Annual Humidity post - SUPER IMPORTANT - READ THIS!!!!!!! (long, but worth it)

Put a plywood top on an Ovation back, and you can probably safely ignore humidity. The problem is you have an Ovation with a plywood top to play . . .

My gat is going through its annual sunken top syndrome, even though I have a house humidifier and I added a humidifier in the studio to help it out, until the humidity started causing other problems. It's a problem gat, but I lack the funds to have a real luthier fix it, and I lack the skilzors to fix myself. Beyond the top, the neck looks like a tilde . . . but it's a pretty guitar that sounds great . . . in the summertime :(
 
muttley600
So you are saying that the fact that many guitars react badly to changes in humidity is down to a lack of understanding of the way timber behaves under such changes? The fact that luthiers don't understand these changes? That all guitars that manifest problems as a result of humidity changes are a result of "poor craftsmanship?
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Throughout the 19th century, well-to-do Americans would buy furniture from the finest craftsmen in Europe and have it shipped to their New World estates. For those who lived East of Chicago this represented a symbol of their wealth and prosperity. Unfortunately, when the wealthy of the West tried to do the same thing they ended up with furniture that split from checking, misfit pannels, non-functional doors and drawers, and tennon joints that failed to hold the furniture together. Mind you, these items were made by the most notable craftsmen who were at the top of their craft and skill. They just had no comprehension of what a 5% relative humidity environment would do to the materials they were using. Living in Ireland, it is possible that you may have a problem with this perspective as well.

I know that when I work on a furniture project that has any complicated joints that the humidity of the wood must be between 8 and 12 percent - or the work does not survive climatic changes. I also know that I have to make special provision when I am joining laminates to solid woods or inlay materials. This also applies when joining dis-similar types of wood (Spruce behaves quite differently than oak) This probably falls more into engineering than craftsmanship, but it is a design reality that I have to deal with. I have a hard time believing that a good luthier would not be as aware of this issue as I am and have craft solutions available to address these issues.

To your last point, I would say that modern instruments (those made in the last 50 years or so) that fail due to changes in the normal range of humidity ( 20 - 70 %) are poorly designed - regardless of how competent the craftsmanship was.

A guitar should be more about how it sounds than about how it is built, but I believe a true craftsman knows how to blend the engineering with the witchcraft. It would be interesting to see if there are specific models and brands that suffer from this design problem more than others (the reason I mentioned my old D-60).

I believe a good analysis in this area would prove my point. I hear Taylor owners complaining about this fairly regularly, but I don't recall hearing these complaints from a Gibson owner (or am I just real biased).
 
mshilarious said:
Put a plywood top on an Ovation back, and you can probably safely ignore humidity. The problem is you have an Ovation with a plywood top to play . . .
:(
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OK, so I'm also the proud owner of a Fender Stratacoustic. Fiberglass body with a plywood top and an easily replacable neck. I don't have any qualms about draging it out-of-doors regardless of the weather or throwing it behind the seat of my pick-em-up truck (self-inflicted redneck humor) without a case. With a good set of strings on it I think it sounds as good as most of the Ovations I have played, but I wanted a steel string that was as usable of a utility guitar as my D-60 without the worries of having to treat it like a stradivarius violin. It is a good piece of engineering - even if it only sounds good when EQd and amplified. No need for humidity control here:)
 
gcolbert said:
muttley600

Throughout the 19th century, well-to-do Americans would buy furniture from the finest craftsmen in Europe and have it shipped to their New World estates. For those who lived East of Chicago this represented a symbol of their wealth and prosperity. Unfortunately, when the wealthy of the West tried to do the same thing they ended up with furniture that split from checking, misfit pannels, non-functional doors and drawers, and tennon joints that failed to hold the furniture together. Mind you, these items were made by the most notable craftsmen who were at the top of their craft and skill. They just had no comprehension of what a 5% relative humidity environment would do to the materials they were using. Living in Ireland, it is possible that you may have a problem with this perspective as well.
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The European craftsman responsible for the furniture you describe we're entirely aware of the properties of timber and how timber behaves in service. The problems you describe occurred and still do for different reasons, mainly that of air conditioning and central heating and peoples lack of awarenesses of the glue lines used in days gone by. They were also aware of the relative humidity of the regions in which they worked and accommodated it. The furniture was never designed to be shipped to wetter/dryer regions. They always built locally and repaired locally, if they were to have shipped their work they would have made the recipient aware of the possible problems as antique restorers do today.

