S&S capo - Œstring noise¹

[Ron Overs]

To the PTG list,

Having experienced the same symptom Christopher Purdy describes on other S&S Ds, and having rebuilt quite a few Ds with similar problems, I expect the problem that he describes at D52 will prove (in my opinion) to be symptomatic of a carelessly shaped, large radius capo bar.

Note D52, the first note in S&S D capo sections, is often poorly shaped and of a larger radius than that of the main body of the bar, since it is located directly adjacent to the plate bar between C#51 and D52 (where access is difficult). In 1985 a new Hamburg D was shipped to the New South Wales Conservatorium of Music, for the Sydney International Piano Competition of that year, with an extremely Œnoisy¹ D52. Similarly, the large radius and poorly shaped capo bar was almost certainly the problem with that piano (in my opinion).

As a general observation, the capo and front duplex radii (and their lack of hardness due in part to improved foundry practice - longer freezing times yield softer but less-distorted plates) appear to be the principal factors contributing to Œnoisy¹ duplex sections in pianos of recent years. The duplex lengths can also be involved, as they are invariably too long. Try pressing a heavy piece of cast iron or steel onto the front duplex strings of a Œnoisy¹ note (quite close to the duplex bar), moving it gradually towards the capo while firmly striking the note. The tonal quality will often improve as the effective duplex length shortens. You cannot use your finger for this test (but you wouldn¹t want to, would you?), since the high hysteresis loss of flesh will quickly absorb the energy of the speaking length as it crosses the capo to the duplex length. In many examples, long-duplex Œnoisy¹ sections can be Œimproved¹ by installing a pressure bar (with a very low pressure angle) between the duplex and capo bars.

We have been reshaping capo and duplex bars to a small radius since 1988. We have been hardening cast-in capo and duplex bars since 1994, ie. after reducing the duplex height (when excessive) and the apex radius. The sectional bar-shape is also modified to facilitate the application of the treatment process. When rebuilding european style grand pianos with brass bearing bars (eg. Grotrian and Bluthner), we replace the bars with profiled and hardened steel bars. I have no problem altering a piano if it Œimproves¹ its performance. If clients feel uneasy about this they are always free to choose another repairer, where existing Œfaults¹ may be reproduced in all their splendour.

Please turn your web browser to our site at www.overspianos.com.au (home page). The 1996 rebuilt S&S D shown has reduced height front duplexes. The string approach angles, originally in excess of 20 degrees, are now under 15. If you check this jpeg image at note D52, you can just see where the original duplex bar height was reduced. Individual rear duplex blocks (not standard S&S) are also visible in the top right corner of this image - these are tuned when the piano is tuned, in the same manner as in Fazioli pianos (we have three rebuilt Ds with individual-tuneable rear duplex blocks in commercial service). Please excuse the hammer alignment of note E80 in the jpeg image (it is too far to the left). This photo was taken some months after a regulation.

The front duplex remains an area where much research is needed. I¹m not enthusiastic about the latest trend of using phosphor bronze for capo/duplex bars. On high-use commercial pianos (ie. frequently tuned) these are subject to the same string damage as unhardened cast iron. Our heated treated duplex and capo bars are hard enough to deform Roslau wire (nominal hardness of 45 on the Rockwell C scale) without marking the bar. We hardness test bars after heat treatment by placing a test length of piano wire over the bar, moderately striking it with a hammer to test relative deformation). These bars facilitate the production of new piano Œclean¹ tone for much longer in commercial use. While you might feel concerned about the service life of piano wire over these bars, the Œstring life¹ has proven satisfactory provided that technicians avoid Œswinging on the tuning lever¹ too enthusiastically while tuning. We have concert instruments (with hardened bars) which are approaching their sixth year under conditions of heavy commercial use without any string breakages.

In conclusion Christopher, If your client¹s D was under our care we would probably not hesitate to recommend that the offending capo and duplex bars be reshaped and the relevant sections restrung. But you must be sure that you are making a correct diagnosis before undertaking such a repair. Don¹t automatically take my advice. After all, a senior Hamburg Steinway representative (Mr W Husmann) stated in a report (dated Sept. 16, 1996) that I ³. . .[do] not understand the design of a Steinway piano at all². My 17 page response (the details remain undisclosed at this time) dated December 9, 1996, was the last correspondence I have had with S&S Hamburg.


Regards,
Ron E. Overs.
Sydney, Australia.