Double basses and winter humidity issues

We are experiencing an unusually long and cold winter this year, and in my workshop there is a queue of cracks and buzzes to be attented to. Humidity levels in winter and how they relate to instrument care is something I spend a lot of time discussing with customers. My own opinion is not necessarily gospel truth and I'm still collecting data - when it comes to basses it's an inexact science - but this is what I have to say.

Relative humidity: Cold air cannot hold nearly as much moisture in it as warm air. What happens in winter is that cold air from outside, which contains low but relatively speaking quite acceptable moisture levels, comes into our living spaces and is warmed up by our heating systems. While the actual amount of moisture in the air remains constant the warm air is now relatively speaking very dry and this can cause problems with musical instruments.

What dry air does to your instrument:

Wood: When wood dries out it shrinks, mostly between the grain lines. This means that when you look at the table of your instrument, with the grain lines running down the length of the instrument, the width will decrease slightly over time. If it shrinks too fast a crack could pop open running along the length of a grain line. What compounds the problem is that the instrument is constructed in such a way that the grain lines in the ribs, table and back run in different directions, so that when shrinkage occurs it creates tension in the instrument. What can then happen is that the ribs, which shrink along their width much more than their length, become too long for the shape of the table and pop out of line. Added to this is the fact that a many basses are made from wood that is at least partially slab cut (you can see this in the pretty circular grain patterns in the upper and lower bouts). This can create a tension which pushes the two edges of a crack out of alignment, making a straight forward gluing job impossible. Wood that has been well seasoned will present with fewer problems.

Glue: Dry air also affects the hide glue used in instrument making. This is less serious. The glue shrinks as it dries, bringing the two sides of a joint tightly together. Moist glue is quite elastic, but it become more brittle as it dries. This means that in dry conditions seams of glue can become so brittle that they open up, usually between the ribs and table or ribs and back. This is easily rectified.

String height: On some instruments the string height changes with the season, so that the strings end up lying too far or too close to the fingerboard, affecting playability. An adjustable bridge or summer/winter bridges is usually the answer to this. Some instruments need a higher bridge in the winter, some need a lower bridge, and many are quite stable and don't need adjustment at all. I have not yet found rhyme or reason why this is so. There are just too many varying factors involved. Wood is a very complex material and behaves in a unique manner in each instrument. On instruments that do change a lot seasonally it is a good idea to keep an eye on the tightness of the sound post. Some instruments need different length sound posts for different seasons both sound wise and as insurance against possible sound post cracks.

Humidity control for bass owners

We have several hygrometers (humidity gauges) in the workshop and they all show different measurements. There are ways to callibrate them, but it's important to realise that they can be unreliable. Luckily we humans, like our basses are also sensitive to humidity levels. If you feel the dryness in your nose and your lips, you know that you need to need to do something about the humidity for your own sake as well as your bass's.

Room humidifiers: This was one of the first thíngs I invested in, but it made so little difference to the humidty in the workshop that I just returned it. There are simpler methods which I use e.g keeping water containers by every radiator. When the temperature drops below minus ten outside I start boiling water in the kettle with the lid off 10 mintues at a time and I'll have a steaming pot of water on the stove all day (which I use anyway for glue). The cheaper humidifiers available may be sufficient for a small room, and I'm sure that there are sophisticated expensive ones available too which would be effective. I'd be interested to hear of other people's experiences.

"Dampits": I'm not a "dampit" fan. The danger with them is that they drip water inside the bass which leaves stains in the wood and mixes with the dust inside to form a kind of cement which is a nuisance to clean. The drops of water can also dissolve glue and seams can open. As general rule when it comes to drying or moistening wood, the slower the better. The structure of the wood can be damaged both when the cells collapse suddenly due to harsh drying and when the cells expand suddenly when water is dropped on them. So if you use "dampits" make sure that you wipe off the drips. Otherwise just keep your bass inside its cloth cover when you're not playing.

What to do about cracks and buzzes:

Open seams and some cracks are easily fixed with a bit of warm hide glue and a clamp. For others it may be necessary to open the bass so that they can be properly glued and reinforced. Sometimes I'll choose to leave a crack open until a later time when the instrument can be opened. Some cracks can be glued provisionally and then reinforced from the inside at a later date. Some cracks will create a buzz, some won't affect the sound at all. Some are really obviously, others are quite secretive. Buzzes are a whole mystery in themselves and can have many different causes. If you find a crack or open seam on your instrument that does not affect its playability, it can be left until a convenient time to fix, say within a few months or so, depending. But if it is left too long there is a danger that it can get worse if it has been caused by tension and it can also collect dirt and be more difficult to fix invisibly. 

