beryllium copper on the front page

© Tilman Skowroneck 2012

As the “searches” tab in my blog stats is telling me, many people are interested in the characteristics of  beryllium copper harpsichord wire in comparison to other materials. Some time ago, I have posted an explanation in the “Skowroneck harpsichords” tab of the sidebar (see my full text there), but I would like to pull the discussion to the front, and expand it.

As I have stated, beryllium copper is not the same as phosphor bronze (the latter doesn’t sound all that well, hence this whole discussion) although it looks very similar. It has similar characteristics to brass and can be used in harpsichords with a brass scaling, or in the bass of harpsichords with a mixed scaling. I also claim that,

beryllium copper of the kind best known to me also has a good sound. True, most people will have no possibility to make direct comparisons between the various materials – and “good” is a problematic term. I have tested brass and beryllium copper in one single instrument and monitored their properties over a time span of 15 years. I found beryllium copper to sound slightly “fuller” than the brass that is usually available today, but without compromising the appropriate overall “brassy” sound character. Together with the advantages listed above I personally prefer this material. As said above, however, these properties may vary from manufacturer to manufacturer and not all beryllium copper appears to be as good as I describe here.

I am re-posting this here, because I should add that beryllium copper can be hardened just as other wire. This property might in fact be at the bottom of some negative judgments about its usefulness as harpsichord wire. The quality available to me has a beryllium content of 5 % and is called “1/4 hard,” which in my experience translates into a breaking point just slightly higher than the various kinds of brass that many people use in their harpsichords. This is the material which has the properties I have described above. For problematic spots, I also keep a few strings that are called “3/4 hard” – they do hold better, but they also sound more metallic, lacking some of the depth of the others.

Now I am told that simple oven-hardening increases the rupture strength of beryllium copper so it comes close to soft iron (I have not tried this. I am using my oven for other things). The problem with this is that ferociously hardened beryllium copper strings sound truly horrible. It results in a lot of overtones and a clear metallic “punch,” but there is no substance to the tone. Truly and thoroughly hardened beryllium copper is not useable as musical wire.

To discuss the usefulness of the useful kind, that is, not-very-much-hardened beryllium copper, one can consider this:

  • To people who are applying rigorous historicizing standards, beryllium copper might not appeal because it is unhistoric (it is, however, good to remember that even most available brass is dissimilar in many ways from historical brass).
  • For those who are bent on finding a “better tone,” it is important to know that beryllium-copper is not some kind of magic material that promises instant improvement, it is just simply one of a bunch of possible choices of string material.
  • Beryllium copper strings are ridiculously expensive. My second point implies that a harpsichord maker who does not want to spend that kind of money is not losing much for not trying.

In conclusion, the discussion of the presence, necessity, or merits of beryllium copper strings (in general or in a given harpsichord) is not a great candidate for quick knee-jerk assessments, it is not even a good place for agreement or disagreement. It is a matter of knowing what you’re talking about (I say this, again, because phosphor bronze looks so similar), and of careful observation and listening.


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