Reconstruction of - people.Virginia.EDUpeople.virginia.edu/~lz2n/mse305/PipeOrgans-MRS07.pdf ·...

IntroductionThe first organ - like instrument was

built around 246 B.C. by a Greek craftsmanin Alexandria named Ktesibios. The oldeststill - playable organ in the world, built inabout 1435, is in Sion, Switzerland. In the17th and 18th centuries, the art of organbuilding reached its peak. During theBaroque Age (�1600– 1750), the concept oforgan building was governed by the ideaof replicating the orchestral sound. For theProtestant church, the organ was a centralcomponent of the church service. As a re-sult, the rich and strongly Protestant regionsof northern Germany and the Netherlandsbecame primary centers for organ buildingduring the Baroque era.

The industrial revolution, the influenceof romantic and modern music styles, andan increasingly avid audience radicallychanged the aesthetic concept, design, andmethods of organ building in the 19thand 20th centuries. Organs were now con-structed in large factories by many workersand machines, in contrast to the previoussmall workshops with only a few artisansand an organ master. More expressive ranksand a crescendo pedal, along with moderntechnical innovations (e.g., electrifi cationof the mechanical parts), new ma te rials,and the demand for colossal orchestral or-gans, drastically changed the organ sound.As a result, the profound knowledge of

Baroque organ building, which had beenpassed down and improved over genera-tions, was lost.1–3

Recapturing a Lost ArtThe second half of the 20th century saw

a revival of interest in Baroque music, andthe realization that a historically accuratesound could only be achieved by using ad -equately restored Baroque period instru-ments or new ones built using traditionaltechniques. Therefore, interest has grownin recapturing the lost art of organ build-ing in order to restore and build new or-gans with the appropriate sound qualities.

During the last 10 years, the GöteborgOrgan Art Center (GOArt), in close collab-oration with researchers at Chalmers Uni-versity of Technology, both in Göteborg(Gothenburg), Sweden, has developed newtechniques for manufacturing organs withBaroque sound based on scientific research.4,5

As a result, they have succeeded in bothaccurately restoring historical Baroque in-struments and producing new organs withtrue Baroque sound, within the frame workof the Swedish - and European - fundedNorth German Organ Project.

The first of such organs—inspired bythe Arp Schnitger organs built in theLübeck Cathedral (1699, destroyed 1942)in Lübeck and the St. Jakobi Church (1693) inHamburg, both cities in northern Germany—was constructed in the research workshopof GOArt and installed recently in theÖrgryte Nya Kyrka in Gothenburg (Fig-ure 1). Other new organs with true Baroquesound have been recently inaugurated inthe Noorderkerk, a church in Rijssen, theNetherlands (built by the workshop ofHenk van Eeken, who par ticipated in theNorth German Organ Project), and at theKorean National University of Arts in Seoul.A copy of the largest and best - preservedlate Baroque organ in northern Europe,built by Adam Gottlob Casparini in 1776for the Church of the Holy Spirit in Vilnius,Lithuania, and suitable for the music ofJ.S. Bach, is currently under constructionat the University of Rochester’s EastmanSchool of Music and will be inauguratedin Christ Church, Rochester, in 2008.

The demand for such Baroque - era in-struments—restored originals or new re-productions—is continuously growing. Inthe framework of a European projectcalled TRUESOUND, four research insti-tutes and five organ builders worked to-gether on the reconstruction of historicalcopper alloys—namely, brass—which dif-fer in composition, microstructure, me-chanical properties, and workability fromcurrently commercial available ones. As aresult of this project, organ builders receivednewly fabricated organ parts made from

MRS BULLETIN • VOLUME 32 • MARCH 2007 • www.mrs.org/bulletin 249

Reconstruction ofHistorical Alloys forPipe Organs BringsTrue Baroque MusicBack to Life

B. Baretzky, M. Friesel, and B. Straumal

AbstractThe pipe organ is the king of musical instruments. No other instrument can compare

with the pipe organ in power, timbre, dynamic range, tonal complexity, and sheer majestyof sound. The art of organ building reached its peak in the Baroque Age (�1600–1750);with the industrial revolution in the 19th century, organ building shifted from a traditionalartisans’ work to factory production, changing the aesthetic concept and design of theorgan so that the profound knowledge of the organ masters passed down overgenerations was lost.