So my advice to players is check your instrument reguarly and bring it in if you have questions, to me or another repair person whom you trust. What I have written here is as much as I can say without actually looking at your instrument together with you.

On Kora Making and Violin Making

So I finished stringing up my kora over the Christmas break. It was maybe the hardest part and involved some several spectacular explosions and entanglements as tailwires snapped and the bridge collapsed, but after experimenting with stronger materials and about a week of constant retuning it's now playable and the tone is developing nicely. I thought I'd try and do a little recording but neither the mike I have nor my playing does anything approaching justice to the sound.

But I'm very pleased. Two months ago my awareness of the kora as an instrument was of a vague west african bewilderment of strings. Then on 2 november I discovered the music and was hooked. I listened and listened and researched and found that there was a place in England which sold kora kits and I thought rather sensibly that that would be the way to start, with something semi-fabricated in west Africa. So I wrote off to them, right away regretting it slightly, because I really wanted to make one that was really my own, from scratch, truth be told. As it turned out they were busy with Senegal-trips so I was free to do my thing, in fact I felt that I now had the liscence. On 2 december I visited a little shop in Gothenburg and bought the calabash and hide. And now on 2 january the instrument is finished and tuned, quite amazingly as it was along side other work I was busy with. My first violin took me a whole year to make. So what's the deal with violin making vs kora making? Is the kora just simple and "primitive" in comparison with the more sophisticated violin? Ooo that grates me. I may have developed an allergy toward the negative associations of the word primitive.

The kora originated according to oral history about 700 years ago amongst the Mandé people in the Empire of Mali. It's older than the violin. It is built of 4 elements: the gourd representing earth; wood representing plants; skin representing animals and iron representing magic. Some instruments are inscribed with magical qu'ranic symbols on the inside. How exciting is that! Traditionally played by members of Jali (griot) families it's common that the musicians make their instruments themselves. In some families the kids start by making their own kora, then they learn how to play and only when they are quite proficient is an instrument made for them by reputed maker. In the violin world, making and playing have been two quite separate things, which is rather sad in a way.

So if I'm to learn to play the kora, making my own instrument first is really the ideal beginning. I wasn't born into the right family, but all the necessary knowledge was there in my education and experience and on the internet. Cool.

What impresses me about the kora is the simplicity yet perfection of the design, the perfect suitablity of the materials (gourd and hide), the natural ease of contruction. There is another kind of perfection in a violin, the culmination of rennaissance sophistication that become a classic form, which despite the advances of technology remains largely unchanged today. One could argue that the violin is a representation of man's triumph over the forces of nature. Think of the extravagent environments in which it was first played.The form is a sophisticated geometric construction, not found in nature but in the mind of man. The materials submit to the will of the maker and are formed through his tools into the preordained result. Unfortunately it this becomes a kind of tyranny when you consider the way violins are mass produced today. The trees are mowed down and the barely seasoned wood is machined to the exact same measurements used by Stradivari, unaware that in the process something vital is lost. Nature is violated, the instruments just don't sound the way they should and it all ends up becoming some sorry sacrifice to the gods of consumerism.

The kora comes from what today is one of the poorest places in the world, once the centre of the slave trade, though it too was played in the courts of kings. But the kora's form comes not from the cerebral heights of man's conquest over nature, but from thousands of years of interplay between man and nature: from the cultivation of the calabashes; the domestication of livestock; the rending of iron from stone. A dialogue  between man and nature rather than a dominion. It is nature that determines the form of the sound body, not Euclidian geometry. (The geometry behind the violin form is by the way really interesting, although it is a part that is often skipped) The round gourd is simple yet amazingly strong and thicker at the points it needs to be. We would have trouble building anything like it out of wood, a fibreglass mould maybe, but then the dialogue would be silenced. Hide also has inimitable qualities. The natural materials tell a unique story of the life they once contained, a life nutured in the balanced interplay between mankind and nature.