I shared workshop space with one of this countries finest antique furniture restorers some years ago and learned a huge amount as a result. He also learned a good deal from my working practice. I saw first hand the effects of modern and historical mistreatment of furniture and also the exacting standards they used in their work. They were quite remarkable considering the glues and tools they had at their disposal. The timber was as it is today, same properties, same behaviour.

I don't live in Ireland by the way.

I know that when I work on a furniture project that has any complicated joints that the humidity of the wood must be between 8 and 12 percent - or the work does not survive climatic changes. I also know that I have to make special provision when I am joining laminates to solid woods or inlay materials. This also applies when joining dis-similar types of wood (Spruce behaves quite differently than oak) This probably falls more into engineering than craftsmanship, but it is a design reality that I have to deal with. I have a hard time believing that a good luthier would not be as aware of this issue as I am and have craft solutions available to address these issues.
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Moisture in timber is not described as humidity it is described as moisture content.
I can assure you I work to a much tighter moisture content than you do. The problem is not the moisture content of the timber in and of it self, as once you get below 10% on most timbers you are left with what is described as "bound moisture" that moisture takes decades or longer to drop significantly. The "free moisture" or the water that is free to migrate from the cell structure of the wood is pretty much zero at that point and is the moisture that is lost as a result of seasoning. Timber at this point will readily accept and lose moisture and quickly depending on where it is stored and the environmental it is kept in. The only way to stop that is to finish the timber with a protective coating (partially successful) or to maintain the environment that the timber is going to be kept at in service. There is no way you can avoid this and it is this that we are talking about.

To your last point, I would say that modern instruments (those made in the last 50 years or so) that fail due to changes in the normal range of humidity ( 20 - 70 %) are poorly designed - regardless of how competent the craftsmanship was.
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I see far more main brand manufacturers guitars in my shop for repair than bespoke instruments. I have never had a guitar of mine returned for material or workmanship defects as a result of humidity problems. I have built guitars that have been gigged all round the world. If there was a way to obviate the problems of humidity in acoustic guitar design we would all be doing it. Trust me there isn't. You need to keep a careful eye on the humidity changes and react accordingly. Every instrument is different because every piece of timber is different. This is what we are talking about.

A guitar should be more about how it sounds than about how it is built, but I believe a true craftsman knows how to blend the engineering with the witchcraft. It would be interesting to see if there are specific models and brands that suffer from this design problem more than others (the reason I mentioned my old D-60).
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There is no witchcraft involved in guitar building. A luthier who built guitars that didn't stand up to the demands of the modern world would soon be out of business. Those that do make a go of it are completely aware of the properties of the material they work with and how they behave. If you have a suggestion as to how to eliminate these issues I suggest you patent it fast because everyone from the boutique builder doing 10 guitars a year to Martin and Taylor would be after your secret.

There is no make or model that is more or less a problem than others. Martins are over built in many cases and Taylors are a triumph of slick manufacturing processes dressed up as improvements. Both suffer from humidity related problems as do other brands in equal number.

A good guitar maker knows both the structural and acoustic requirements of his instruments and stands or falls on the results.

I believe a good analysis in this area would prove my point. I hear Taylor owners complaining about this fairly regularly, but I don't recall hearing these complaints from a Gibson owner (or am I just real biased).
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I see about a dozen Gibson acoustics a year for de-laminating, neck resets, splits, 14 fret hump etc. They are just as likely to suffer if not looked after properly

I'm pleased you have never had a humidity related problem with your guitars. Others do and that is not a reflection of either guitar design or poor craftsmanship or awareness of the issues. It is entirely down to material properties and the expectations we have of our instruments and the lifestyles we lead. Having said that it is entirely possible to manage the problems with a little care and attention.

