Preservation of Wooden Musical Instruments


Figure 3: Bach-Cembalo, Kat.-Nr.: 316 and Copy, Kat.-Nr.: 5614
© Musikinstrumenten-Museum PK, Berlin / Photos: Jürgen Liepe

Zither by Friedrich Idinger

Zither-resonance table

Endoscope video of the zither-resonance table


1‘ flash-talk for WoodMusICK

Brussels conference – Preservation of Wooden Musical Instruments Ethics, Practice and Assessment, Musical Instruments Museum, Brussels, 5-7 October 2017.

Preserving Sound – Musical instruments and their ephemeral feature: Possibilities to deal with it

Tom Lerch
Musikinstrumenten-Museum, Staatliches Institut für Musikforschung Berlin, Germany

Extended Abstract


Sound is an integral part of musical instruments and is of essential importance concerning the readability of these objects. Preserving this aesthetical aspect is a special challenge. Some possibilities are described in the following: from keeping the originals ‘alive’ to high quality recordings.

1. Introduction

Sound is an integral part of our inherited musical instruments. These are functional objects, which belong to our cultural heritage not only because of their artistic design. They are complex constructions and their acoustical properties are an absolute essential part of their aesthetics. Restricted capability of sounding necessarily leads to a restricted readability and so reduces the cultural, social and scientific value of our objects. What are our means for conserving this aspect of musical instruments and how do we conserve sound?

The look at some musical instruments - keyboard and woodwind instruments of different types - and their historic and actual use in museums and collections, instrument copies and their associated concepts as well as recordings of different ages will create a representative cross section of our efforts to preserve sound since the founding of the great musical instrument collections.

2. Methods

In attempt to find a solution, to enable also following generations to experience the ephemeral sound of music and musical instruments we have developed some methods during the last century:
- preserving the instruments as tools in playable condition
- manufacturing reliable an true copies of the tools
- sound recording and distributing (hopefully including conserving the recordings)

3. Examples

Following there are a few examples of projects we realised during the last decades.

3.1. Playing Musical Instruments

Traditionally the first way to preserve sound is to obtain the playability of musical instruments. Conservators try to find a balance between conservation and using suitable objects. Even as this might not be the ultima ratio in any case – as the condition of our objects, the wear and tear in use or the acoustic quality make playing historic instruments highly questionable – it may deliver satisfying results in some cases: For example the Mighty Wurlitzer Theatre Organ of the Musikinstrumenten-Museum PK, Berlin, which is regularly played during guided tours, concerts and cinema events.

There is a lively scene of theatre organ enthusiasts and many of the still existing originals are still in playable condition. For this purpose nearly every wearing part is in production in good quality today. And from a technical and aesthetical view these parts are very close to the originals. Even better, these organs were made for heavy use and therefore they show reasonable wear and tear.

Figure 1: The Mighty Wurlitzer, Kat.-Nr.: 5369 © Musikinstrumenten-Museum PK, Berlin / Photo: Jürgen Liepe

3.2. Copies and Originals

There are many conservational and technical reasons for originals not to be held in playable condition. An alternative solution is the production and use of copies of some musical instruments of special interest, just as well as the use of copies of functional parts.

To the collection of the Musikinstrumenten-Museum PK, Berlin, belongs a famous harpsichord, which assumedly has belonged to Johann Sebastian Bach: The Bach-Cembalo, Kat.-Nr. 316, made by the Harraß-workshop, Großbreitenbach (Thüringen), around 1700. After having suffered from WWII and of many years of use, it was in no playing condition any more. A restoration to a playable state would have demanded heavy intrusion into the original substance. Also there are several traces in the construction of the harpsichord, which document very early and fundamental alterations by the maker: two different stages of development caused through musical requirements and use. In the 1990s as a consequence it was decided to conserve the original harpsichord in its impaired state and build two copies: each one representing one state of construction. Both of these copies are made to be played and enable the musicians as well as the audience to experience the sound of the Bach-Cembalo as it must have been during the times of its use.

3.3. Sound Recordings

In 1890 the parish of St. Wenzel, Naumburg , sold 37 historic wind instruments to the “Sammlung alter Musikinstrumente bei der Königlichen akademischen Hochschule für Musik”, which is now the Musikinstrumenten-Museum PK, Berlin. Among them were 13 recorders, three of them still exist and two are still in a limited playable condition. These recorders, signed “HD” (Kat.-Nr.:659 & 660), have some special features, which draw interest in their acoustical qualities: they appear to be built as a pair of recorders. One labium is placed on the back side and both instruments have different bore profiles. It seems that one recorder was designed as the leading and the other as the accompanying instrument. Therefore it was decided to produce a high quality recording with musicians, who had ample experience with historic instruments and a solid reputation for performing contemporary music. The recorders were examined and over a period of several weeks meticulously prepared to avoid any damage as far as possible. These recordings were combined with a concert to make the best use of this singular event. In 1999 a selection of recordings were published together with similar records of other Naumburg instruments and now the second edition of this CD is on sale since 2014.

