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Thread: Sinking Soundboards Revisited

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    Default Sinking Soundboards Revisited

    Hi, Im a new member. Im a guitarist whose son is a mandolinist. Being quite handy, my basic guitar luthiery has carried over into a 1919 Gibson Model A mandolin whose soundboard is sinking. The epicenter of this crater is approximately under the pedestal on the treble side of the bridge. Ive spent hours researching this phenomenon. Ive also read a number of threads on the subject here at the caf so I thought Id share my findings/opinions with the members.

    Short of removing the back of the mandolin, I felt that a support post just might help. However, the collective opinion is that nothing you can do to an old Gibson will support the sinkhole without affecting the tone. Yet, I feel that the tone is already compromised because you now have a concave depression adjacent to the sound hole on an otherwise convex soundboard. Worse, this instrument is more difficult to tune because the sinkhole lacks a ground zero and behaves like a trampoline or a cheap guitar tremolo. I felt I had nothing to lose.

    I decided to try installing a support post through the sound hole. This is like asking a proctologist to diagnose a sore throat from his end. It took me about two hours to brainstorm and make the homemade tools I would need and about fifteen seconds to put the post in place once the tools were built. The post consists of an approximate 2 length of dowel with a square cap and pedestal made of 1/8 plywood. The end caps were attached to the dowel using a short brad, into pre-drilled holes. I allowed some flex here so that the end caps could self-level against the top and back of the mandolin. No glue was used.

    Once in place near, but not under the bridge, the first thing I noticed was the ease of restringing. Once all the strings were installed, tuning was a snap. Also, the action height was not affected. Once I set the action using just the outermost strings, the rest of the strings obediently fell into place. The next thing I noticed was that the mandolin sounded louder and its sustain seemed unaffected. Im certain that me ear is not as finely attuned to subtle tonal variations as the rank and file here in the caf but I deserve some credit following more than a half century of guitar playing.

    The final test will be when my son returns from Argentina, sometime next year. Hes gigging down there with a different mandolin. He has the choice of leaving the post in place or removing it. No harm done.

  2. #2
    Moderator MikeEdgerton's Avatar
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    Default Re: Sinking Soundboards Revisited

    The post will affect the sound. Here's how Frank Ford fixed a similar problem.
    "Bargain instruments are no bargains if you can't play them". These are the words of J. Garber.

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    Default Re: Sinking Soundboards Revisited

    Quite a few years ago I had an "El-cheapo" mandolin and the top started to sag and I did much the same thing as you posted, I forced a dowel rod right under where the bridge sits and it made the mandolin sound 3 times better than it did when it was new....I have read on this Cafe where "sound posts" don`t do anything for a mandolin and they are for fiddles, not true, anyway it worked for me and sounds like it worked for you....As you stated no harm in trying some different things that are not normal...

    Willie

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    Moderator MikeEdgerton's Avatar
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    Default Re: Sinking Soundboards Revisited

    If that's the case Willie, why not put them in your good mandolins as they seem to improve the sound three times? I'd think that would be quite the incentive. I'm also shocked that none of the major builders have picked up this. I have no problem with alligator dentistry, I find it entertaining but I'm not buying this one.
    "Bargain instruments are no bargains if you can't play them". These are the words of J. Garber.

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    Default Re: Sinking Soundboards Revisited

    I`m not saying that is the way mandolins should be built, I am saying that in my case on an "El-cheapo mandolin it helped cure the problem...It is said that sound is better when there is more vibrations and just maybe having a post will help the vibrations be more evenly passed along from the top to the back...I am not a sound engineer and don`t know the ins and outs of all of that...ARE YOU?

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    Default Re: Sinking Soundboards Revisited

    Also Mike if you want to call me a liar because it is something that YOU can`t believe how about doing it with a PM and not posting it here for all to see...I have read a lot of your comments on here and find some to be quite interesting but others are put downs just like you did to me on the one above...I guess a moderator can do as he pleases on here but others are held to strict rules...I know I am not the first person to find your comments harsh......

    Willie

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    Moderator MikeEdgerton's Avatar
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    Default Re: Sinking Soundboards Revisited

    I have read on this Cafe where "sound posts" don`t do anything for a mandolin and they are for fiddles, not true...

    I didn't call you a liar, you have your opinion and all of us have those. Are you saying all the luthiers that have explained this before are liars? I don't think so. I just don't buy that it's going to improve the sound of any instrument. If you start with an unplayable instrument and it makes it playable that's great. The OP has what was once a decent instrument that could be repaired and probably sound as good as it did new. Simply discounting every luthier that has ever explained why sound posts don't work because you found it fixed your "el-cheapo" mandolin isn't anything other than your opinion. As far as PM's go Willie, I'm pretty transparent. If I disagree with something your telling a new poster I'm going to say something.
    "Bargain instruments are no bargains if you can't play them". These are the words of J. Garber.