I do not mean to say that either kora making or violinmaking is superior. As with violinmaking, there is also a risk that tourism creates an unhealthy demand for cheap replicas of koras, which will provide money in the pockets of some people but an imbalance in nature. My point is that instrument making is based on traditions, whether they be of cerebrally dominated rational learning from the courts of enlightened europe or of the undocumented mystical interplay of man and his surroundings from the courts darkest africa, but it is also a dynamic and living craft. If one dismisses kora making as something primitive, one loses an important lesson: that good instrument making involves communication, a balance, a dance between the maker, his tools, the materials and nature itself. Of course this is something that the great violin makers of the past and today do instintively.That kora making is "simpler" than violin making to my mind is just a bonus as it allows more accessiblity. I believe that music should not be elitist and the making of an instrument needs not be a mystery to the player.

Creative Problem Solving with Plaster Casts

The big project of the moment is correcting the arching of a bass table. It had had a bass bar that was fitted with with far too much tension causing the whole table to warp. The sound post side was also pushed up out of proportion. So I built a bass shaped container and made a plaster form of the table. After correcting the plaster form I needed to find a way of applying even pressure over the entire table. This is usually done with bags of sand, but hey, since mid november all the sand has been frozen under half a metre of snow. What to do? Hmmm....Pling!! Sugar is like sand.

When I started the business I got lots of advice about how I should put exactly everything that I buy through the business to save on tax. Well, I haven't actually done that in practice. Apart from not feeling entirely honest, it makes for a lot of boring bookkeeping, so things that I buy for the workshop go through the business, and the rest I pay for myself. I maybe the poorer for it but I do sleep well. Relevance? My brainwave was that I could buy loads of sugar to press in to my bass form and then afterwards take it home to make pretty christmas candy. 1. bass form (tick) 2. cosy family activity (tick) 3. edible christmas presents (tick)

This was just a test run, but I liked the look of the plastic bags filled with suspicious white powder. The actual procedure involved warming everything up with hot air, dampening the wood with hot water, layers of paper to absorb the moisture and then bags of sugar carefully arranged for even pressure (sugar has the added advantage of holding the heat well) and finally quantities of wood on the top for extra weight. Repeated several times.

After all that, I boiled up the sugar with food colouring.

Meeting Koussevitsky's old Double Bass

The other day I got to visit the orchestra at Konserthuset with my little bag of tricks. A new bass had just arrived and the bridge and sound post needed to be put back into place. Luckily that was simply done and I was able to spend a good long time admiring it together with its proud new owner.

This is no ordinary bass. It was once the property of the virtuoso Sergei Koussevitsky. Not to be confused with Gary Karr's alleged "Amati" which he got from Koussevitsky's widow, this "Tononi" is a much smaller instrument (string length 97cm, though you would never guess from looking at it). According to the seller there is no proof that it was in fact made by Tononi but it does in all likelihood come from Bologna around 1720. It certainly is a magnificent instrument and it has the most wonderful form and full arching which is not evident in this picture. Accompanying the instrument is some interesting documentation and I hope that its present owner will be able to piece together and bring to light a considerably more exciting story than what is presently available at http://en.wikipedia.org/wiki/Sergei_Koussevitzky

It was certainly a great privilege for me to be present when the first notes were played and I'm looking forward to making a new bridge for it in the new year.

Kora Diary 3

Provisional fitting of the neck. Koras can be up to 1.5m tall. This one is 1.4m at the moment. I might take a bit off after I've plotted the string lengths, not sure yet.

The sound hole turned out rather nicely I think. The calabash is very obliging to cut shapes out of. I'm sure I can use the African shaped piece that came out for something too.

Kora Diary 2

Had a brainwave of threading guidelines through the skin for the crossbars. It worked nicely.

The crossbars I made from an old double bass fingerboard. I didn't turn them, I formed them with a spoke shave, and drilled holes so I could thread them through the holes.

Wow, it really looks like a kora!

It's a bit asymmetrical, so that there is space for the sound hole on the left side there.

Kora Diary

It was so pretty this morning when the sun came up that I took my goat skin outside for a quick photo shoot. 

But it was so cold -14 or something that I had to hurry back inside. I'm using the cellar of this lovely building for my kora project, at least the skinning part. It used to be the kitchen where they made all the food for the course participants a hundred years ago. Here is the old stove:

The goat skin is from Senegal, shaved african style with a razor blade.