This knowledge is being recreated via close collaborations between researchscientists, musicians, and organ builders throughout Europe. Dozens of metallic samplestaken from 17th - to 19th - century organ pipes have been investigated to determine theircomposition, microstructure, properties, and manufacturing proc esses using sophis -ticated methods of ma te rials science. Based upon these data, technologies for casting,forming, hammering, rolling, filing, and annealing selected lead - tin pipe alloys and brasscomponents for reed pipes have been reinvented and customized to reproduce thosefrom characteristic time periods and specific European regions. The new ma te rials recre -ated in this way are currently being proc essed and used by organ builders for the restora -tion of period organs and the manufacture of new organs with true Baroque sound.

and

these alloys, tested them, and installed theparts in Baroque church organs, includingthe 1718 organ in the Magnuskerk in Anloo,the Netherlands (Figure 2); the 1701 instru -ment in the Evangelic Lutheran Churchin Ugale, Latvia; and the newly built VoxHumana stop for the famous Caspariniorgan (1776) in Vilnius.

The Baroque Pipe Organ:Construction and Operation

The pipe organ is a musical instrumentin which the sound is produced by forc- ing air, or “wind,” at a constant pressurethrough numerous pipes. The organistchooses the sounding pipes by pulling theregister knobs and pressing keys either man -ually or using a pedal keyboard. While allorgans have flue pipes (Figure 3), more so-phisticated organs also contain reed pipes(Figure 4).

Flue pipe construction is reminiscent ofa recorder: the flue pipes are usually open atthe top and tapered at the bottom, with a

“mouth” running across the flattened sec-tion above the tapered part. Inside the pipeis a “languid,” or tongue (a fixed horizontalplate), with a “flue” (a narrow slit) betweenit and the lower “lip” of the mouth. Thewind, supplied by large bellows, entersthe pipe at the tapered foot and causes thepipe to vibrate. When the wind is admit-ted to the flue pipe by the actuation of theappropriate stop and key, it flows upwardand forms a sheet - like jet as it emergesfrom the flue slit. The jet flows across themouth and strikes the upper lip, where itinteracts with the upper lip and the lan-guid, thus inducing the column of air in thebody of the pipe to vibrate and to maintainthe steady oscillation that generates thepipe’s “speech.”

Reed pipes, which imitate the trumpetsand trombones of an orchestra, add beau-tiful warmth or a blazing fanfare to thetonal composition of the organ. The soundproduction in reed pipes is similar to thatin reed instruments. When wind enters

the bottom of the reed pipe, a small metaltongue vibrates against the shallot, pro-ducing sound, which is am plified andmodified by the resonator (Fig ure 4a). Thesound of the reed pipes crucially dependson the tongue curvature adjusted by theorgan builder during voicing. The pitch ofthe reed pipe is adjusted by moving theposition of a tuning wire up or down. Thisholds the tongue against the shallot, andthus lengthens or shortens the part ofthe tongue allowed to vibrate. Several pa-rameters determine the organ’s char -acteristic sound and timbre: the shape ofthe resonator, the metal used for thetongue, the wind pressure, and the pipedimensions. Without reed pipes, much ofthe great organ music cannot be per-formed successfully.

Materials Scientists and OrganBuilders: A Research Collaboration

Since the appropriate ma te rials for ade-quate reconstruction and restoration of

250 MRS BULLETIN • VOLUME 32 • MARCH 2007 • www.mrs.org/bulletin

Reconstruction of Historical Alloys for Pipe Organs Brings True Baroque Music Back to Life

Figure 1. New Baroque-style organ constructed using Baroque technology and installed in 1999 in the Örgryte Nya Kyrka in Gothenburg, Sweden.

