Dutch Organ Tour 2014 1 2 Tuesday – Oudewater. 3 De Grote of Sint-Michaëlskerk Oudewater When Oudewater was still a village there was a Romanesque chapel from 1100. In 1265 Oudewater became a city. The village church expanded into a cruciform church in Gothic style, the new parts in brick. The sharp steeple was added to the new cruciform church in 1300. Between 1400 and 1500 the cruciform church was expanded, into a so-called hall church, with the aisles as large as the nave. The pillars were added and the tufa of the old walls was used now for the new south wall. In the sixteenth century, the sacristy and the choir were added plus two chapels: the north chapel as a school room, and the Baptistery. When in 1576 the Spanish troops left Holland, the altar was demolished and the pulpit became the central place. Baptisms no longer took place in a separate chapel, but in the midst of the congregation. The Baptistry is now gone, but its outline can be seen outside on the west side. 4 Explanation: 1 Nave.; below: foundations of ancient Romanesque village church (1100) 2. See roof construction; rest of Gothic Cross Church (1250), City Church 3. Hall Church (1400); three equal beech, separated by pillars 4. North Chapel (1500). Ancient altar found; leather room. Now: vestry. 5. Around chancel end (1500) 6. Gerfkamer (12th century). Originally dressing for Priest (s) Murals Markus (right) and Matthew (left) Cabinet with supper tableware grid (lattice); view on former altar in the Southern Beech | 7. Sacristy (1500). Now: vestry 8. Font, excavated in 1850 under former baptistery, see No. 14 9. Pulpit. In recent restoration in the years 1960/68 from New Church in Dordrecht transferred 9A. Blind spot. Here is the pulpit is not visible; in the Roman Catholic Church the altar was central 10. Tower (1300). Was originally a fortification. Frieze gable roof. Loud Bells (1500) 11. Organ (1840) 12. Old carillion (1600), served until 1940. Replaced because impure sound 13. Gravestone Rudolph Snell van Rooyen (1547 - 1613), Professor at Leiden in mathematics and oriental languages, also rector there and adviser to Prince Maurice. Born in Oudewater. 14. Former Baptistry (1500), see pavement and wall. 15. Entrance 5 Main Organ The main organ (monument) was built in 1839-1840 by the company Kam & Van der Meulen (Rotterdam). In 1896 the firm of Baker & Timmenga (Leeuwarden) restored it. In 1928 JC Sanders & Son (Utrecht) renewed the 8’ Trumpet on the manual and provided a new pedal board. In 1965, Baker & Timmenga restored the wind chest and wind supply. In 1994-1995 they made a complete restoration. Hoofdwerk Prestant (disc) Bourdon Prestant Holpyp Octaaf Fluit Quint Octaaf Mixtuur Fagot Trompet Cornet (disc) Bovenwerk 16' 16' 8' 8' 4' 4' 2 2/3' 2' 3 - 4 st. 16' 8' 5 st. Holpijp Quintadeen Viola di Gamba Prestant Fluit Quintfluit Woudfluit Carillion (disc) Vox Humana Tremulant Pedaal 8 8' 8' 8' 4' 4' 3' 2' 4' - 1 3/5' 8' Mechanical action. Manual compass: C-f3. Pedal compass: C-d1. Pitch: a1 = 448 Hz. Five wedge bellows. Wind pressure: 102 mm. https://www.youtube.com/watch?v=C2MZ6x7BvzY https://www.youtube.com/watch?v=KRi87SyMaOM 6 Gedekt Prestant Gedekt Octaaf Bazuin Trompet Klaroen Koppelingen 16' 8' 8' 4' 16' 8' 2' Kopp. hfdwk-bvwk Kopp. ped.