Figure 4: CD-Cover and Recorder Kat.-Nr.: 659 & 660 © Musikinstrumenten-Museum PK, Berlin

3.4. Conserving the Recordings

Of course there are not only audio recordings made to be sold on CD. In fact, documenting sound with various media is pretty old. So we have to handle and preserve various formats. The conservation of data media is relatively young and has grown to an own specialised field in the science of conservation.

Even during the production of the above mentioned CD Die Blasinstrumente aus der St. Wenzelskirche in Naumburg, which took place during a period of about ten years, multiple media formats got used. Over the decades, starting in 1930, the following media were in use and are to be stored in our institute:

recorded disc
- shellac
- vinyl

magnetic tapes (analogous)
- from ¼’’ to 2’’

magnetic tapes (digital):
- U-matic
- Betamax

optical discs
- CD


Not only need these different media to be stored and preserved. But we also require the reproducing devices which have to be kept in working condition. Due to the fact that audio recording got dominated by powerful data processing during the last decades, we additionally have to care for the appropriate IT Hardware and the associated software.


(1) The Mighty Wurlitzer – Highlights of Movie Theater Music. Played by Robert Ducksch. Berlin 1991

(2) Das "Bach-Cembalo" im Nachbau : Christine Schornsheim, Cembalo, Berlin, 1998

(3) Dieter Krickeberg & Thomas Lerch: Die Blasinstrumente aus der St. Wenzelskirche in Naumburg – Eine Einführung in Wort und Ton, Berlin 2011

(4) Thomas Lerch: Der Klang historischer Blockflöten. Ein Berechnungsverfahren zur Klangvorhersage. In: Günther Wagner (Hrsg.): Jahrbuch des Staatlichen Instituts für Musikforschung Preußischer Kulturbesitz 1997, 146 - 68, Stuttgart 1997

A zither resonance-table with an integrated tuning-button

Heidi von Rüden
Musikinstrumenten-Museum, Staatliches Institut für Musikforschung Berlin, Germany

Extended Abstract


If we inspect old and broken musical instruments for a restoration we get lots of documentation material which helps to choose the right direction, how to work with the object and how to conserve it. For the usual visitor it might be interesting to take these single elements and disaggregate contexts. At the end of the process we get a replica, different concepts for a repair or an object in a restored condition.


Inside the german zither of Friedrich Idinger, Berlin 1892 (Kat.- Nr. 4382) and the zither resonance-table of Eduard Bock, 1874 (Kat.- Nr. 5563) a small sound-producing-system is integrated. The devices are not visible from the outside. Gravures with the letter “A” on the metal cover and a button refer to the sound for tuning. The principles of sound production are different when released at the touch of the button. At the zither of Idinger a small lever plucks a reed of metal. At the zither resonance table parts of the hammer-mechanism are missing. Different methods help us to decode the meaning and effectiveness of these objects.

Fig 1: Zither, Friedrich Idinger, Kat.- Nr. 4382 Foto: Irmgard Otto, Berlin 1960


The tuning is always in focus of literature about instruments. Kennedy wrote about the Konzertzither: „Die Konzertzither ist, weil mensurlänger als die Primzither, von vollerem, kräftigerem Tone. Da sie aber trotzdem nicht tiefer gestimmt sein darf, **) ist sie saitenstraffer als jene und bedingt kräftigere Hände.“ ( **) Vielfach wird sie allerdings in (as) ̅ gehalten.)“ (1)

The zither of Friedrich Idinger has a long scale-length, like the one Kennedy described. The instrument is not in a playable condition. Most strings are fastened on the tuning pins though under very low tension. Some strings broke at the bridge, others broke close to the nut at the winding and part from the core made of silk. The bridge separated from the soundboard. Shrinkage and deformation are found quite often on plucked instruments. Apart from the fatigue of material all these damages indicate to a wrong stringing.

Kennedy described in the year 1896 different zither types with several sizes and tunings. The tension of the string is very important for the development of an instrument. A wrong stringing can cause damages. Hundred years ago it was not common to have a discerning choice of replacement strings, for long or short string length. What Kennedy means with tight strings and strong hands we can show evocative to the visitor of a museum. Just 20mm difference of the scaling would increase the tensile force of one string by 11 Newton.

There are different parameters which allow a reconstruction of the tensile forces from the blank fretboard-strings. The small metal reed is in a sounding condition and refers to the note pitch for tuning. It produces a frequency of 431,8 Hz. An example of the sound one can find online on the website vimeo.com (cue: Zither, Friedrich Idinger). The diameter and material are also important for the calculation. With a formula developed by Brook Taylor in 1708 the string tension can be calculated. (2)

Fig. 2: Table with different parameters of a string, Heidi von Rüden 2017

The table shows how the alterations of single parameters affect the tensile force. The museum keeps five little reels with blank strings for zither on stock. These parts are from the time when the zither of Idinger was in use. The diameters of these replacement-strings are smaller, the a1-string from iron is just 0,35mm strong. The graphic shows the difference from 0,01mm in the diameter which changes the tensile force to 5 Newton which correlates to about 0,5kg. It is not easy to imagine that the influence is that strong. A one-dimensional string is a good example to explain a visitor the connection between the physics and acoustics. To engage the interest practical experiments with weights are a good opportunity.

