http://www.caswellharps.com/index.htmlHot News!enuser@domain.comCopyright 2011 Chris Caswell2011-09-01T14:47:37-07:00 hourly 1 2000-01-01T12:00+00:00 Mon, 15 Aug 2011 15:43:51 -0700user@domain.comWoodHistorical2011-09-01T14:47:37-07:00http://www.caswellharps.com/page63/files/5440ed1fd54f57513b7c0622e62adb82-2.html#unique-entry-id-2http://www.caswellharps.com/page63/files/5440ed1fd54f57513b7c0622e62adb82-2.html#unique-entry-id-2When I was studying harp with Jean Campbell and Alison Kinnaird in Edinburgh in 1971 I remember seeing a paper done by an academic from Sterling who did an analysis of the wood in the old harps–I'm guessing the two Scottish ones, the Lamont and Queen Mary. My memory fails, but I think he said they were either Plane or Deal.

Deal being a somewhat generic term, modernly meaning a board of certain dimensions, not a particular tree, could be in this case is Scots Pine. Scots Pine is very similar in properties to Sitka Spruce and Douglas Fir. All are stiff and tough. Doug Fir is the preferred wood for framing houses, and they used to make masts and propellers out of Sitka Spruce.

Though a softwood, It's a mistake to think it isn't strong. For example, Yew is a softwood, but very hard! It's what they make longbows out of (I experimented with using it as a centerstrip on harps, but it's very hard to come by). And Basswood, a hardwood, is quite soft.

European Planewod (Platanus acerifolia) when cut on the quarter is known as Lacewood. It's a hardwood: strong, but difficult to dry without splitting and signficant shrinkage.

The old sources mention a varietyy of local woods, including willow (European White Willow) and "bog oak" which may have been wood recovered from underground (similarly, Boxwood, treasured for flutes, is buried for about a generation before working it).

I've made a harp out of willow, and several out of similar woods such as Laurel. White Willow is tough and light and doesn't split easily, which would lend itself to an instrument that wants to split. But in general, woods grown near water tend to be softer, and those grown in dryer areas (like the east-facing side of a mountain) are harder - even among the same species (often, when ordering Spruce, one can ask which side of the mountain it grew on). Don't confuse this with wet climate woods. Some of our hardest woods are from the rain forests.

You can look at a tree in its environment and get a notion as to how it might be as lumber. A tall Amazonian needs to support the canopy at its top, so it's probably going to be a good beam. An oak grows out, down and up, so it must have great strength against bending. And indeed, those long low elbows became the keels of many a ship. A willow bends and dips. It becomes an excellent basket.

So one way to choose a wood begins with looking at its strength in the ways you need it to be strong: Is it prone to splitting? Is it stiff? Does it glue well? Does it dent easily?

Next comes a sense of its tone. When you tap on it with your knuckles (holding it so as not to dampen the tone) does it ring? When you rub your fingertips lightly up and down it, does it sound bright like a cymbal?

An example: I recently noticed a harp maker extolling the virtues of Poplar, another moderately strong hardwood commonly used in the industry as an inexpensive "filler" under fancier facings on hardwood laminates. It's used for casework in shelves, etc.,"behind the scenes." There's a lot of it around any shop that builds kitchen cabinets, and since I'm in a co-op with a bunch of "box-bangers" I've had a chance to bang on Poplar a lot. It's great virtue is that it is forgiving to work, and glues and holds a screw well. But it's never impressed me in the tone department. Nor does it have what we call visual "character,"

Which brings me to the final criterion. The wood should have visual interest and depth, especially when you rub the finish on. Woods like Koa (Hawaiian Acacia), and Cherry, and Walnut, and Maple take on an amazing 3D effect when you hit them with that shellac!

We have a great number of instrument makers working with many species. This provides us with a lot of information on how they sound, how they hold up, etc. This experimentation is nothing new. My wife, Roxanne, is currently on vacation in Florence, Italy, and just yesterday saw a violin by Stradivari with a Spruce soundboard and a Walnut body.