-hfdwk Kopp. ped.-bvwk Omv. man.: C - f"' Omv. ped.: C - d' Choir Organ The choir organ was built in 1862 by E. Wadsworth of Manchester for an unknown location in England and moved to the Methodist Church in St. Aubin, Jersey in 1886. In Alfred Oldknow (London) changed the disposition, making a new soundchest for the Swell Organ and a new keyboard. In 2008 the organ was restored by I. Boogaard (Rijssen) and C. Butselaar (Oudewater) and prepared in Oudewater. Great: Open Diapason Dulciana Clarabella Principal Fifteenth Swell: 8 8 8 4 2 Pedal: Violin Diapason Stopped Diapason Gamba Principal Picolo Horn Tremulant Mechanical action. Manual compass: C-g3. Pedal compass: C-f1. Wind pressure: 75 mm. https://www.youtube.com/watch?v=mKdOfrcv6VI https://www.youtube.com/watch?v=1QDqChzysr4 7 8 8 8 4 2 8 Bourdon 16 Tuesday Bodegraven 8 9 10 Manuaal(C-f3) Bovenwerk(C-f3) Pedaal (C-d1) Prestant 8' Prestant 8’ Prestant 16' Bourdon 16' Fluitdoux 8' Octaaf 8' Holpijp 8' ViooldeGambe 8' Disc. Octaaf 4' Octaaf 4' Fluit d'amour 4' Trombone 8' Quint 3' Octaaf 4' Bazuin 16' Octaaf 2' Nasard 3' Subbas 16' Roerfluit 4' Gemshoorn 2' Cornet IV Disc. Carillon II Disc. Speelhulpen Mixtuur IV-VI Dulciaan 8' Tremulant Bovenwerk Tertiaan II Koppel manuaal - bovenwerk Fagot 16' Koppel pedaal - manuaal Trompet 8' Koppel pedaal - bovenwerk New organ 2014 by Reil, Heerde, inspired by the work of van Dam of Leeuwarden, and incorporating several stops from a van Dam organ of 1824 from Poeldijk. This is a planning meeting in the Reil boardroom – familiar to those who were on the 2013 trip. The following weblink gives many details of the organ. http://orgel.gergembodegraven.nl/ The church website is at http://www.bethelkerkbodegraven.nl/ http://www.bethelkerkbodegraven.nl/modules/tinycontent/index.php?id=28 has audio recordings of the last few services including some music as well as preaching. 11 Tuesday Gouda Gereformeerde Gemeente This organ was built in 2009 by van Vulpen, inspired by the Lutheran Church in The Hague. https://www.youtube.com/watch?v=ElhrIpeQiYY&index=2&list=PL28B6A85C31C04788 https://www.youtube.com/watch?v=SnQX9dlSZ5k https://www.youtube.com/watch?v=49Htbu92PWQ 12 Hoofdwerk Rugwerk Pedaal Prestant 16’ Prestant 8’ Prestant 16’ Octaaf 8’ discant dubbel Holpijp 8’ Bourdon 16’ Roerfluit 8’ Quintadeen 8’ Octaaf 8’ Viola di Gamba 8’ Octaaf 4’ Gedekt 8’ Octaaf 4’ Fluit 4’ Octaaf 4’ Quint 3’ Nasard 3’ Bazuin 16’ Octaaf 2’ Octaaf 2’ Trompet 8’ Cornet lV 4’ af c’ Gemshoorn 2’ Trompet 4’ Mixtuur lV – V Sesquialter ll Fagot 16’ Mixtuur lll Trompet 8’ Dulciaan 8’ Tremulant Manuaalomvang: C t/m e ’’’ Pedaalomvang : C t/m d ’ Stemming gelijkzwevend; toonhoogte a'=440Hz Koppels: Hoofdwerk - Rugwerk Pedaal - Hoofdwerk Pedaal - Rugwerk 13 Wednesday - Wijk bij Duurstede 14 The Grote Kerk, dedicated to St. John the Baptist, dates from 1365, however, the completion of the church took several more centuries. In 1486, work was started on the tower. The plan was to build a copy of the tower of Utrecht's Dom cathedral and make it even higher but the project was never finished and the tower only reached half the intended hight due to lack of money. As a result, it is only one of a few church towers in the Netherlands with a flat roof because the bishop couldn't afford to build a spire. Inside the tower, a picture displays the planned construction of the tower. In 1579, fire destroyed the choir but it was decided not to rebuild it, just wall up the opening. After the church's transition, in 1581, from Roman Catholic to Protestant control this wall was decorated with the "Tien Leef-regels", ("Ten Commandments"). 