Double-strung harp saga

[Tacye]

I would go with a needle file, hand reamer or burr grinder – I feel more control of rigid tools than flexible ones.

If the harp will take it I would try increasing the tension on the woody side without letting the strings get thick enough that you don’t like the sound. For some, moving the strings you have up the harp may work (and you have the wrong thickness blue ones to play with even if it is the wrong colour for where you try it) – you may well want KF or more wound strings.

[mae-mcallister]

Allison – excited! You are welcome to continue on this thread if you wish, it is about the same harp after all:) If you do decide to go with the lower range, I can send you my (tried, tested and refined:) string specs so you know exactly what to order. The only difficulty will be drilling out the eyelet holes to accommodate larger strings. As I said, we managed in the end so it is possible but does require some thought (or you get Stoney to do it for you beforehand…). Were that not the case (and assuming I can iron out the string problems) I would recommend the C side without a second thought, it is incredibly liberating. Would you be interested in a video soon, even with the current crappy strings and down one string? Otherwise it’ll have to wait until I can get the wound ones…

Tayce/Balfour – hmm, needle file. Tim has one (I broke it…a bit…just the tip…in the eyelet adventure :O) The strings are already too thick! My plan for the top five is going to be to try KF, it’ll be sooo much thinner and slightly tighter, so it might end up being a bit better (KF has an enormous 2% increase in %TS from nylon…I know, shockingly huge, but you never know:) The rest will have to be wound.

Wil – your harp friends have not replied to me yet. Grr. I sent them another message, this time through their website. Maybe they don’t speak English? I can’t speak Dutch. I can rewrite my request in French, Hebrew or German at a push but I’m not sure that’ll help:) Ooh I could probably do it in Latin too. Less helpful. Why are shops so pants at replying to emails?!

I have come up with a wound string design for the rest of the strings. Interestingly, I had to remeasure the entire harp because it’s shrunk about 2cm since I strung it up!

[wil-weten]

Hi Mae, I have no idea why this reputable Dutch little harpshop has not yet answered your mail yet. I can’t imagine their English wouldn’t be well enough to understand your questions and reply to you within a few days or a week. And even if English were a problem, they undoubtedly would have friends and acquaintances to help them out. Or maybe they have been abroad to select some new fine harps to sell?

Do I understand correctly that the soundboard already has developed a 2 cm belly?

O, and I am really interested in a video of your playing the harp as it is now (with the dull strings on de lowest strung side!)

[Biagio]

Here we go with another US source (sorry I don’t know of any over the pond). For Z pins with enlarged holes:

http://www.harpkit.com/mm5/merchant.mvc?Screen=PROD&Store_Code=MK&Product_Code=zpinlg&Category_Code=supplies

I too am really looking forward to hearing the final result!

Biagio

[mae-mcallister]

Mackays sell single round needle files for £1.50. I AM SO THERE. Forget the cord.

Wil – god no! The whole structure has tightened up. No belly noticeable, although I’m sure is probably not as flat as it started out, like any harp.

Video coming up…at some point.

[Allison Stevick]

Yes, yes! Video as soon as you can! 🙂

[balfour-knight]

Hi, Mae!

So glad the file idea is working, and thanks to Tacye for giving us the correct name “Needle File.” My dad had wonderful tools and could fix anything, but I did not always know the correct names of them!

I wish we lived close enough to you so that my wife and I could pop over there, put the kettle on, and have a cup of tea with you. We would bring all our harp supplies and try different sizes/types of strings on that harp until something sounded great, ha, ha!

[Tacye]

I am unconvinced by the percentage of tensile strength being a fundamentally relevant metric or of more than serendipitous relevance when swapping between similar materials: a way of normalising tension for cross sectional area. You aren’t breaking the strings, gut is in its elastic region and nylon creeps a bit but is pretty near elastic and you are far from the failure point.

[Biagio]

%TS is probably not a useful metric if we are discussing gut strings on a higher tension instrument. If we are talking about a lower tension harp, as is the case here, it is very relevant for the reasons I outlined. If you wish to convince yourself, replace your pedal gut 4th octave A string with a nylon one of let us say 0.8mm.

Biagio

[Tacye]

You don’t get my point Biagio – you gave a rule of thumb for considering a string’s length and pitch. You did not provide any support for choosing the absolute strength of the string as a normalising constant especially when changing between materials. If I doctored a string to be weaker without changing its mass or elasticity would the sound change?

[Biagio]

You are correct Tacye that I do not “get” your point. This is because, if I understand your post, you are saying that the string’s tension with respect it’s breaking point is irrelevant. If that is not your meaning, I stand confused. If it is your meaning I stand here amazed. I am not interested in going to the trouble of providing support for my discussion of vibrational physics here. You can look that up on your own, it has been very well studied.