Fig. 3: Diagram with different iron string diameter and its tension, Heidi von Rüden 2017

Zither-resonance table

Nowadays a musician needs his own table where to put and play the zither. Damaged table-surfaces caused by playing an instrument in public houses are no longer incurred by the barkeepers. For the last hundred years the playing position of the zither did not change remarkably. The center line of the fingerboard lies nearly in an angle of 35 degrees to the front of the player. The peaks of the little feet are pressed into the table top and stabilize the position of the instrument. The modern zither combines the principle of the stringing in a line and the contrary dividing the string on a fretboard. Therefore the right and the left hand operate in a very different way. The right hand is actually the sound producing element. (3)

The resonating body of the zither encloses a quiet small air volume because the sides have a very low level. This is a disadvantage for the deep sound of the low strings because the vibrations have no place to develop. Examinations show contrasts in radiations by the use of different playing-tables. A zither-table is relevant for the sonority and character of the sound. (3, 4, 5) Already at the beginning of the 20th century many inventions with patent specifications were made to improve the sound of the very popular instrument.

The undamped and covibrating strings of the stringed keyboard instruments are part of the sound producing system for many hundred years. The sound of the zither gets a special character because of the sympathetic strings. The aliquodium is a development of this principle. It is like a substructure underneath the zither which amplifies the sound by resonating strings, made in the 1890s in a transportable size.

Fig. 4: Zither resonance-table, Kat.- Nr. 5563, Foto: Sophie Kleinbeck, Berlin 2016,
Fig. 5: Zither resonance-table, Kat.- Nr. 5563, X-ray: Christoph Schmidt, SMB, Berlin 2016

The zither resonance-table with its integrated tuning-button consists of two parts. The actual resonance box is buildt in a table rack. Fit in the ribs the box just fastened by small wooden strips and a few screws. For studies with the endoscope, for acoustic measurements, the record of an x-ray picture and other reasons this part was separated from the table frame. (6, 7) The speciality of the resonating soundbox is the chromatic stringing. On the bottom side there are 40 sympathetic strings. They range from Contra octave C1 to d and complete together the already existing strings of a zither. The notation is marked near the tuning pins. The last string with some space to the neighbor is the a-string. Through a hole in the soundboard it was possible to tap this single string by the hidden mechanism inside the box. Unfortunately this part is not complete any more but the movement is still working when activating the button on top. A video with the endoscope one can find online at vimeo.com (cue: Zitherresonanztisch). Probably there was a solid sound generator integrated, like the small reed in the Idinger zither, which gave orientation for tuning.

The strings are no longer in tune. A metal frame and metal braces hold the huge tensile force of the strings which has an effect on the whole sound body. The tension is about 80 Newton for a 1mm diameter iron string, or 3200 Newton at all.
For a trial of the acoustic a playable zither, the resonance box of the zither table and both objects together were measured in an anechoic room. A sinus sweep signal was given to the objects and the reaction was recorded by microphones. The graphic of a spectrograph shows the sonority of the only zither and the improvement while putting the zither on the resonance box. A rehearsal confirmed this effect.

Fig. 7: Schlesinger, Anton: Spektrogramm einer Zither und einer Zither auf dem Resonanzkasten, Kat.-Nr. 5563 aufliegend (Akustische Vermessung am SIM) Berlin 2016

The zither table from Eduard Bock was probably made for private setting. The soundboard has three little knobs turned from hardwood. Their position fit to the outline and small feets of a small instrument lying on top. To improve the transmission of the sound there is a soundpost located directly underneath one of the knobs.


With present-days methods it is impossible to incorporate visitors of a museum to musical instruments. Every part of a zither has its special task and the applied function of a resonance table can engage the visitor interest. These two zither objects have many capabilities to copy and learn from.


(1) Kennedy, Hans: Die Zither in der Vergangenheit, Gegenwart und Zukunft, Tölz 1896, S. 114
(2) FZ(N) = 3140 ρ(g/cm³) L²(m)² f²(kHz)² d²(mm)²
(3) Vanneste, Miriam: Untersuchungen zum Abstrahlverhalten der Zither auf verschiedenen Spieltischen [Diplomarbeit im Studiengang Ton- und Bildtechnik an der Fachhochschule Düsseldorf">, Düsseldorf 1995
(4) Meinel, Eberhard: Experimente an einer Zither, Instrumentenbauzeitschrift 1-2/1999, S. 62-67
(5) Ziegenhals, Gunter: Neuartiger Zithertisch aus dem Vogtland. In: Saitenspiel 6/2003, S. 347-351
(6) Kleinbeck, Sophie: Dokumentation eines Zithertisches aus dem Besitz des Musikinstrumentenmuseums Berlin, Kat.- Nr. 5563 (Praktikumsbericht der Fachhochschule Potsdam, Studienrichtung Konservierung und Restaurierung von Holzobjekten) Berlin 2016