15 Some experts believe that Kiespenning, in constructing this organ, may have used parts of an earlier organ, possibly built by Peter Jans de Swart. In 1717, Matthias Verhofstadt rebuilt the organ, changing the Borstwerk, installing a new windchest for the Hoofdwerk and changing the disposition, using existing pipes. In 1819, Johan Caspar Friedrichs did major work, removing the Borstwerk and building a new Rugpositief, using existing pipes. In the following century more changes took place. In 1980, Gebr. Van Vulpen was responsible for a major restauration and reconstruction project, returning the organ to the 1717 disposition. A new independent pedal was added. 16 HOOFDWERK BORSTWERK PEDAAL Tremulant op hoofdwerk en borstwerk (C-c''') (CDEFGA-c''') (C-d') Koppel pedaal - hoofdwerk Prestant 8' Holpijp 8' Bourdon 16' Roerfluit 8' Roerfluit 4' Octaaf 8' Octaaf 4' Prestant 4' Trompet 8' Fluit 4' Octaaf 2' Quint 3' Flageolet 1' Octaaf 2' Regaal 8' Mixtuur 1' IV Cornet IV Sesquialter II Trompet 8' Koorgel. Keyboard compass C t/m c''' Prestant 4' Holpijp 8' Fluit 4' Octaaf 2' Pulldown pedal C t/m e The koororgan of Wijk bij Duurstede is the former rugpositief from the main organ from Friedrichs (1819), adapted by Van Vulpen in 1976. 17 Wednesday – Culemborg – The Barbarakerk 18 St. Barbara's Church was built in the fourteenth century and burned down in 1654. After this, the church was rebuilt. It was originally a Catholic church, but during the Reformation , the church was given in 1578 to the Protestants. The church was restored between 1963 and 1968, and in 2012 underfloor heating was installed. The main organ was built in 1797 by Matthijs Verhofstadt. In 1971 the organ was restored. It is the best preserved organ by Verhofstadt. In 1967 an organ by an unknown builder, previously used in Naarden and Baan, was placed in the choir. The tower contains a carillon with 47 bells. 19 20 Pijpwerk 1719 (manualen) en 1971 (pedaal), tenzij anders vermeld. (II) C-c3 Bourdon 16 - C-G eiken, vervolg lood Prestant 8 - C-c2 front, vervolg op de laden Holpyp 8 Octaaf 4 Holfluyt 4 - C-c0 gedekt, vervolg met roeren Quint 3 Superoctaaf 2 Nasaat 2 - C-f1 roergedekt, vervolg open Mixtuur IV Cimbel III - 1959/2013 Sexquialter III discant. Grotendeels 1719 Cornet IV - discant Trompet B/D 8 - Stevels 1959, koppen 2013 (CH)/1959; kelen, tongen, bekers 1719/1833 C-f1 Subbas 16 Octaaf 8 Octaaf 4 Fluyt 2 Trompet 16 Trompet 8 Schalmey 4 HOOFDWERK PEDAAL WERKTUIGLIJKE REGISTERS Manuaalcoppel Pedaalcoppel - naar het Hoofdwerk Tramblant Hoofdwerk Tramblant Onderpositief STEMTOONHOOGTE: a=415 Hz STEMMINGSSYSTEEM evenredig zwevend. (I) C-c3 Holpyp 8 - C-G eiken, vervolg lood Prestant 4 - C-dis in het front, vervolg op de lade Holfluyt 4 - gedekt Octaaf 2 Quint 1 ½ - grotendeels 1971; H, f2-F`#2 (sinds 1988) pijpen uit 1719 Mixtuur II - 1971 Sexquialter II - discant. 