I have no idea what you mean by “doctoring a string” so let me give you a rule of thumb: if you design a harp string such that %TS is below about 15% it will sound like sh*te. On the whole, after over 10 years of designing harps, from therapy to concert tension, I rarely allow anything under 30%. How bad will depend in part on it’s length but it will not be good, I guarantee you.

If you disagree that is fine, but I would not want to buy your harp.

[Tacye]

Biagio, may I ask how much physics you have studied? I am wondering if my point is too subtle in distinguising between a rule of thumb and the appropriate physical quantity. I might for instance say to stay your car length from a particular cliff edge – which could be a good rule of thumb. The point I am making is along the lines of if you go away and buy a really short Smart car the cliff doesn’t get safer – because the rule of thumb was related to a car length being conveniently known, not an intrinsic property of your car.

The breaking point is relevant when we are breaking strings, so for calculating maximum string length for a given pitch. Well below this tension the breaking point is just a conveniently known constant for generating a rule of thumb for the lower limit of sounding OK.

[Biagio]

Tacye, since you ask, my familiarity with acoustics includes some eighteen years as a signals intelligence officer, and with respect to physics studies they were required as a graduate student in marine ecology. What then is your own? Frankly I rather think that comparing notes in this regard is pretty childish, as is your automobile example. I could as readily ask you how many harps you have made and for whom but I am really not interested.

I have previously pointed out that – in layman’s terms – when a string is too loose for the frequency the vibrations are unstable. That can be calculated for a given material length or frequency. Personally I don’t know any experienced harp maker who does. But the physics is undeniable, As I said, I am not going to sit here and waste my time performing a calculation to prove the point.

I’m done with this, it is too irritating to debate an obvious and self evident observation.

[Tacye]

I am sorry for letting my enthusiasm for finding people with some interest in the science of strings take me too far in a direction you are not interested in. I can get overenthusiastic about things – in this case the boundary between scientific theory and craft knowledge or ability and delineating which is which. I apologise for questioning you – but you seemed to be completely missing the point I was trying to make, and I couldn’t see why – maybe the issue is ‘two countries divided by a common language’ and the flavour of our scientific experience is different. I respect your craft knowledge of having designed harps from scratch that work (I have never done that though I have changed stringings and must someday finish the one I put a new soundboard on) but can’t stop using my physics training (PhD) and questioning the deeper reasons behind effects.

[Biagio]

And I should apologize for my grumpy response! Put it down to an elderly gentleman with an aching back today. Reviewing the previous posts I do indeed think we were probably writing at cross purpose. If your point is that TEN% (below a practical maximum of say 95% for a concert harp) is not a particularly useful metric compared to others for a well designed harp I do emphatically agree.

But let’s stay within the context of the thread. I think it is pretty cool that Mae has taken this challenge and come up with something workable. But with all very sincere respect I’d venture to say that Gary’s small harp INTENTIONALLY strung to the low C range as here would not fall in the category of well designed. This is not to say that it can not be done but there will be trouble areas if we keep within the designed tension limits and string materials. Where are those trouble areas likely to be on that “C” side?

From what I have read of your writing I think you could have predicted them; my prediction would have been some of the bass strings which would be too thick to be comfortable and some in the mid with nylon mono filaments where (here we go) %TEN drops down below 20%. And the “why” of that is that we will experience some wow and flutter, or to be more “scientific” the signal starts to become chaotic. That is actually one of the techniques for voice encryption/decryption but I better not say more in that regard:-)

That analysis gets extremely complex and as a practical matter why bother? If we as harp designers set some heuristics AND test them we’ll come up with designs that work with a lot less effort:-)

But let us not deny that there will still be effort. Last year I designed a double strung for Laurie Riley – we went through at least five iterations before she liked it; and then we decided to make a different one in walnut. One of our “problems” during these iterations is exactly what we are discussing here. She wanted a particular tone and a particular size (which translates to string lengths) and a limit to the weight. Despite one of the Fs being within my heuristic, it still was too “woody” as Mae describes it (i.e. low TEN% )for her extremely acute ear. The only solution to that without using wound strings (which she did not want in that range) was to beef up the weight of the neck (which helped to absorb those excessive vibrations).

Of course she is also my friend and my teacher so I didn’t mind, but it does illustrate the joys and frustrations of custom design. The salient point being that theory is useful and helps me avoid some pitfalls but I don’t really KNOW how it will sound until I’ve built it…and quite possibly not completely know for several years:-)

Anyhow, I trust we are on the same page now. I am curious though, what physics training you had as a psychologist – or was it ancillary as was mine? I’ve found the harp to be a fascinating adventure and really do enjoy exploring design questions; I wish more musicians did!

Biagio

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