        1973 Leslie 122 Speaker (rumored to have been owned by Karen Carpenter)
        1905 Steinway Vertegrand piano
        1879 Steinway A Parlor Grand Piano Forte
        The only instrument I can play is the radio (But 4 years into piano lessons now!)

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        • #5
          I second the 'no' on the rubberized paint. Absolutely not. Check the back panel carefully and add extra felt as needed to make sure it's not rattling. Also check the veneer to make sure it hasn't come loose at the edges. Check the horn to make sure that it's not cracked and that the pins attaching the reflectors are not loose. Check the woofer and horn driver to make sure they're in good condition. Check to see that all screws are reasonably tight. Don't overtighten the woofer screws; you can bend the frame if you go overboard.

          I have a road warrior 147 cabinet that I rehabilitated. On it, I flowed fresh wood glue into all the joints wherever possible and had to reglue a number of spots where the veneer was loose. No more rattles.

          Finding cabinet rattles is a matter of patience investigation. Be glad it's not a Motion Sound cabinet. I've had to de-rattle several of those.
          I'm David. 'Dave' is someone else's name.

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          • #6
            I doubt one could hear a wood resonance on high powered and played tube Leslie 45, couldn't he?

            Anything in your room could resonate-like objects in the room or a tea spoon on top left of the console. But these a bottom tones.

            Saying that when turned and played loud, certain LOW OR HIGH notes make the cabinet to resonate with the tone causing the cabinet to buzz and vibrate could be a tired bass speaker and V21 in need of realignment.

            Could be a fallen spacer or bolt somewhere, or some wire that buzzes.

            I had once soldered a cap on my crossover with too long legs and its vibrations gave similar noises!

            I would only change wood glue joints if there are too dry and brittle, the leveling floor grommets and will check TUBES for microphonics, but never paint the inside of the compression box or even the wooden drum.

            This will kill the natural resonance of the wood by padding the little but important natural reverberation.

            Did you get the same effect with back open?
            Last edited by Guest; 05-20-2013, 06:03 AM.

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            • #7
              yes, same with the back open. im going to move it to a different room in the house to see if it responds to the same tones. also, it is on castor wheels not the metal sliders.

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              • #8
                Caster wheels themselves have been known to rattle.
                I'm David. 'Dave' is someone else's name.

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                • #9
                  Oh yeah!

                  Normal caster wheels are Normally lose.
                  I bet you'll have about the same buzz when trotter the Leslie around the house.

                  I had to install only twice two pairs of those for my trolley and it appeared that heavy duty wheels with bearings all around we're the best - at least don't buzz or rattle.

                  If back open doesn't change it, this may not be the wood resonance. But the other suspects remain on focus.
                  Last edited by Guest; 05-20-2013, 08:52 AM.

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                  • #10
                    Check out the sides of the bass rotor, they can vibrate, especially if there's no bolt running between them.
                    -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
                    -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
                    -DIY 760 FrankenLeslie/rat hideout-
                    -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
                    -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

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                    • #11
                      And check the balancing weights on the drum. I had a rattle in a 122 last week that turned out to be a nut that had come loose on one of these.
                      I'm David. 'Dave' is someone else's name.

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