Baroque - era organs are either not com-mercially available or their composition,microstructure, mechanical properties, andworkability are not known, several researchprojects were undertaken to investigateand reconstruct the original techniques forproducing and proc essing alloys for organpipes and brass for reed pipe tongues. Amain goal was to improve both the soundquality and the brass workability, which isespecially important for reed tongues. TheTRUESOUND project, funded by the Eu-ropean Union, enabled direct cooperationbetween ma te rials scientists and organbuilders. As a result, the organ builders re-ceived new copper alloys, tested them,and used these new ma te rials to both restore old organs and build new oneswith historical sound. This ar ticle containsa brief description of the results of theseinvestigations.

Alloys for Flue Pipes and Reed Pipe Resonators

Studies of historical organ pipes showedthat lead - tin pipes were often sand - cast.5Unfortunately, detailed descriptions of the

sand - casting methods of 17th - century organbuilders no longer exist.

Within the framework of the North Ger-man Organ Project, the casting proc ess fororgan pipe ma te rial was reinvented.1,2,4 – 6

Tin and lead are melted in a pot. At a cer-tain temperature, depending on the melt-ing temperature of the alloy and the size ofthe pipe to be cast, the molten metal ispoured into a casting box. The worker thenquickly moves the casting box at a con-stant speed lengthwise down the sandbench, leaving a thin metal sheet behind.Due to the casting technique with a mov-ing casting box, the cast sheet thins outcontinuously in the direction of movementtoward the end. The metal solidifies immediately on the thick sand bed, whichis a high - heat capacity mixture of sand andfluid (e.g., olive oil). The metal sheet coolsdown rapidly to the temperature of thesand bed and then cools down furthervery slowly. The pipe ma te rial producedin such a way possesses enhanced ma te -rials properties in terms of hardness, stability, workability, and sound quality,compared with commercially available pipe

sheets. Historical organ pipes are alsooften thinner at the top, which gives thembetter stability and simultaneously bettersound resonance. The proportion of impu-rities or trace elements in the metal, thecasting temperature, and the type and tem -perature of the sand–fluid mixture usedfurther influence the metal properties andconsequently the sound quality.1,2,6

Alloys for Tongues and ShallotsReed pipes (Figure 4) are constructed in

a different manner than flue pipes. Theircentral part consists of a tongue and a brassshallot. The resonator is normally made ofa lead - tin alloy, as in flue pipes. The tonguevibration crucially determines the reed pipesound. The vibration behavior depends onthe elastic properties of the brass sheet andtherefore mainly on the brass composition,microstructure, and proc essing. The organbuilder first receives the brass after cast-ing, mechanical treatment (hammeringand/or rolling), and annealing. Then thebuilder cuts and thins the sheet intotongues with the appropriate size and thick -ness and finally files and slightly bendsthe brass tongue to induce the appropriatecurvature for creating the best sound. Theworkability of the ma te rial is a very impor -tant issue during the voicing of the pipeand is determined by the desired responseof the brass to specific treatments made bythe organ builder that simplify the workand improve the quality.

In order to meet the organ builders’ re-quirements, the scientific partners investi-gated the ma te rial composition and thesequence of the heat treatments and me-chanical forming proc esses. The workabil-ity and acoustic properties of historicaland reconstructed alloys were evaluatedby the organ builders.

CompositionThe composition of period tongues and

shallots was nondestructively meas ured onabout 30 samples borrowed from organsproduced between 1624 and 1880 in vari-ous European countries (Belgium, France,Germany, the Netherlands, Italy, Latvia,Lithuania, Sweden, and the United King-dom). The need to conserve the periodinstruments posed severe limitations onthe sam ple size and surface treatment of themetals available for testing. For all samples, the concentrations of the maincomponents (Cu, Zn, Pb) were meas urednondestructively by means of neutron dif-fraction (ND) and x-ray diffraction (XRD),using the tongues and shallots as received.Since such analyses included the contami-nated surface layer, the results were controlled by applying electron probe mi-croanalysis (EPMA) to tiny 1–2 mm2



Figure 2. Period Baroque organ (1719) in the Magnuskerk in Anloo, the Netherlands, restoredin 1999 using Baroque technology.

