Camac Bardic 27 help!!!

[Biagio]

Tracye, my point exactly!

I’m sometimes asked, “Could one convert a Music Maker’s Limerick to brass or bronze?” The answer is, “Yep it’s nice that way if you drop the range 3 steps.” It’s a low head which makes conversion easier.

On the subject of tension: sometimes makers and players mean different things by that term. As a designer I use “tension” to mean the actual force directed against the sound board and frame. Many players use the term to mean how stiff the strings feel, which is entirely different.

As a “for instance” my 26 string bronze wire harp is at 530 lbs; my 26 nylon at 750. But the wire strung sure feels “tenser”! It also incidentally sounds pretty good with gut, despite the solid maple soundboard.

But I dither on…..

Biagio

[Biagio]

Mae, I apologize for coming in late and missing some important info (and getting pretty long-winded). Maybe this will be more helpful…

Gary’s Brittany is very similar to a bunch of 2×23 double strungs that I made for a retreat (mine go up to A instead of G but no big deal). I sold a couple overseas and the folks wanted to know what they could use instead of nylon, so I worked out a chart for Savarez Alliance. Here are the diameters in mm for a 22 from G to G:

0.48
0.48
0.48
0.56
0.56
0.56
0.56
0.69
0.69
0.71
0.71
0.77
0.77
0.81
0.86
0.91
0.95
1.01
1.08
1.08
1.16
1.16
So when ordering you would ask for HPK116, HPK116R (for red) etc. From diameters 1.01 and larger they also come in two meter lengths i.e. HPK116RA would be two meters of red 1.16mm.

This is a fairly light tension harp, about 195kg total, as is the Brittany so I think you should be OK if you have Gary’s double kit. Personally I would find the treble strings too thin for my fingers so I’d use nylon there if I could; and the last two bass a bit floppy but not too bad.

It would be a good idea, still, to ask Gary about this chart.

Best of luck with your project!

Biagio

[mae-mcallister]

Clearly I am not going to get away without telling the whole story…!

Can we just assume, for the purposes of everyone’s sanity, that I am not an idiot and I roughly know what I am doing when I mess around with string conversion equations (http://www.harpcolumn.com/forums/topic/tension-of-a-harp-string/)? I don’t claim to be an expert at all in any way (and genuinely appreciate help and input from those who are), but I also haven’t just pulled all these ideas and numbers out of thin air.

It goes like this: I have a harp kit from Gary for a double strung harp. The single strung version is designed to go from G-G. The double strung version also goes from G-G. I want my harp to go from C-C. Gary says it’s ok.

Clearly, I cannot just use the same strings as for a G-G with less tension on them because they’ll sound floppy and horrible and dull. So I have done lots and lots of calculations to figure out what gauges of string to put on my harp so that it has a similar tension as the single G-G version (in fact it is on average 0.65 of the tension of the double-strung version, when the single is obviously 0.5 of the double), this number is calculated to match the feel of my larger harp with an octave shift, which is not tension but tension per unit length, as many of you (and me!) know and Biagio has already pointed out. The result is that I have a harp which feels like my big harp but up an octave, so that I can play pretend that my lowest C on this harp is the lowest C on my large one, plus the harp has overall got less tension pulling it apart, which for a double-strung is kind of important, and my harp teacher also suggested might be a good idea. Since I am building it for the first time there is no issue of changing tension being bad for the harp because it hasn’t got any on it yet. The design of the double-strung is pretty much identical to that of the single, so there should be no issues of a lower tension sounding bad. So far so good.

The gauges I have calculated require very very thick nylon for the last four strings (because the gauges are bigger as a result of the drop in frequency), which I don’t like, makes hardware a pain in the ass and anyway am not sure it exists. Therefore I would like to put KF strings on the last four strings, which is what they do on the Bardic to combat the same problem. Using the nylon/KF conversion chart (that was super useful wil, thanks) I think I have got approximately the right diameters for the KF strings that I will need. But at this point it’s extrapolated guesswork (because my large harp is not the same material all the way down…) and it would be really really really useful to have the measurements of another harp of a similar size with these KF strings to compare to, to double check that my numbers are sensible and run some more theoretical specifications before I go out and actually order them (thanks Tacye).

So please please please please please please please could someone just tell me what the gauges and lengths of the Bardic 27 are for the last octave. I am not a child with a firelighter, I am not going to blow anything up. Seriously.

On the plus side, I am now sure that the strings are at least 1.5m long, which means I’ll only need to buy 4. Phew.

