So what is it, metallurgically and mechanically, that distinguishes historical brass wire of the harpsichord from modern industrial brass wire? I’ll just restrict the question to yellow brass for now, to avoid going off on a tangent about red brass, just to limit the discussion.
For example, how is Mr Birkett’s wire different to Little Falls?
HI Andrew, you will never get a quantified answer to your question. Stephen Birkett decided not to publish his data sheets for wire, perhaps Little Falls will do. But even then: a data sheet cannot describe the refined characteristics of a certain wire.
It’s like the Christmas cakes of our grandmothers: even if they happen to use the same recipe all of them will be slightly different.
Long time ago I considered wire as an homogeneous material, made up of a mix of several ingredients, copper and zinc for yellow brass. Looking further we will discover that the material is spiced with other materials too, e.g. iron, tin, aluminium, but also carbon, phospor and many other things could be found. This simplistic view will help to describe the difference between iron, red or yellow brass.
Later I learned that strings are chrystaline: it’s worth looking at a string through a microscope, one could then easily discover the richness and variety of the metalic chrystal structure. Being Dutch a have skated hundreds of kilometers over frozen ice: lakes, canals, even rivers. Every meter was different, the crystal structure of frozen water is fascinating, and never the same. So are wires. The crystal structure of a certain wire not only depends on its ingredients, but also on the way the alloy is produced, and the wire is drawn (think at the famous tensile pick-up after drawing). The conditions and speed of heating and cooling down will determine the structure also.
I would define historical wire as wire made before ca 1830: that is metal (or ore) melted on a woodfire. Strings made after that time are typically made on a coal fire, so at higher temperatures. Mr Birkett made an effort to reproduce the historical wires, leading to a higher amount of phosphor and lower amount of carbon in it.
Finally there are differences in various thicknesses produced, as well as in finishing. E.g. Birketts wire has a coating to prevent it from rusting. Reliability and consistency is also important: if a string is not perfectly consistent in its thickness or components it can never be well tuned.
Producing harpsichord strings is an art which cannot be summarized into a few figures. All wires are different and will only yield a good result if they are well matched to an instrument, the repertoire to be played and the sound ideal related to it.
After 15 years of research I have answers to these questions about historical brass music wire. I have resisted giving premature results and piecemeal explanations along the way. I am confident now the brass wire I supply is the same as historical brass music wire. And it is quite different from everything else available, which is all modern industrial wire.
Everything discovered will be published soon.
Just to correct a couple of points in PK’s post…
As I said in my prior reply, everything from my wire research will be published and there will be no secrets. Soon now.
There is, and never has been, any coating on the historical wire I supply. The alloy composition of the iron gives it a natural corrosion resistance.
Thank you for your additions Stephen. We are looking forward to your publications.
I already said I am asking about yellow brass not iron. And I am not asking about gauges, but about metallurgy (and I do know that drawing to a size affects hardness). Student did not read question 
I am aware of extra atomic elements in brass. But what do we know about historical brass in this regard?
It seems to me to be easy for people to diss modern brass without being able to say in scientific terms what is is about alleged historical brass that makes it superior.
In terms of materials, which is what the topic is about, given that we have very little choice in brass now as Domenico always points out, by what criteria do you ‘well match’ wire to an instrument (and again, I am not talking about gauges and tension, or the transition to red brass)? Seems to me there is only Rose wire, and the two from Vogels, and essentially nothing else.
The third and valuable option is the historical brass wire by Stephen Birkett. I believe the 6-octave Dulcken piano in our concert hall in Holland is the first instrument ever strung with the thicker gauges of this material. It is just wonderful: a clear sound with much presence and also easy and stable to tune. The instrument has been used by several professional pianoforte players with great success.
Yes it is wonderful. I wrote here on Jackrail my impressions after a complete restringing of my harpsichord. Stephen’s help in establishing a new and more appropriate stringing schedule was also invaluable.
I just hope Stephen can soon establish a strong production and commercial framework so that he can provide plenty of strings to every maker/harpsichordist. Or, just wait he publishes his researches and results along with a detailed how-to procedure.
I have used the Instrument Workshop yellow brass on several clavichords and I very much liked the result; sad to say it was better than Malcolm Rose’s, by which I mean (approximately) better sustain and a better balance of partials with no perceptible inharmonicity. At the time, Stephen’s brass was not available. I have the impression that IWS brass is essentially the same as Zuckermann brass, but wire suppliers have hitherto been rather reluctant to disclose precise details of the origin, composition and drawing schedule of their wires – with the honourable exception of Vogel. I applaud Stephen for now promising to give this information.
Incidentally, I think the terms ‘Stollberg’ and ‘Freiberger’ etc. are simply names given by Vogel to different kinds of wire; I don’t think they are the names of manufacturers. I have assumed that Vogel draw their own wires. Is this the case, does anyone know? At any rate, I did not find the Vogel wire performed as well as IWS brass, despite its being much cheaper and easier to obtain when the UK was in the EU.
I hope someone can rescue the IWS.
Stolberg at least is a wire making company:
Well if that is the case, as I have long suspected, then now that we know that Zuckerman’s is just a standard spec Little Falls alloy product (perhaps to a custom tolerance, maybe) then the Instrument Workshop wire is not something custom cast for IWS and is also a stock product.
Now we are getting to the bottom of things, across a couple of topics here on the forum.
Andrew:
Well if that is the case, as I have long suspected, then now that we
know that Zuckerman’s is just a standard spec Little Falls alloy product > then the Instrument Workshop wire
is not something custom cast for IWS and is also a stock product.
