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These are all great questions Elletaria. Probably the best way to address them is to think about a harp’s design conceptually, so let’s start with an electric harp as the simplest concept .
Point 1: There is no sound box and no sound board to speak of; all you hear is the string’s vibrating against a piezo pickup. Those plug into an amplifier (with of course usually a modulator). With the Waring or any other harp the box is just the “amplifier” and the flexible sound board acts like a pickup. Conclusion: you can build the frame (neck, column, and board) separately and just tack on the amplifier part (the box).  That’s the principle behind the Waring and indeed the Harpsicles.
Point 2: Strings can be anything that is strong enough to carry required tension without breaking but not so elastic as to sound like a rubber band. Conclusion: your string band design is very important, so start there; beg borrow or steal a good design with fairly light tension. For a harp this size I’d suggest 23 or fewer strings, starting at G below middle C. Write me off list for one such design, or look at the Harpsicle and Musicmakers’ Limerick for inspiration. Or turn to a string designer as you mentioned. Personally I don’t think it is worth spending the money on Nylgut vs. Tynex for this small size, but that is up to you.
Point 3: There is no such animal as “standard spacing” among small harps. Those who play with their finger pads prefer wider spacing than those who play with their nails. As a generality that might be respectively about 1.25cm and 0.9-1.1 cm. Now think abut the angle where the strings meet the board at the player’s end. That may be from about 25 to 40 degrees: a smaller angle means a taller harp and less volume than a larger angle. To compute the spacing at the board dig up your trigonometry. The spacing at the board will be Xtan(Z) where X is the chosen spacing and Z is 90 minus the string angle (in degrees, or use radians if you must). Then draft the harp’s profile with the chosen vibrating lengths.
Point 4: Volume depends on many things, largely on the thickness and width of the board (vibrating surface). Air must move in and out and you need some way to access the strings. Study the wire strungs like you Ardival: sound holes are in front and you access strings from the front. There is however no formula to dictate the holes’ sizes other than “less is more.” For a little 19 – 23 I’d put access holes in the back – in fact I might just use one long narrow one, say 5 cm wide.
Point 5 and last: The SB length will depend entirely upon your string spacing, and width at top and bottom somewhat arbitrary. A good size for a 19 might be 25.5 cm wide at the base and 11cm at the top. That is essentially the Kilcoy – if you choose wider string spacing than the Kilcoy the board may of course be longer (by perhaps 6-7 cm) depending on your chosen spacing and chosen string angle. Some wire harps (in fact most in the US) use wider spacing than a traditional clarsaech since makers assume their market is mostly gut/nylon harpers. There is no reason you should not go the other way: use let us say 1cm spacing and play nylon with nails.
Can’t help out with zither pegs and bridge pins in the UK, I’m afraid, but postage and customs would not cost too much if you order from Dusty Strings or Musicmakers for instance. Just be sure that the peg’s string holes are oversize if the string diameter is larger than 0.040″. Both often show up on eBay too. I have a bunch too (used) which you can have if you tell me how many and if you need a few oversize.
Have fun!
Biagio
Hi Elletaria,
The reason harps have that curve is because the frequencies of the occidental diatonic scale is an exponential one, there is not getting around that fact. Think about it this way: going from low A to high A for instance it goes from 55 Hz to 110 to 220 to 440 to 880 to 1760. What that implies in terms of string acoustics and physics is that for a given diameter the length would double in length going in the opposite direction. That makes a pretty tall harp! We get around that by making lower range strings heavier and therefor shorter, but except on a very small and lightly tensioned harp the the neck will not be straight and look pretty. You are stuck with a harmonic curve. You could use a straight board of say 8″ wide but the pegs are still going to curve up from treble to bass. Or if the pegs are in a straight line, the lower you go the lighter the tension of them will be – which is exactly the opposite of what we want in a harp that sounds good.
That leads to fretting against the neck. The strings must be close enough to the neck to be able to do it and it is not easy even if they are. James is a friend and I respect him, but when he suggests no bridge pins he is talking from a wire harp perspective. It is rather pointless to leave them off a nylon strung harp unless you intend to play it like a wire strung.
With that out of the way LOL let’s address spacing. A half inch (1.27 cm) is a very typical spacing in the mid to treble which is the range you are looking at in this endeavor. The issue is: how do you lay it out given your string lengths? You can buy a work sheet from Musicmakers or make your own. Here’s how:
Get a large sheet of drafting paper, say 1 meter by .60 meters, preferably graph paper laid out in 1/4″ or millimeters. If you cannot find graph paper – draw 19 or more parallel lines on the long direction. The draw a sloping line at the angle you have selected. That represents the sound board; measure up from that for each of your string lengths. Voila! You have now located where to place the bridge pins (or tuning pegs if you cant to leave bridge pins off).
Let’s assume bridge pins for the sake of completeness though. Harp strings seem to be happiest when they slope from 15-25 degrees back from the pin to the peg at a distance of 1″-1.5″ (2.5-3.8cm). Draw those lines and now you know where to put the pegs.
To answer our question about the range: the lower you go the longer the string or the heavier. That F you mention would have to be fairly long or else wound to sound any good. The G above it would be 0.060 diameter Tynex which is as big as it gets. You could go to Nylgut or Savarez Allliance for that F however but to repeat:
Do the string design first.
I tried to post the design for a little 23 but it looks all goofy, so email me offlist an I’ll send it to you, along with instructions for using the analysis program it is in. You really do need to understand string theory to make a harp; read Rick Kemper’s String Theory discussion and go from there:http://www.sligoharps.com/string.html
These harps were about 28″ high and 15″ wide at a 35 degree string angle but remember what I said about the angle? If you changed that to 40 degrees it would be shorter and wider. I suggest that you get the grid or drafting paper and play around with this to get a “feel” for the process when I’ve sent you the analysis.
The Rosemarkie is a very light tension medieval harp and if that’s what you want, go for it. Although the neck is straight you will notice that the strings themselves still follow a geometric curve, and in fact splay in the treble. I think you would be setting yourselves up to a lot of work trying something like that. And you will still need to do a analysis if you want decent tone. I’d really suggest doing something simpler first go.
Cheers,
Biagio
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