Biagio – Thanks for the tips. Why do you need the tensile strength to convert between nylon and KF (aside from making sure you’re not going to break them)? I spent a while pondering this and could not figure it out. (I spent a while messing around with Young’s modulus and Poisson’s ratio too before concluding that the change in density and/or cross-sectional area of a stretched string is pretty negligible compared to it’s length and so on…still not sure how good an assumption this is but it sure simplifies everything :S) Thanks for the densities though, that’s very helpful.

Why would a solid maple soundboard not sound good with gut? (I am interested!) My soundboard is made of ply, this if nothing else has assured me that as long as I don’t do anything wildly stupid the harp isn’t going to sound much worse or better with different strings 🙂

[Allison Stevick]

I’m pulling for you, Mae! And I’m so thankful that you’re posting all these steps, because I seriously might follow your example in the future and build my own double strung. 🙂

[wil-weten]

Hi Mae,
Above I asked 3 questions in this thread to which I still hope to get an answer. My questions may have get lost in my wordy posts above, so I will rephrase them below.

1. I still like to hear what Tim Hampson, who is helping with putting the harp together, thinks of your downtuning plans. As a harpbuilder he must be able to calculate the right strings for you. Then you won’t run the risk of ending up with an exploded harp or a harp that sounds real sad.

2. I wonder what Gary may have meant exactly with his ‘OK’ to your plans to tuning down the harp by five steps (you mentioned 4 steps, but from G to C is really 5 steps).

When I thought of ordering a 6×6 cross strung from Gary with the lowest string D below middle C, I wanted it adapted to a whole octave below middle C, so, only one step! But Gary told me I could not order that, as the harp would not sound quite a nice…

Anyway, maybe your harp and the harp I dreamt of having, are not quite compatible…

3. Why not measure the length of your strings, mention the gauges of the strings of your harp and ask Savarez Alliance to advise you on replacing the lowest nylon strings with carbon strings? You will find the contact information above.

I still am afraid it is not a good plan to use the strings from the Camac Bardic: they are meant for a quite different harp with much longer strings than your harp has on the positions you want to place them…

I just happen to know the gauges of the 3 lowest strings on the Camac Bardic 27. This is not from my own measurements, but from information from a reputable harpshop. I do hope the information I received is correct. Anyway, for a few years already, these 3 strings have been sounding fine, without any trouble, on my little 34 string lever harp that was built for Bow Brand natural gut light pedal tension (this is a tension somewhere between normal pedal gut tension and lever gut tension).

I replaced the original C, D and E wire strings below middle C for the Alliance Savarez KF-strings to get a smoother transition form gut to wire strings. The F below middle was and is the lowest gut string on that little harp. By the way, they feel like they are of a lighter tension than the neighboring gut and wire strings next to them, but this is deceptive! They are just lest stiff…

As to the gauges of my 3 carbon strings
My C27 is 1.80mm or 0.0708 inch
My D 26 is 1.72mm or 0.0677 inch
My E 25 is 1.60mm or 0.0630 inch

Have a look at the string charts of Alliance Savarez. You will notice that these 3 strings are meant for heavy tension pedal harps, not for a small 34 string harp like mine… So, these gauges are definitely not what you would expect them to be for a small 34 strings lever harp… Yet, they must be the right gauges for the Camac Bardic 27…

So, I do hope you will consult Tim Hampson and/or Savarez about your adventurous downtuning plans.

I am looking forward to your next update!

[mae-mcallister]

Allison – ta:) I’m glad that someone is finding it useful, I feel like I’m posting long-winded ramblings that no one really cares about sometimes:)

wil –

1. Tim Hampson is not building the harp. I would never ask Tim Hampson to build a harp from a kit, it’s well below his skill level and demeaning for a harp maker! This one is my fault:( I should have been more clear…the person building my harp is not a harp maker, he is a luthier (so he makes violins, violas, cellos) and his name is Tim Sparrow (http://sparrow-violins.co.uk/) and he just happens to have the same name. I’m asking him to make it because he has instrument wood know-how, plus he’s a friend of mine.