I think ‘stock’ might be a slightly misleading term. I have commissioned
wire from Little Falls in the past: they draw for each customer,
according to the required specification, which is why there is a minimum
quantity for each order. Of course there are standard terms for things
like alloy, temper and tensile strength, otherwise it would be hard to
explain to them what it is you are asking for; but LFA do not supply
wire from stock.
@Peterclav yet more excellent info.
It seems I am not the only one struggling with a definition of the sound from “historical wire” and modern versions. One problem is that I perceive that there are a lot of “subjective” evaluations.
Let me stick my neck out and ask/explore what we know about the physical properties of strings (let’s be limited to the brass-types for now?). Although my expertise is not in Material Science I have been exposed to metallic micro-structural issues in my profession (related to mechanical failure analyses). After all, the problem is really one of mechanically excited sound waves in a gaseous medium.
To start a discussion, let me wager an opinion regarding what might lead to a “good” wire for harpsichord applications:
I ”hear" comments along the lines of “dull” response versus “brilliance”. I would think that dullness says something about the damping characteristics of a wire (apart from the damping due to the surrounding air), or a relatively fast decay of the high frequencies, whereas a brilliant response might be associated with a longer sustenance of the high frequencies. Has anyone made comparative measurements of the sound decay rate of wires of interest? Is there any one in the Jackrail group who has measured/compared frequency spectra for different wires at a fixed frequency (or the same for several frequencies)?
I can readily understand where a knowledge of the micro-structure might have a lot to do with the physical properties of strings affecting their frequency response. And not only the average state of the microstructure, but its distribution: After all, the internal structure would be expected to vary across the diameter, because the most intense “working” of the wire would be near its surface as it is pulled through the die, and that surface-near region would, consequently, contain the smallest grains (unless the last production stage is a complete annealing). The wire is, after all, a collection of metallic crystalline grains of the metallic (and non-metallic) components, interlocked with each other through non-crystalline “boundary domains". And the size scale of this mixture changes as one moves from the surface of the wire to its interior. I would venture to believe that these non-crystalline boundaries are responsible for a lot of any damping and thus important in the frequency response of a wire.
Does any one know what the possibility is to obtain a short piece of “historical wire”, say 1-2 cm long (how would one know whether it was really a ”good” wire when it was in service)? If that were available one could could examine the microstructure by successively slicing/removing off thin layers parallel to the wire axis on one hand, and transversely (cross section) on the other, for observation under an electron microscope. This would needed to be done along with a chemical analysis of all the elements present. The results would have to be compared to the identical process on a “modern” wire (of same diameter). While I do not have the capability to execute these tests, I have either colleagues or commercial laboratories, where it only becomes a matter of funding, which I have not yet explored (first want to know whether that might be feasible). Who would make the auditory evaluations of such wires?
Too complicated and uncertain?
In the meantime I’ll pursue options for electron microscopy, locally.
Wolfgang
Wolfgang, I believe Stephen Birkett, who is on this forum, has made all this and a lot of other measurement.
I believe Stephen has made analysis on antique steel (or iron?) and brass, both on objects and on remains of antique strings that can be found on certain antique harpsichords. I am not sure about that he could make such analysis directly because the harpsichords with remains of strings are usually in museums whose directors often don’t allow such examinations. However there is the old book by Martha Goodway and Jay Scott Odell who were able to examine pieces of strings (don’t know how good their research is by modern criteria).
A couple days ago Stephen wrote a thorough publication is due in short time, so we’ll know everything. In the meantime he may want to clarify your (our) doubts, without going too deep.
I have read this exchange with much interest. Perhaps I missed it and it is somewhere there? What I read a long time ago was a very simple description of the difference between modern and historical wire, according to which, say, brass wire is made by producing an alloy of very pure copper and zinc, while historical wire was made by mixing reduced copper and zinc ores that still contained a significant amount of other metals: this would make the alloy stronger and the sound different.
Typical compositions of modern red brass and yellow brass have been described above. I would be very eager to know, acknowleding the existing variations, the composition of typical equivalent in, say, 18th century wire.
@CDV This is what I have been asking and nobody so far can say.
It occurs to me that 18C, say, brass wire was not made specifically for harpsichords, but had a hundred industrial and trade uses. I even read an article from a Copper Alloy Association site that had a short essay about how brass wire was used on cards used for carding wool, a very important application. The point being there are likely to be many sources of old samples apart from the microscopic bits left on some instruments. But I guess metallurgical specialists don’t have so much interest in historical factors, preferring to concentrate on refining and improving the modern products. Interesting thought. And brass wire has been made since Egyptian times so there must be samples, and possibly analysis of very old wire.
There are still six or seven other atomic elements commonly found in modern brass, by the way (I think I linked this earlier). So it’s not a matter of new brass being ultra pure, but the precise amount of other elements and so on.
Just adding the link again here.
Both bronze and brass may include small proportions of a range of other elements including arsenic (As), lead (Pb), phosphorus (P), aluminium (Al), manganese (Mn), and silicon (Si).
That is referring to modern brass.
Peter, if you don’t mind telling us (i.e. if there is no secret to safeguard), may I ask:
Thanks in advance.
I will answer from memory if I may, since the workshop is closed and
records locked away elsewhere, and it would take a long time and big
effort to find the details of my original order.
As far as I recall, then, the minimum order was 10 kg. I ordered 85/15
brass in two specific gauges, to complement the wire I already had in
stock from IWS. I asked for ‘HARD’ temper: from memory there are two
grades harder than this. I was required to specify tensile strength in
MPa (mega-pascals); I aimed to match the tensile strength of the 85/15
wire in my existing stock, having broken samples of adjacent gauges on a
primitive rig using a spring balance.
The wire was excellent; handled well and sounded well. I spooled off
some (laboriously) to supply other makers, but I still had lots left
when I closed down.
Hope this is helpful. The main problem is the large quantity you have to
order.