About this Yamaha D-60. Where did you get it? I have never seen or heard of one? I'm interested in it's origins and influences as most early Yamaha closely followed existing designs. Any links or info the only D-60's I'm aware of from the big guys are Martin, Guild and Larrivee?
 
muttley600 said:
The European craftsman responsible for the furniture you describe we're entirely aware of the properties of timber and how timber behaves in service. The problems you describe occurred and still do for different reasons, mainly that of air conditioning and central heating and peoples lack of awarenesses of the glue lines used in days gone by.
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First off, let me say that I believe that luthiers are the top craftsmen of all wood workers and I have no reservations in accepting that your craft understanding far excedes mine. Building a nice chest of drawers is not in the same league as building a fine musical instrument.

I don't doubt that a furniture craftsman in the 19th century understood that wood was dimensionally unstable. However, I still believe that the problem with European furniture in the Western States was the lack of comprehension of how dramatic these effects are in a 5% RH environment. Top quality, real wood furniture does not have the same problem today. Something is different now than in the 19th century - and it has to do a lot more with improved understanding than it does with better glue.

Assuming that mshilarious isn't just trying to 'yank our chains,' what would be the cause of his GAT only being usable for part of the year? Just what makes a bridge bulge or a top sink? Somewhere we have support pieces that are expanding or contracting at a significantly different rate than the material the top is made of. Were they cut with the grain in the wrong direction? Did someone use scrap oak and glue it to a spruce top? Possibly the braces should have been finished to slow down their expansion/contraction? The problem with bulging/sinking tops is a materials mismatch - plain and simple. Wrong type of wood, wrong grain, wrong tree - but still a materials mismatch. This is probably exaserbated by all of the new 'exotic' woods and 'replacement' woods (real mahogany?) and not having a good understanding of how they behave.

Could a part of the reason you have not had one of your guitars returned for humidity problems have something to do with your working with properly seasoned wood at a proper humidity level, which could not be as closely controled in a "guitar manufacturing plant?"

There is no witchcraft involved in guitar building.
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Do you mean to tell me that you have never touched a piece of wood and had it tell you what to do with it? Every piece of wood is unique, and sometimes just touching it lets you know what is unique or special about it. Possibly this isn't witchcraft, but it certainly isn't science, and it is something more than just technical craftsmanship.

Because of this uniqueness, It may not be possible to always make a dependable product. However, I still believe that good design, proper material selection, and skillful assembly practices should result in a guitar that does not need to live in a humidor. If I'm right on this there would be statistical differences in the problems shown by model and manufacturer. The sad thing is that the only way to tell if your guitar is a lemon is to see if it has humidity problems.

About this Yamaha D-60. Where did you get it?
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I believe that it may be a pre-production (test market?) version of the G-60/G-60A. I bought it in early 1968, a year before Yamaha started making the G-60s, but it looks just like one. I think I paid all of $100. for it back then. Has the Yamaha label inside with gold-foil stamping of the model and the "Nippon Gakki" manufacturer's mark. No serial number.
 
gcolbert said:
First off, let me say that I believe that luthiers are the top craftsmen of all wood workers and I have no reservations in accepting that your craft understanding far excedes mine. Building a nice chest of drawers is not in the same league as building a fine musical instrument.

I don't doubt that a furniture craftsman in the 19th century understood that wood was dimensionally unstable. However, I still believe that the problem with European furniture in the Western States was the lack of comprehension of how dramatic these effects are in a 5% RH environment. Top quality, real wood furniture does not have the same problem today. Something is different now than in the 19th century - and it has to do a lot more with improved understanding than it does with better glue.
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I'm not going to respond to furniture thing as it is to far off topic for this discussion. On to other points you raise.