2: And I quote:
Mae: One question I have is that I have been toying with the possibility that I string the harp up F-F instead of G-G or even C-C. What would your feelings about this? I am thinking that C-C would be unfavorable because then the bottom strings would be super-thick and just go thunk and sound dull, but I am wondering whether F-F would be ok, especially as it’ll be gut strung and double too so it couldn’t hurt to ease down the tension a bit. But harpmakers always know their harps best and so I would really value your opinion on this – if you tell me that the design of the sound board is matched for G-G and it will absolutely not sound the same otherwise then I absolutely won’t do that. Obviously I’d need to decide on this before I can say what string diameters I will be using.
Gary: It is hard to say. It is usually harder to get the short strings correct than the lower strings. You have more options to work with at the low end than at the top. Some people use nylon at the top and gut in the middle and low end. Small gut strings can have problems breaking. Tension should not be a problem as long as it is similar to nylon tension.

I think that cross-strungs are a different story because they are not homogeneous so they have to be made differently if you shift them…

3. Because I don’t actually have the lowest strings in nylon. The gauge of the lowest nylon strings is at the moment as theoretical as their KF replacements, because of the fact that they are going to have to be thicker. And now that I have a conversion chart it should be ok.

I am not going to use the Camac Bardic 27 strings on my harp, I just want the measurements to do some calculations and comparisons.

Thanks for the diameters, that’s useful to know. At the moment my calculations suggest that the lowest KF string (i.e. 5th C) needs to have a diameter of 1.45, so that’s heartening.

Waiting on a couple of last-ditch attempt leads, my harp teacher might know someone who has one and the people I rented one over the summer from might have a string chart somewhere…

Just to be really clear on this, I am not going to do anything rash. The more info I have, the better chance of me getting it right…

[Biagio]

In reply to Mae’s questions on my comments…

First density and why the tensile strength issue:

Well, clearly Mae understands the Taylor equations so I won’t get all mathematical here (grin). When I sit down to a new string design I have three things in mind (usually): tone/color, even feel, and (ideally) no big jumps in diameter. Obviously I don’t want strings breaking but equally as important to me I don’t want some to feel and sound like bars or rubber bands.

That’s where the tensile strength comes into play: in general (NOT always) if a string is much below 30% it can sound rubber-bandy (and if too thick like a bar). So really I’m looking at four parameters in relation to the entire band: tension in lbs. or kg, %tensile strength (%T), the ratio of %T to length (a surrogate for resistance or “stiffness”), and the diameters. Tensile strength will be a factor in the last two.

Why might not the maple board sound good with gut or fluorocarbon? Becuz….it is quartersawn 1/4″ thick rock maple with the grain running vertically. I’d worry about it splitting (too much tension) or sounding dull (too thick for the gut strings). Sounds fine though with FC, which has similar physical qualities to gut (another grin).

Cheers,
Biagio

[Biagio]

With respect to KF vs nylon and diameters: The problem I’d be having here is that while I can play around with compositions the length is fixed and therefore so is the percent of tensile strength for any given type (nylon, KF, gut etc.) no matter what the diameter.

1.80mm is a good size for that low C but at the LENGTH designed for a G it will sound dull, guaranteed. To give a more specific example by messing with my rental design:

The ow G is 24.75 inches; with a 0.060 nylon the relevant numbers are:

tension 26.5lbs %Tensile 21 Tension/Length 1.07

That’s as low as I’d find acceptable even in an inexpensive harp like this.

KF at 1.35mm (0.053″) costs more and does not get me a whole heck of a lot in terms of relative “floppiness”:

tension 30 lbs. %Tensile 23 Tension/Length 1.27

OK, so what happens if I drop the range 4 steps to C and find the KF diameter that will get me something acceptable? With 1.80mm (0.71″):

Tension 24.1 lbs. %T 10.2 T/L 0.97

Rubber band with that %T, I’m afraid: wound steel/fiber/nylon would be my choice. It would e skinnier too.
Biagio

[wil-weten]

Hi Mae,
Thanks for enlightening me. Now I understand better how you plan to adapt your harp.

I get the impression that Gary’s answer to your plan to lower the range with one step or even five steps, is “It is hard to say”… instead of “OK”.

Why would a 6×6 cross strung harp be less “homogeneous” than a one row or two row harp of about the same dimensions?

By the way: this may really interest you: the Stoney End 5×7 cross harp Esabelle goes only down to G below middle C. The same harp, but made with a 6×6 division goes down to D below middle C. But lowering the harp with one step to C below middle C would not sound nice, Gary said to me.