A great example of a wood that has gained importance is Koa. This gorgeous wood has become extremely popular with guitar makers, and is ackowledged as a great tonewood. But it is slow to recover from logging, taking about twenty five years to mature so the supply has dwindled. (A local substitute is Black Locust, planted in suburbs in the '50s and being pulled up as they rebuild these neighborhoods. Luckily there is a thriving industry in salvaging these woods. I use this wood almost interchangably with Koa as soundboards for my wire strung harps.)
]]>user@domain.comStrings2011-08-15T15:47:53-07:00http://www.caswellharps.com/page63/files/a08e934246325695540e0a19e4903491-1.html#unique-entry-id-1http://www.caswellharps.com/page63/files/a08e934246325695540e0a19e4903491-1.html#unique-entry-id-1This is from a discussion in the Virtual Harp Circle group concerning what to do if you don't have the needed information to know what replacement string to put on a harp:
 
Harp players worry about keeping with the original string chart for their harp. But in my case, I'm continually messing with those charts, trying this and that, to dial in the sound and feel of my harps. This is an indication that the harp is neither as precise nor as fragile as some would have you believe.
 
If you're in doubt about what to put on, and you have a mess-o-strings from which to choose, take a squint at the broken string (or its neighbors if it's missing) and pick something close. Put it on and pull it up to pitch. If it's too stiff and a bit dull, then go one notch lighter (smaller diameter). If it's too jangly or slack, then go a notch thicker. (Tone, however, is not as reliable a determnanat ina new string as feel. It takes a few days for a string to conform the the points its bending over. Until it does, it'll sound dull compared to its long-strung neighbors.)
 
To allay one's fears about doing this; that is, to see if it's significant or not, let's mess around with one string as an example. (Important note: We're only talking about monofilaments here, not wound strings.)
 
Let's pick a string in the middle of the harp. The E above middle C on my SweetHarp29 is 21.4" long. In nylon that's 45% of tensile strength and it's normally got a .045" string on it. And the whole harp has 1102 pounds pressure on it. Okay so far?
 
If I put a .040" nylon on it, the string goes from being at 31.8 pounds tension to 25.1, a decrease of 6.7 pounds. Remember - it's still at 45% of its tensile strength.
 
If I put a .050" nylon string on, it goes up to 39.2 pounds, an increase of 7.4 pounds, and is still at 45% tensile strength.
 
But what does that mean, adding or subtracting 7 pounds tension? You need to look at the whole harp. The whole harp normally has 1102 pounds tension on it. When I put the .050" string on, it now has 1110 (rounding up). The difference is well less than 1% of the total tension. If your harp is built so close to the edge that a change of tension of under 1% is a problem, I would immediately put the harp down and quickly back away from it.
 
What if you go to carbon? Well, the main difference is that it's now at 70% of tensile strength. And since it's normal to go one size down for carbon from nylon, instead of a .045" I put on a .039". The tension goes from 31.8 to 39.5 pounds. Essentially the same as going from the .045" to .050" nylon (except it's nearer the breaking point).
 
Have you ever had to tune a string up half a step? Maybe you don't have levers, or you want to record without lever tone? On our E string, if I tune it up to F (just an example), I go to 50% tensile strength (from 45%) and up to 35.7 pounds, an increase of 4 pounds–or less than 1/2 of 1% overall tension. So that's not a problem either.
 
Remember, I'm talking about a string here or there. I emphatically do not recommend increasing either the pitch or diameters over the whole harp! And in changing diameters, I am only suggesting going up or down one size. In fact, this is how we fine-tune the sound and feel of our harps. The changes we're talking about are normally quite subtle. Do I go up a diameter at the E or D? Do I switch to Carbon on the C or B? These little changes are often enough to smooth out a transition from one material to another; or to give a "light" instead of a "medium" feel; or to fix a string that didn't have the same resonance as its neighbors.
 
We harpers, in general, are way too cautious about messing with our strings. And frankly, the abjuration from some harp makers or others to only use this or that brand, etc., or not to change diameters is a bit like the Wizard of Oz behind his curtain. It's time harpers got empowered concerning their strings. Time for Toto to pull aside the curtain!
 