Could a part of the reason you have not had one of your guitars returned for humidity problems have something to do with your working with properly seasoned wood at a proper humidity level, which could not be as closely controled in a "guitar manufacturing plant?"
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No. It's down to fact that I explain the issues that may present to the customer and explain the best ways to mitigate them. You understanding of controlled humidity is flawed. It is changes in humidity that is the problem.

Assuming that mshilarious isn't just trying to 'yank our chains,' what would be the cause of his GAT only being usable for part of the year? Just what makes a bridge bulge or a top sink? Somewhere we have support pieces that are expanding or contracting at a significantly different rate than the material the top is made of. Were they cut with the grain in the wrong direction? Did someone use scrap oak and glue it to a spruce top? Possibly the braces should have been finished to slow down their expansion/contraction? The problem with bulging/sinking tops is a materials mismatch - plain and simple. Wrong type of wood, wrong grain, wrong tree - but still a materials mismatch. This is probably exaserbated by all of the new 'exotic' woods and 'replacement' woods (real mahogany?) and not having a good understanding of how they behave.
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Belly bulge and the soundhole dropping down and the resulting change of action on acoustic guitars is pretty much common to all acoustics. Just site across the top of a guitar that has been around for a few years to check this. The reason is simple. The pull of the strings on the bridge wants to yank it off consequently the top around the soundhole dips in and the area behind the bridge wants to rise. The solution to this has always been the type of bracing and how it is laid out. It is possible to increase the amount bracing and the position. It is also possible to increase the thickness of the top. The downside is that you then begin to dramatically impact on the response and tone of the guitar. Rapid and constant humidity changes will accelerate this issue. Don't forget we want the top to move. It is that that makes the thing work. Take away the ability of the top to move and you get little in the way of sound or tone.

The spruce that is used for the top is always cut on the quarter to minimise the potential for indiscriminate movement. On my guitars and many other higher end instruments the spruce is not only cut on the quarter but also cleaved to get the grain as close to true as is possible. I'm afraid from what you are saying about the choice of timbers and how they are used in guitar construction and the effect this has on overall performance demonstrates that you really don't have a clear understanding of the demands of instrument building. Much of what you say is simply is not the case.

Do you mean to tell me that you have never touched a piece of wood and had it tell you what to do with it? Every piece of wood is unique, and sometimes just touching it lets you know what is unique or special about it. Possibly this isn't witchcraft, but it certainly isn't science, and it is something more than just technical craftsmanship.
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I hand select all my timber based on a very strict set of criteria. When I do so I know exactly what the piece of timber will be used for and what demands will be placed on it. I have a good idea of how it will behave in service and what can not be expected of it. From years of experience I can hopefully get the best balance of tone and structural stability from those timbers. That is down entirely to craftsmanship and experience when working with it backed up with a vast amount of material science knowledge. That knowledge and experience is also held by all established guitar builders and also by the big guys who mass produce. Once again if there were simple solutions to the design issues and selection and application of materials that avoided problems related to timber properties we would know of them and use them.

Because of this uniqueness, It may not be possible to always make a dependable product. However, I still believe that good design, proper material selection, and skillful assembly practices should result in a guitar that does not need to live in a humidor. If I'm right on this there would be statistical differences in the problems shown by model and manufacturer. The sad thing is that the only way to tell if your guitar is a lemon is to see if it has humidity problems.
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What you fail to grasp is that is impossible to fashion an guitar that will be happy in all possible environments. If you ask me to make you a guitar that will not be effected by humidity changes I would have to ask you to maintain the humidity to within one or two percent of a constant value. It doesn't matter what that value is just that YOU keep it constant. But wait that is pretty much what we are saying here. If you allow the humidity to change the timber WILL respond. Fact. Unavoidable. Timber is an anistropic and piece unique natural material you cannot get round it.