surface - cleaned triangular samples, cut offfrom only a few tongues at the edge of thenon - vibrating parts (close to the block,behind the tuning wire). Secondary - ionmass spectroscopy (SIMS) was used toidentify trace elements in the samples notdetectable by ND, XRD, and EPMA, andinductively coupled plasma optical emis-sion spectroscopy was used for chemical

analysis. This integral method allowed usto additionally verify the data obtained bylocal SIMS and EPMA analysis on the con-centration of lead, which is distributednon - uniformly in the brass. In order toobserve the microstructure of the brassma te rial, light and scanning electron mi-croscopies were performed on some shorttongues, which were carefully polished on

a small area of the non - vibrating part.Only a few damaged samples (such asthose from the organ in the EvangelicLutheran Church in Ugale, Latvia) couldbe used and cut into small parts of 3 - mmdiameter to study by means of transmis-sion electron micros copy.

The main components of tongues andshallots are copper, zinc, and lead. Zinc issoluble in copper, whereas lead is insol -uble. The total concentration of other elements—for ex ample, iron, manganese,nickel, and tin—was surprisingly low:�1 wt% for samples from the 17th centuryand �0.3–0.5 wt% for samples from the19th century. Since the impurity concen-trations are below their solubility limit inCu, the impurities are all expected to be insolid solution. Therefore, they influencethe brass properties in a similar way as Znand were not considered for the develop-ment and manufacturing of new alloys.

In all samples, the Zn concentration wassurprisingly constant over time (Fig-ure 5a).7 Between 1624 and 1790, it was�26 wt%. A higher zinc concentration of�32.5 wt% additionally appears around1750. These two concentrations coexistedfor 40 years. From the end of the 18th cen-tury up to the present day, the Zn concen-tration has remained at the higher level of32.5 wt%. According to the Cu–Zn phasediagram, all historical tongues and shallotswere made of α - brass, which contains onlyone copper - rich phase, namely, the fcc αsolid solution of Zn in Cu (Figure 6).Since the Zn concentration does not ex-ceed the solubility limit in Cu, the nextphase in the Cu–Zn phase diagram—the



Figure 3. (a) Schematic illustration of a Baroque organ flue pipe. Dotted line shows airflowpath. (b) Period flue pipes from the Casparini organ (1776) in the Church of the Holy Spirit inVilnius, Lithuania.

Figure 4. (a) Schematic illustration of a reed pipe. (b) Components of a reed pipe (without resonator and boot), including the tongue and shallot,from the Arp Schnitger organ (1680) from the former St. Johannis monastery church in Hamburg, Germany. This organ was moved in 1816 toSt. Peter and Paul Church in Cappeln, Germany. (c) Reconstructed Vox Humana reed pipe stop from the Casparini organ (1776) in the Churchof the Holy Spirit in Vilnius, Lithuania.



β - phase—does not appear in historicaltongues and shallots. The tongues andshal lots always contained lead before1750. The concentration of lead slowly de-creased from 7–8 wt% in 1624 to 2 wt%by the middle of the 18th century. The firstlead - free tongues ap peared around 1750.After 1820, lead completely disappearedfrom the studied brass.

Why is the zinc concentration at a lowerconstant level before 1790? Why does it in-crease later and remain at the level of 32.5wt%? Before 1738, Zn was only availableas zinc oxide or zinc carbonate(“calamine”), and not as pure metal.8,9

Therefore, brass could not be produced bymelting together the pure metal compo-nents, as could be done for alloyingcopper and tin into bronze. If one tries toreduce zinc ore by char coal in an open fur-nace, the zinc immediately evaporates andoxidizes.

Brass was produced by a proc ess calledcementation: pieces of copper, coal, andcalamine were put together into a pot,heated to a certain temperature above theboiling point of zinc (907�C) but belowthe melting point of Cu (1083�C), and an-nealed for several hours. The calaminewas thus reduced, and the evaporated Zn

immediately diffused from the gas phaseinto the hot but solid copper. Below 907�C,the proc ess is not possible; on the otherhand, heating much above 907�C was noteconomi cal, since it required too muchcoal. Therefore, the cementation was per-formed within a rather narrow tempera-ture range. The experienced human eyecan estimate temper ature from the color ofa furnace to within 20–30�C. The Zn con-centration in brass is determined bysolidus concentration (max imum solubil-ity of Zn in solid Cu), which is exactly 26wt% Zn at approximately 920�C (Fig-ure 6).10 Thus, the cementation proc ess ingtemperature for pe riod brass was probablyaround 920�C. This method of makingbrass was carried out with slight variationsthroughout the 19th century, and as late as1858, calamine furnaces were still working(for ex ample, in South Wales).11