If nothing else, remember this: 1. changing the diameter of the same material does NOT change how close it is to its breaking point; 2. Increasing or decreasing the diameter one size on one string of the same material is an insignificant change in tension to the entire harp.
]]>user@domain.comStrings2011-08-15T15:43:58-07:00http://www.caswellharps.com/page63/files/338c65c17a52cfb7654b72afe9acdcfc-0.html#unique-entry-id-0http://www.caswellharps.com/page63/files/338c65c17a52cfb7654b72afe9acdcfc-0.html#unique-entry-id-0(I wrote this as part of a discussion on the Virtual Harp Circle on Yahoo)

It might be good to clear up the way we talk about strings. To my way of thinking, "light" or "stiff" stringing is the result of two very different factors, and we as a community would benefit if we spoke with at least some generally agreed-upon terms.

LONG VS SHORT STRINGS: If I'm using nylon (just as an example) for a string at a certain note, I can figure its vibrating length at any percentage of that string's breaking point I want. So I put it at around 60%. When I pluck it firmly, I'm approaching 80%. If I go much higher than that, I risk breakage. Also, all materials vary slightly so I want to be safely within that fudge factor (I know of one harp maker who claims his strings are accurate to within ±.002, which is the tolerance given by the material's manufacturer and has nothing to do with the string making) . If I go below about 35% of the breaking point the string starts to act like a slack rubber band.

All else being equal, a longer string is stiffer, and a shorter string is slacker. Longer string lengths exert more energy on the soundboard creating a more responsive harp; shorter strings less (talking about monofilaments here). But much longer lengths may break more, shorter less. It's a balancing act. And it's why you've probably never broken a string on a Harpsicle–they're short string lengths.

Oh, also, all harps start in their upper range at the maker's chosen target % and slowly fall away from that as it heads towards the bass. So my harps might go from, say 62% in the treble to 35% in the bass. And this is for a particular material - nylon, carbon, bronze, etc. This is because that theoretical 60% length in the bass wouldn't fit in your living room, it's so long.

Also, it's important to know this when changing string materials, say from nylon to carbon. A string at 62% nylon becomes 94% of breaking point with carbon on it. You're definitely going to be breaking strings (but this explains why so many harps with short flubby strings get a new lease on life with carbon strings).

THICK VS THIN STRINGS: This is what guitarists are talking about if they put on "heavy", "medium", or "light" strings. What most folks don't get is that if I've got my nice 60%-of-breaking-point-string, I can put a FAT length of nylon (or whatever) on it or a THIN length of nylon on and it's STILL at 60% of its breaking point! A thicker string will feel "stiffer" and a thin on "slacker" but for different reasons (and in a subtly different way) than in the Long/Short String case. A thicker string also increases the tension (For example, a 60% nylon G, 10 1/2" long, with a .028" diameter string exerts about 16 lbs pressure on the harp. Go to .045" and it jumps to 43 lbs!).

We can use the diameter of the string to fine tune the tone and feel of an instrument to some degree. For example, if your Harpsicle feels slack, a slightly thicker string will stiffen it somewhat. (I''m not necessarily recommending this since one needs to know that a harp's construction can handle the slightly increased tension, but really, a few strings different here and there won't affect any harp that much. A whole set of heavier ones, yes!). Or if your big harp has a dull upper midrange, you can decrease the diameter of a few strings in that area and brighten the sound up a bit - but at the expense of a slightly slacker feel.

So just saying "medium light" or "stiff" stringing doesn't really tell us much. How about we come up with something like "60 to 30 carbon" or "55 to 25 nylon" etc, to indicate the string lengths' range of % of breaking point and which material it's designed for. Then we can say if we're putting light or heavy strings on it.

In fact I'm inspired by this post to do this with my harps. I'll start with the SweetHarp: it's a 62-35 nylon/carbon (it goes from 62% breaking point to 35%, designed for nylon in the top and carbon in the bass).

A good system for quantifying "heavy", "medium", or "light" strings I'll need to think about. Any ideas?


PS: FWIW I think Tynex is still a great stringing material, even though carbon is the string du jour (and definitely has a place in our panoply of stringing materials). Tynex is a "type 60" nylon - the original one. It's stiff, tough, and it's breaking point is very near its yield point meaning it will stretch slightly but not much, and not continually except under certain conditions. Other nylons (and carbons) can be self-damping (a BAD thing for musical instrument strings) and stretch sooner and forever.

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