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    Registered User Ivan Kelsall's Avatar
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    Default Re: Sinking Soundboards Revisited

    From Mike E - "If I disagree with something you're telling a new poster, I'm going to say something." Quite correct. After all it is only your 'opinion',not the gospel truth. However i do understand Willie's ire. If somebody has experienced an ''experience'' where they or others heard /saw something strange,then folks who weren't there should be careful not to offend with their remarks,purely out of politeness - & i am NOT pointing the finger at you Mike,that's for 'general consumption', including myself when i feel like being a tad antsy.
    Too many times on here i've read really nasty put-downs of folks opinions,fortunately,many of the offenders have 'left' !.

    If i disbelieve something that sounds improbable,i'll give a reason (opinion). The number of times folk have posted regarding their mandolins 'opening up',only to be almost laughed at because those folk haven't heard it in their own mandolins has been numerous. What right have we to say that it 'didn't happen' ?. We can express reasons why we think it didn't happen,but we weren't actually there were we ?.

    As we know all mandolins are different & some might respond to 'certain things' more than others. I can understand that in Willie's case,the mandolin he's talking about was maybe so bad that doing 'anything' to it could only make it better. I remember stating that adding a cast tailpiece to my own first 'el cheapo' mandolin improved the sustain & got laughed off. But i'd been playing musical instruments long enough to know what i heard.

    So,whether as in Mike's words' - 'we don't buy it' when somebody states that 'something happened',we shouldn't be too quick to dismiss them either. Tolerance is all,
    Ivan
    Weber F-5 'Fern'.
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    Professional Cat Herder Phil Vinyard's Avatar
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    Default Re: Sinking Soundboards Revisited

    Let'e pull this post back around! Here we go!

    Had the same problem on my 1921 Gibson, only on the bass side. Shortly after I got it I took it to my favorite luthier, Matt Harmon, at Mass Street Music in Lawrence, KS. He looked inside and saw that the bracing was loose, so he took it for a while and re-glued them. That stabilized it.

    I later showed it to Dave Harvey from Gibson. He commented that during that era, they just planed the tops a little too thin and having them drop was not unusual. His advice was as long as it was stable and playable, leave well enough alone and play it. He suggested a different bridge, but I decided to keep the aluminum bridge that was original to it. I later took it back to Matt Harmon and he refretted it, and it's one of my favorite mandolins. It has a good, deep tone and, with new frets, plays easily.

    I'm glad the sound post worked for you. It's one of those "If it works, great!" situations. You can at least play and enjoy it for a while. The alternative is for it to be a wall decoration, and that's a sad fate for a survivor of that many years.
    Phil Vinyard
    Gibson Jam Master F Standard #12 May 13, 2009
    Gibson Model A #67336 ca. 1921
    Trinity College TM-325 Octave Mandolin
    Freshwater Mandocello

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    Registered User Polecat's Avatar
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    Default Re: Sinking Soundboards Revisited

    My Vanden oval hole A started to sag several years ago (it was one of the first Mike Vanden built, around 1986, and I believe others have had similar problems with his early models). I took it to a reputable luthier who tried a minimal-invasive repair similar to Frank Ford's, as linked in Mike Edgerton's first posting. Cost a lot of money and failed after a relatively short time, leaving the problem worse than before. A while later I "gave" it to an acquaintance who builds and repairs guitars as a hobby; on my suggestion he removed the back, carved a new brace and glued everything back together. The instrument is now 100% stable, approx. 3/32" thinner than it was, and although I can't say for certain (it was out of action for about 5 years, and my memory for tone isn't that great over such a long period), I believe it sounds as good as it ever did. On seeing how delighted I was with his repair, the acquaintance "gave" me the mandolin back, and I "gave" him a fraction of what the reputable luthier demanded - at present it is my main axe.
    "Give me a mandolin and I'll play you rock 'n' roll" (Keith Moon)

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    Default Re: Sinking Soundboards Revisited

    Phil, Let also add that that "el-Cheapo" did not become a wall hanger, a fellow that played in a local band loved the sound of it after the sound post was installed and made me an offer for it that i couldn`t refuse and he is still playing it to this day and it was a good 40 years ago that he bought it from me...