William Champion took out a Britishpatent in 1738 for distilling metallic zincfrom calamine by reduction with charcoalor coal.9 In 1781, the first patent for alloyingbrass with metallic Zn appeared in Eng-land. After Zn became available as a puremetal, the maximum concentration of Zn inCu was no longer limited by the solubilityat 920�C (i.e., above the boiling tempera-ture of Zn), but by the maximum solubil-ity after crystallization of the Cu–Zn melt,which is 32.5 wt% Zn.10 It is astonishinghow rapidly Zn concentration in brasschanged from 26 wt% to 32.5 wt% through -out Europe.

Let us compare the composition oforgan brass with concentrations of tin and

lead in bronze cannons (Figure 5b, meas -ured by H. Forshell8). Bronze cannons weremanufactured during the same time pe-riod and in the same European areas asorgan brass. However, bronze was alwaysproduced by the direct smelting togetherof copper and tin and not by cementation.Therefore, the tin content in bronze variedin a broad way, as depicted in Figure 5b.The points for tin content are scattered anddo not group along a horizontal line likethose for Zn in brass (Figure 5a).

Additionally, Figure 5 allows us to an-swer a second important question: was leadintentionally added to brass for tongues,or was it just an impurity? Lead is not sol-uble in copper, and it embrittles the brass.After only small deformations, the lead - containing brass must be annealed to relaxthe internal stresses, otherwise this cancause cracking and ma te rial failure. Com-paring Figures 5a and 5b reveals that thelead concentration in brass and bronze be-haves similarly over time. Between 1600and 1750, the mean Pb concentration in his -torical brass and bronze slowly decreasesfrom 7 wt% to 2 wt%, and then, around1750, it plummets to almost zero. Accord-ing to historical sources, the purification ofcopper in the 17th century through to thebeginning of the 18th century was a rathersimple and limited proc ess. Copper refiningfactories were placed in the neigh borhoodof the copper mines, such as Swansea inBritain, Falun in Sweden, and Goslar in Ger -many. Various impurities remaining in com -mercially available copper can be seen as“fingerprints” indicating the origin of the

Figure 5. (a) Zn and Pb concentration inperiod tongue and shallot brass from his -torical organ reed pipes, compared with(b) Sn and Pb concentration in periodcannon bronze.8

Figure 6. Cu–Zn phase diagram showing the concentration range for brass produced be-fore 1790 and after 1750. Between 1750 and 1790, the two concentration ranges coexisted.

copper ores. Indeed, chemical analysisshows that impurities in cop per obtainedfrom different mines vary widely.8,12 Ofcourse, the exact composition was unknownto the organ builders buying copper on themarketplace or from a coppersmith in theBaroque era. However, they knew the dif-ferences in properties among copper prod -ucts from different mines, and which copperwas more suitable for which application.

At the end of the 18th century, copperproduction exploded and copper refiningfactories became very large. They evenmoved from the neighboring copper minesto harbors. Copper ores were deliveredfrom different mines and even importedfrom overseas.9 This mixing of ores resultedin the production of copper with similarproperties irrespective of the mine fromwhich the raw ma te rial came. A rather com -plex multistage refining proc ess was in-vented, resulting in the elimination of mostof the impurities such as tin, iron, and lead.12

The earlier, one - stage refining proc esswas simply not able to remove all the leadfrom the copper, although the refining ofcopper from lead and silver was a goal ofcraftsmen even in the 16th century, as evi-denced by Georgius Agricola’s (1494–1555)description of contemporary metallurgicaltechnologies in his encyclopedic De remetallica libri XII.13 Organ brass and can-non bronze are completely different prod-ucts. However, lead concentration levelsdisplay a similar pattern both in organ brassand cannon bronze, as shown in Figure 5.Therefore, it is rather improbable that leadwas added intentionally to the organ brassby craftsmen or organ builders. An addi-tional source of lead can also have been theZn ore, which always contains some lead.14