I believe that it may be a pre-production (test market?) version of the G-60/G-60A. I bought it in early 1968, a year before Yamaha started making the G-60s, but it looks just like one. I think I paid all of $100. for it back then. Has the Yamaha label inside with gold-foil stamping of the model and the "Nippon Gakki" manufacturer's mark. No serial number.
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Never seen one. I'd be interested in some pics and details. Does it have a solid spruce top or is it laminated like many of the pre production Yamaha's of the day?
 
muttley600 said:
What you fail to grasp is that is impossible to fashion an guitar that will be happy in all possible environments. If you ask me to make you a guitar that will not be effected by humidity changes I would have to ask you to maintain the humidity to within one or two percent of a constant value.
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This was the reason for mentioning the old Yamaha. It is, in fact and demonstratably, possible to fashion a guitar that will be happy in all environments. The only question here should be if the acoustic (sound quality) trade-offs worth having a worry-free guitar.

And then back to the OP - Is the concept of humidifying a guitar case being "SUPER IMPORTANT" snake oil or is it science. It seems that we agree that the problem is the changing of humidity that is the real problem. If we both accept this as the real problem then humidifying a guitar that lives in a very dry or high altitude environment would be a bad idea.


The back and sides on the Yamaha are a very thin laminate - two possibly three ply. I'm unsure of the top, but I would imagine that it is the same.
 
gcolbert said:
This was the reason for mentioning the old Yamaha. It is, in fact and demonstratably, possible to fashion a guitar that will be happy in all environments. The only question here should be if the acoustic (sound quality) trade-offs worth having a worry-free guitar.

And then back to the OP - Is the concept of humidifying a guitar case being "SUPER IMPORTANT" snake oil or is it science. It seems that we agree that the problem is the changing of humidity that is the real problem. If we both accept this as the real problem then humidifying a guitar that lives in a very dry or high altitude environment would be a bad idea.


The back and sides on the Yamaha are a very thin laminate - two possibly three ply. I'm unsure of the top, but I would imagine that it is the same.
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I rest my case.

I'm sorry, but a ply laminate guitar does not behave as a top end all wood constructed instrument. There really is nothing further to say but I would politely suggest that you bone up on exactly what constitutes a well made and designed acoustic guitar and why certain timbers and construction methods are chosen over others. I would be happy to expand on any of it if you have any questions.

The need to control the humidity of the storage area or case of a guitar is driven in all cases by the fact that us repair guys and luthiers see loads of instruments coming through our hands for work after movement in service. especially at times when the humidity levels are changing dramatically such as the change in seasons in most temperate climates.
 
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muttley600 said:
I would politely suggest that you bone up on exactly what constitutes a well made and designed acoustic guitar and why certain timbers and construction methods are chosen over others. I would be happy to expand on any of it if you have any questions.
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I hope that I will always question the status quo, but I also hope that there will be experts (like Muttley600) who are patient enough and willing to explain why we got to where we are. Thank you for your time and patience. I don't completely buy into your position, but I do have a broader perspective.
 
If all gats were as sauced as I am (arthritis self-medication), guitar repair-type people would be out of business!

I love you J. Lo!!!!! :o
 
gcolbert said:
I hope that I will always question the status quo, but I also hope that there will be experts (like Muttley600) who are patient enough and willing to explain why we got to where we are. Thank you for your time and patience. I don't completely buy into your position, but I do have a broader perspective.
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It's not really a matter of buying into my position it's more a case of being aware of what an acoustic guitar is and the compromises that are involved in the design and manufacture. Like many things in life we have to work with what we have and the materials dictate that certain compromises are inevitable.

A classic example of this is the case of the guitar you mention. Ply laminates are used for several reason and one of them is that the product is dimensionally more stable than solid timber. The downside is that it is acoustically less desirable and generally speaking builds a less responsive instrument. There are scientific reasons for this and they are well documented.
 
Alleykat's are cool! I really like mine. If you hang your guitars it's a good idea to use a room humidifier.
bloozkat2.jpg
 
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