Now, before you think that on your harp a D below middle C is possible: the cross strings of the Esabelle are somewhat larger than those of the Brittany. And both the 5×7 as well as the 6×6 version sound really nice for their size. You can find its dimensions on the internet. I found a picture with the small harps next to one another on http://www.minehara.com/stoney/images/stoneycatalog1.jpg

[Tacye]

(in fact it is on average 0.65 of the tension of the double-strung version, when the single is obviously 0.5 of the double), […] The design of the double-strung is pretty much identical to that of the single, so there should be no issues of a lower tension sounding bad.

Just picking up on this where it reads to me as though you aren’t being clear between the total tension on the harp and the tension on a string and how each affects the sound and the harp.

For reference, my Eve currently has a total pull of 280 kg on it – I can’t find the figure for what it had with nylon.

Biagio, is there a reason you are suggesting steel cored wound wires? I would have inclined towards fibre cored wires for a more even sound. Mae, Salopian do custom wound wires if you want anything special.

[Biagio]

Tacye,

Yep on the first…one cannot (or at least should not) consider each string in isolation and this is especially true for a double strung harp. If anyone has ever tuned up a double from the first stringing they will be well aware of how absolutely awful it sounds at first. Tune the string on one side and three or four adjacent ones immediately go flat or sharp!

And once the thing is holding pitch (finally!) they will notice much more sympathetic vibrations than on a single strung. So it is quite important in the design not only to consider the total stress but the relative tensions and color across the entire band.

About metal core versus fiber core in the bass….I agree that if the lengths work they would be preferable to SFN or SFB. As a matter of fact I do think fiber core silver wound would work in this case.

You have more flexibility in design with metal core, though, as steel does not stretch (much!) and is not as brittle as bronze. But artificial silk keeps stretching forever.

As a general rule we don’t want the fiber string’s initial percent of tensile strength much greater than 50-55% nor lower than 30%, and in addition they cost a lot more. Mae’s Stoney End harp is not a particularly expensive one – small range, ac/c ply soundboard, laminate box sides – so I’m not sure she would get that much richer sound from the fiber core.

On the other hand, with rather heavy fiber bedding over a thin steel or bronze core you can get an acceptable transition at lower cost. That’s what my teacher and I ended up doing on her prototype double 26. We figured “Hey, let’s save some money and see how it sounds once it has settled in.”

Pretty good as it turns out, but we’ll make some more changes on the next one, for sure:-)

Cheers,
Biagio

[Tacye]

Ah, I didn’t think of price as Salopian charge the same for the two cores. Can you share a cheaper source of steel cored windings?

[Biagio]

Tacye, I buy my wound strings from Vermont Strings (a member of Robinson’s Harp Shop) in the US so I can’t say what they might cost elsewhere. At lengths over 40″ they cost the same, metal or fiber core.

Right now I need to get rid of some harps. This little apartment is getting crowded!

Anyone interested in a Clark Model A in excellent condition????

[mae-mcallister]

Thanks guys, you’ve given me lots to think about!

wil – sorry, was thinking of a 5×7!
Tacye – generally thanks for all the info
biagio – you’re incredible. see the other thread…also, 1.80mm is on the Bardic, not for my harp!

Everyone – I got the measurments! My harp teacher managed to borrow a bardic from one of her students for the day so I ran over there armed with tape measure, piece of string and micrometer and I know have all the gauges and lengths:):):):):):) If anyone is reading this in the future (I mean, the not-immediate future) because they’re looking for this info and have found this thread, message me. Thread solved.

Everyone else – nice website explaining all the randomn stuff we’ve been chatting about here: http://www.sligoharps.com/string.html if you’re interested and/or bored and/or confused.

Thanks everyone! Will let you know how the restringing calculations go on the double-strung saga thread.

Mae xxx

[mae-mcallister]

Well, I’ve learned a lot about tensile strings and string materials in the last few days! Thanks for bringing it to my attention, Biogio, it was a real education, and now I understand more why harps are strung with the materials that they are strung with and also why KF won’t work in this instance. I have a few very beautiful graphs now and the info on the bardic was very very helpful. To the steel/bronze wrap strings…

Tacye – do you know of any one/where in the UK that would do phosphor bronze with nylon wrap strings? How low I decide to make the harp really now depends on how many of these strings I think I can afford. If I asked Cambridge music gallery to get them in (which is incidentally a) round the corner from where I work and b) where my luthier friend who is building this harp works part-time:) I’d need to give them a supplier name…?

Biagio – how did you factor in fibre to calculate string tension? I have an equation for the tension that includes a correction for the wrap but I’m not sure how to include the fibre wrap…what’s the density of the fibre? And how does its thickness generally affect the sound? I’m curious.

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