Mechanical and Heat Treatment of Brass

According to Dom Bedos, writing in 1766,organ builders did not produce the brassma te rial themselves (in contrast to thelead - tin alloys for pipes),15 since it was toocomplicated and required special high - temperature equipment. Organ buildersprobably purchased their brass directlyfrom coppersmiths in sheets or bands. His -torical sources tell us that melted brass wascast into molds or “poured between twostones of a ton weight or more, each ofwhich was elevated at one end. The moldswere placed in an upright position, and themetal was allowed to cool, producing aplate of about 70 lb. weight.”9 Experimentsshowed that the minimum sheet thicknessthat could be obtained by this method is�3–4 mm. Dom Bedos does not tell usabout the thickness of the brass strips pur-chased by the organ builders. However,the final thickness needed for the brass

tongues is �0.2–0.5 mm, depending on thepitch. The thickness of the shallot walls is�1–2 mm. In order to get the appropriatethickness for the tongues and shallots, respectively, the brass sheets had to bethinned further.

According to historical sources, the castbrass blocks were hammered either bycoppersmiths in battery mills or manuallyby the organ builders.8,9,11,13,14 Toward theend of the 17th century, rolling in additionto hammering came to be used (at least inBritain) for flattening brass and copper in-gots.9 These were huge rolling mills, pow-ered first by water and later by steam, butthey were not economical for small organmanufacturers. Therefore, the organ buildersprobably obtained brass sheets 2–4 mm thickand thinned them further by hammering.15

However, if one tries to hammer brasscontaining 1–2 wt% Pb from 2 mm downto 0.5 mm, the brass easily breaks. In orderto prevent failure, several intermediate an -neals had to be performed. Microstructuralinvestigations revealed that historicaltongues contain well - annealed and recrys-tallized grains with numerous twins, typi-cal of all copper alloys (Figure 7).17,18 Themean grain size is rather constant in sam-ples from the same organ, but varies enor-mously, from 10 μm to 200 μm, in samplesfrom different organs (Figures 7a and 7b).X - ray diffraction meas ure ments did not re -veal a rolling texture. These results almostexclude rolling as a technology for mechan -ically treating organ tongues; they weremost likely cast and hammered (with in-termediate anneals). Numerous twin bound -aries, always present in Cu - based solidsolutions, allowed us to estimate roughlythe temperature of the intermediate an-neals of historical brass. The twin bound-aries in copper and copper - based alloysmay contain crystallographically differentfacets.16–18 At high temperatures close tothe melting point, only two facets are pres-ent in twin boundaries, namely, the sym-metric twin boundary and the so - called 9Rfacet.16–18 If the an nealing temperature de-creases, new crystallographically differentfacets gradually appear.

The temperatures for the appearance ofdifferent facets were meas ured experimen-tally. The spectrum of facets observed in his-torical brass tongues was compared withthe spectrum of facets observed in themodel alloys.17,18 The estimated tempera-ture of intermediate anneals is �600�C.

At the last stage, tongues were carefullyfiled from both sides and slightly rolledfrom one (upper) side in order to get asmall curvature. This is needed to let theair inside the reed pipe through the gapbetween tongue and shallot. The tonguestarts to vibrate under the action of the

wind. However, the vibration should notbe too strong, which would cause thetongue to hit the shallot.

Manufacturing New BrassMaterials for Historical Reed Pipes

Taking into account our investigationsdescribed here, two new alloys were pre-pared in order to reproduce brass from the17th and 18th centuries (25 wt% Zn and2 wt% Pb) and from the 19th century(30 wt% Zn, Pb - free). The 10 - mm - thickcast ingots of Pb - free alloy were ham-mered with 2–4 intermediate anneals at600�C. The alloy containing lead was ham-mered or carefully rolled from the 3 - mmcast sheet with 6–8 intermediate anneals at600�C. Five organ builders performed thefinal treatment and voicing of historicalreed pipes with original and reconstructedtongues. They judged the workability ofnew alloys as being very close to thatof historical tongues.