    And to you Mike E...You say you didn`t say you called me a liar, what else could "I can`t buy this one" mean...It means to me that you don`t believe me...If you meant anything else I`m waiting for you to explain just what you meant...I am not looking for or trying make myself sound like I know everything like some on here do...I just pass on some things that I have seen, heard and did myself in hopes that those little ditties will help someone with less knowledge...I am sorry that you feel that my mandolin didn`t sound any better but I did record some with it and on the same cassettes was a Gibson F-12 that I owned at the same time and nobody, I say nobody could tell the difference when they listened to the recordings, Now that is something else that you may "not buy" but it is the gospel truth, sadly all of those cassettes have been sold and are long gone now...

    I am not mad at anyone on here I just don`t like for someone that hasn`t been there to tell me what I did, seen, or heard wasn`t factual...Thanks for your support Ivan...

    Willie

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    Registered User Doug Edwards's Avatar
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    Default Re: Sinking Soundboards Revisited

    I had a customer bring me his flat top to repair. The top sank enough to where he'd pulled all but the first seven frets to prevent buzzing. He also tried a "sound post" that either from the string pressure, a blow to the instrument, or both had gone through the back of the mandolin. I passed.

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    Professional Cat Herder Phil Vinyard's Avatar
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    Default Re: Sinking Soundboards Revisited

    By "wall hanger" I meant leaving it unrepaired and unplayable--what I was afraid would happen to mine. You did the right thing and did all you could, and I'm pleased it worked for you! I've played 'cello forever which works quite fine with a sound post. Always kind of wondered why those didn't become standard in mandolins. But that kind of sound engineering is beyond my pay grade.
    Phil Vinyard
    Gibson Jam Master F Standard #12 May 13, 2009
    Gibson Model A #67336 ca. 1921
    Trinity College TM-325 Octave Mandolin
    Freshwater Mandocello

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    Default Re: Sinking Soundboards Revisited

    I am intrigued by all this, and may one-day need to seek luthier help to undo top sinkage in a superb old A2 I have, its top slump is stable and has been for years, so I will not seek remedial action unless problem becomes unstable.

    I now refer to an earlier posted mention of Frank Ford's remedial method, sought out Ford's website and observed at point #4:
    "After swabbing the inside of the top with a rag saturated in hot water, I cranked the jack to restore the top to its correct form. I left the jack in place for a week, and after I took it out the top remained in good shape."

    I am curious about the effect of the hot water swabbing on the instruments top and jacking process, can anybody offer comments concerning possible adverse effects of the swabbing and or jacking up of the top-board following a swab, sadly I am ignorant of the ways of luthiery but would appreciate the opinions of those practicing the fine art, especially those who have actually tried Mr. Ford's approach

    PS: in regards to online bullying, passive aggression and or the perception thereof, good folk -please chill out, this is a co-operative forum for ideas, it is a drag to have to wade through online squabbles (more and more frequent at this site...) Please use simple placation or courtesy if posting a contrary opinion or advice, and for recipients of negative comments please remember the relevant schoolyard saying: "Sticks and stones... etc". Be kind, we are only here for a short time and have much to do.

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    Registered User Tavy's Avatar
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    Default Re: Sinking Soundboards Revisited

    Quote Originally Posted by Gop View Post
    I am intrigued by all this, and may one-day need to seek luthier help to undo top sinkage in a superb old A2 I have, its top slump is stable and has been for years, so I will not seek remedial action unless problem becomes unstable.

    I now refer to an earlier posted mention of Frank Ford's remedial method, sought out Ford's website and observed at point #4:
    "After swabbing the inside of the top with a rag saturated in hot water, I cranked the jack to restore the top to its correct form. I left the jack in place for a week, and after I took it out the top remained in good shape."
    The standard method for getting distorted spruce back to shape is a variation of Frank's method: press a damp cloth against the "underside" of the top, and then use a form to gently clamp it back to it's true shape. Once it's all dried out you're done. Just don't try to change the shape too much in one go or it'll crack. Works like a charm, but ideally you would reinforce the sunken area afterwards to prevent re-occurrence. For example, when repairing bowlbacks where sinkage around the soundhole is commonplace, I'll add two small longitudinal braces either side of the sound hole - these will keep the top straight and don't seem to effect the tone at all (cross-ways braces would be a different matter).

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    Default Re: Sinking Soundboards Revisited

    Hey Tavy, thank you for that really excellent description! Makes me way more confident of the validity of that whole approach. If I eventually need to go down that pathway or similar, I will need to consult with the acting luthier regarding appropriate additional bracing for a 1 piece carved top. My A2 is 1919 vintage and has an exquisite tone, it would be a terrible shame to lose that tone due to extra bracing. Then again it would be a greater shame to have a collapsed top due to insufficient bracing. Time for me to do some real fine monitoring of the top profile over time, to determine just how stable it is and whether or not to seek a remedy.

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