Good workability is essential for thefinal treatment and voicing proc ess of thebrass tongue. The final proc ess is extremelydelicate: the organ builder must ensurethat the tongue has the right thickness,form, and curvature, which must remainstable and durable. These parameters



Figure 7. Light micros copy images ofbrass tongues from (a) the AntoniusWilde organ (1598–1599), restored byArp Schnitger (1682) in the St. JakobiChurch, Lüdingworth, Germany; and(b) the Radeker & Garrels organ (1719)in Magnuskerk, Anloo, the Netherlands.

scientific career at the MPI-MR. From 1995 to2003, Baretzky headed the Central ScientificFacility for Surface Analysis at MPI-MR. Shebecame the deputy head of her current depart-ment in 2003.

Baretzky’s research interests are surface sci-ence, interfaces in condensed matter, phasetransformations, oxidation, coatings, multi-layers, nanomaterials, and magnetic materials.

Baretzky can be reached at Max-Planck-Institut für Metallforschung, Heisenberg-strasse 3, D-70569 Stuttgart, Germany; tel.49-711-689-1890, fax 49-711-689-1892, ande-mail [email protected].

Milan Friesel is an asso-ciate professor at the SIMSLaboratory at ChalmersUniversity of Technologyin Göteborg, Sweden.

He obtained his PhD de-gree in experimental high-pressure physics fromChalmers in 1987. From

1988 to 1991, he was a guest researcher at theMax Planck Institute for Metals Research inStuttgart. Friesel joined the SIMS Laboratoryat Chalmers in 1994. His research interests aresuperionic conductors, metals and alloys,semiconductors, and characterization by theSIMS technique.

Friesel can be reached at Fysik och TekniskFysik, Fysikalisk Elektronik och Fotonik,41296 Göteborg, Sweden; tel. 46-31-7723434,fax 46-31-7722092, and e-mail [email protected].

Boris Straumal is head ofthe Laboratory for Inter-faces in Metals at theInstitute for Solid-StatePhysics of the RussianAcademy of Sciences inChernogolovka and a fullprofessor at the MoscowState Institute of Steel and

Alloys, University of Technology (MSISA).He obtained his PhD degree in materials sci-

ence from MSISA in 1983. For many years, hewas a guest researcher at the Max Planck In-stitute for Metals Research in Stuttgart.Straumal has been with the Russian Academyof Sciences and MSISA since 2003. His re-search interests include grain boundaries,phase transformations, diffusion, thermody-namics, coating technologies, crystal growth,and nanomaterials. He has authored or co-edited six monographs and textbooks, trans-lated seven scientific books into Russian, andwritten approximately 180 papers.

Straumal can be reached at Max-Planck-Institut für Metallforschung, Heisenberg-strasse 3, D-70569 Stuttgart, Germany; tel.49-711-689-3478, fax 49-711-689-1892, ande-mail [email protected].



crucially influence the tongue’s vibrationand, with that, the reed pipe sound. In thelast mechanical treatment, before makingthe curvature in the tongue, the organbuilder files down the tongue to its finalthickness using a special file. The file mustglide over the metal and not stick, in orderto prevent warping during this treatment.Warping is a serious problem because awarped tongue does not vibrate properly.The target of the last step is to create a per-manent curvature in the tongue. Accord-ing to the organ builders’ observations,modern brass ma te rials do not fulfill all ofthese qualities.

After proper treatment and voicing ofthe new tongues in the historical reedpipes, the sound created by the newtongues could not be distinguished fromthat produced by historical ones. The newalloys enabled many irreparably damagedtongues in the Lutheran church organ inUgale, Latvia, to be completely recon-structed, and the missing Vox Humanastop in the Casparini organ in the Churchof the Holy Spirit in Vilnius to be built.

ConclusionsAs a result of our investigations,1,2,4 – 7,17,18

the period sound of Baroque pipe organshas been brought back to life. Newly de-veloped alloys were applied for therestoration of historical organs and for build -ing new organs with Baroque sound.Careful investigations of historical organalloys from nine European countries wereperformed. Composition, structure, prop-erties, and proc essing parameters for his-torical brass were determined by usingsophisticated methods of ma te rials science.The breakthrough was achieved by sand - casting the appropriate pipe alloy and byfabricating reproduction brass tongues forreed pipes.

AcknowledgmentsAuthors would like to thank the organ

builders Henk van Eeken (Holland), PatricCollon (Belgium), Marco Fratti (Italy),Mats Arvidsson (Sweden), Rimantas Gucas(Lithuania), Ja–nis Kalninš (Latvia), andAlexander Schuke (Germany) for provid-ing historical tongues for our investiga-tions and for fruitful discussions. Theinspiration of artistic organ playing anddiscussions with Profs. Harald Vogel andHans Davidsson are heartily acknowl-edged. The investigations were supportedby the European Commission under CRAFTproject TRUESOUND (contract COOP - CT - 2004 - 005876) and INTAS (contract 05 - 10000008 - 8120).

References1. T. Clarke, Nature 427 (2004) p. 8.

2. M. Yokota, The Overtornea Project, edited byL.W. Ericsson (Musikhogskolan i Pitea, Pitea,Sweden, 1997).3. G.A. Audsley, The Art of Organ Building(Dover, Mineola, NY, 1965).4. J. Speerstra, ed., The North German Organ Research Project at Göteborg University (GOArt,Gothenburg, Sweden, 2002).5. A. Carlsson, H. Davidsson, P. Ruiter - Feenstra,S. Dunthorne, and J. Speerstra, Tracing the OrganMasters’ Secrets: The Vision, The Process, The Goal,The Reconstruction of the North German BaroqueOrgan for Örgryte Nya Kyrka (GOArt, Gothen-burg, Sweden, 2000).6. P. Svensson and M. Friesel, Influence of alloycomposition, mechanical treatment and casting tech-nique on loss factor and Young’s modulus of lead - tin alloys (Chalmers University of Technology,Gothenburg, Sweden, 1999).7. B. Straumal, A. Mazilkin, A. Manescu, F.Rustichelli, M. Friesel, and B. Baretzky, Wieder-aufbau der Casparini Orgel in Vilnius, edited by R.Gucas (University of Vilnius, Vilnius, Lithuania,2007).8. H. Forshell, The inception of copper mining inFalun (Akademitryck AB, Edsbruk, Sweden,1992).9. W.O. Alexander, Murex Rev. 1 (1955) p. 1.10. T.B. Massalski, ed. Binary alloy phase diagrams(ASM International, Materials Park, OH, 1993).11. J. Percy, Metallurgy: The art of extracting met-als from their ores, and adapting them to variouspurposes of manufacture (John Murray, London,1864).12. Rh. Jenkins, Trans. Bristol GloucestershireArch. Soc. 63 (1946) p. 1.13. G. Agricola, De re metallica libri XII (Froben,Basel, 1556).14. J. - G. Gallon and H.L. Duhamel du Monceau,Die Kunst Messing zu machen, es in Tafeln zugießen, auszuschmieden, und zu Drathe zu ziehen(Akademie der Wissenschaften zu Paris,Leipzig, 1766).15. Dom François Bedos de Celles, L’art du facteur d’orgues (Académie Royale des Sciences,Bordeaux, 1766).16. B.B. Straumal, S.A. Polyakov, and E.J. Mittemeijer, Acta Mater. 54 (2006) p. 167.17. B. Baretzky, M. Friesel, A. Petelin, A.Mazilkin, and B. Straumal, Def. Diff. Forum 249(2006) p. 275.18. B. Baretzky, M. Friesel, A. Petelin, A.Shotanov, and B. Straumal, Def. Diff. Forum258–260 (2006) p. 397. �

Brigitte Baretzky isdeputy head of the Depart-ment for Advanced Mag-netic Materials at the MaxPlanck Institute for MetalsResearch (MPI-MR) inStuttgart.

She obtained her PhDdegree in surface science

and plasma physics from Ludwig Maximilian University and the Max Planck Institute forPlasma Physics in Munich in 1990. From1990 to 1994, she was a co-owner of an advisory company for scientific research cen-ters and industry. In 1994, she started her

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