1971 Vox Humana B/D 8 - 2013 ONDERPOSITIEF 21 Koororgel restant 8 D Holpyp 8 Prestant 4 Octaaf 4 B/D Holfluyt 4 Quint 3 Octaaf 2 Mixtuur 2 st. B/D Cimbel 2 st Sexquialter 2 st. D Dulciaan 8 22 Thursday Leerdam. The Great Church was founded in 1250, built of bricks. In the second half of the 12th century a stone tower was built in the Romanesque style. In the 15th and 17th centuries the height was increased. The lantern was added in 1850 and the balustrade in 1857 – 1960. After the completion of the tower the church space itself has been enlarged several times: Between 1400-1450 they built a north and a south transept transept, making it cruciform. Between 1450-1500 chancel choir was raised higher and higher with a fan vault; and a sacristy was added. Both were built in Gothic style and decorated with so called 'fat layers of stone. Between 1500-1525 the north transept was broadened and in 1550 the original nave was replaced by the current pseudo-basilican construction with side-aisles flanking the tower. 23 The Witte organ was built between 1852 and 1854. It has 22 stops, two manuals and pedal. In the next half century, repairs and modifications took place. In 1957, as a major restoration of the church took place, the organ was taken down and completely restored by Willem van Leeuwen, including a return to an earlier disposition. The disposition was now again totally Witte's. In 1997 the organ was restored by the firm of Pels & Van Leeuwen, with the advice of Aart Bergwerff. 24 25 Hoofdwerk: (C-f3) Prestant 16 Prestant 8 Bourdon 8 Octaaf 4 Fluit 4 Quint 3 Octaaf 2 Mixtuur 3-5 Cornet 5D Trompet 8 Bovenwerk: (C-f3) Prestant 8 Roerfluit 8 Viola 8 Salicet 4 Roerfluit 4 Gemshoorn 2 Dulciaan 8 Pedaal: (C-d1) Subbas 16 Octaafbas 8 Octaaf 4 Trombone 8 Koppeling Bw-Hw Koppeling Bw-Ped Koppeling Hw Tremulant 26 Thursday - Heukelum 27 The Bätz organ (1779) Bourdon 16 B / D Prestant 8 Holpijp 8 B / D Flute travers 8d Octave 4 Gemshoorn 4 Quint 3 Octaaf 2 Mixture strong III-VIII B / D Cornet IV Trompet 8 B / D (Blank, 1969) https://www.youtube.com/watch?v=dPWyqoJjNJk 28 Thursday - Gorinchem 29 C.G.F. Witte, 1853 with some pipes from J.H.H. B䴺, 1761 30 Bovenwerk C-f3 – in zwelkast uit 2007 Prestant 8 Hoofdmanuaal C-f3 Prestant 16 – deels 1761 Bourdon 16 – deels 1761 en 1830 Prestant 8 – deel 1761 of eerder Roerfluit 8 – 1761, d#3-f3 1853 Octaaf 4 – 1761, d#3-f3 1853 Nachthoorn 4 – 1761, d#3-f3 1853 Quint 3 – 1761, d#3-f3 1853 Octaaf 2 – 1761, d#3-f3 1853 Mixtuur III-IV-V – 16’-basis in 2011 gereconstrueerd Scherp – II-IV2011, in Witte-factuur Cornet V – discant Fagot 16 – bekers, koppen en stevel 1761, rest 1853 Trompet 8 – bekers, koppen en stevel 1761, rest 1853 Baardpijp 8 – deels 1761 Quintadeen 8 – deels 1761 Viola 8 Roerfluit 4 Salicet 4 Nazard 3 – deels 1761 Woudfluit 2 – deels 1761 Carillon III – 2008 Schalmij 8 – deels 1761 (bekers, koppen, stevels) Vox Humana 8 – deels 1761 (bekers, koppen, stevels) Pedaal C-d1 Prestant 16 Rugpositief C-f3 Prestant 8 Subbas 16 Holpijp 8 Octaafbas 8 Fluit travers 8 – reconstructie 2011 Octaaf 4 Quint 3 Gedekt 8 – 2002 Roerquint 6 – 2002 Octaaf 4 – 2002 Bazuin 16 Octaaf 2 Trombone 8 Mixtuur IV Trompet 4 – 2002 Fluit 4 Cornet V Trompet 8 Dulciaan 8 – 1960 Werktuiglijke registers Koppel Hoofdmanuaal – Bovenwerk Mixtuur III-IV-V C: 2 – 1 1/3 – 1 Koppel Hoofdmanuaal – Rugpositief – 1981 Pedaalkoppel Hoofdmanuaal F#: 2 2/3 – 2 – 1 1/3 – 1 Pedaalkoppel Rugpositief f#1: 5 1/3 – 4 – 2 2/3 – 2 – 1 1/3 Tremulant Hoofdmanuaal – 1960 Tremulant Rugpositief – in 1980 vernieuwde tremulant van 1960 Tremulant Bovenwerk – in 1960 vernieuwde tremulant van 1853 Afsluiters voor alle werken f#2: 8 – 5 1/3 – 4 – 2 2/3 – 2 Zweltrede Bovenwerk – 2007 c1: 2 – 1 1/3 1 – 2/3 f#: 4 – 2 2/3 – 2 – 1 1/3 – 1 Scherp C: 1 – 2/3 c: 1 1/3 – 1 – 2/3 c2: 2 2/3 – 2 – 1 1/3 – 1 Samenstelling nieuwe vulstemmen c3: 4 – 2 2/3 – 2 – 1 1/3 Wind pressure – the whole organ 79 mm http://www.pleasuresofthepipes.info/Gorinchem-GroteKerk.html http://www.gerbenbudding.nl/grote-kerk https://www.youtube.com/watch?v=VjH78jqDgAU 31 Friday - Utrecht 32 33 Friday Museum Speelklok Witte 1883 Hoofdwerk [II] C-f3 Prestant 16' Prestant 8' Roerfluit 8' Violon 8' Octaaf 4' Fluit 4' Quint 3' Octaaf 2' Mixtuur III-V Cornet D V Fagot 16' Trompet 8' Positief [I] C-f3 Prestant 8' Holfluit 8' Quintadeen 8' Octaaf 4' Roerfluit 4' Doublet 2' Mixtuur III-IV Cornet D III Trompet 8' Bovenwerk [III] C-f3 Bourdon 16' Holfluit 8' Salicet 8' Viola 8' Fluit travers 8' Fluit 4' Salicet 4' Nazard 3' Flageolet 2' Schalmy 8' Dulciaan 8' Werktuiglijke registers koppeling HW-Pos koppeling HW-BW koppeling Pos-BW koppeling Ped-HW koppeling Ped-BW tremulant BW trede zwelkast BW treden voor afsluiten combinatiestemmen HW, BW en Ped 34 Pedaal C - d1 Prestant 16' Subbas 16' Octaaf 8' Bourdon 8' Quint 6' Octaaf 4' Bazuin 16' Trombone 8' Friday – Dom The present instrument incorporates parts of an earlier organ, the 1569 - 1571 Peter Janszoon de Swart renaissance organ. From this famous and capable organ builder 6 stops remain in the Rugwerk, 3 in the Bovenwerk, and 2 in the Pedal. The plenum formed by octaaf 4 and 2', the quint 3' and the two mixtures in the Rugwerk are by de Swart. In manufacture as well as in sound quality these pipes are the best of the organ. Due to the usual compass of instruments in the 16th century the old pipes are basically in the region F, G, A - f#2, a2, the remainder made new in 1640, 1709 and 1831. The Bätz organ company, one of the leading organ builders in the Netherlands during the 18th and 19th century, built a totally new instrument as we see it today in its present form, while using several old stops, as indicated above. Nevertheless the company created an organ in the style of the early 19th century, while the architect of the church, Tieleman Franciscus Suys from Brussel, Belgium designed the case and ornaments as well as the new chamber for the 9 wedge bellows. The case is neo-classic, with gothic elements for the ornaments. The organ itself is built in such a way that all parts such as pipes and mechanism can easily be reached. The famous French organ builder Cavaillé-Coll expressed his admiration for the spacious layout during a visit in November 1844. In 1865 the successor of Bätz, C.G.F. Witte exchanged the sexquialter of the Hoofdwerk for a Cornet 5 ranks and in 1895 this company revoiced all the reed stops. During the period between 1911 and 1936 the Tousijn 8' en Fluit 2' on the Rugwerk were removed, there was a renewal of the HW Trompet 8'. The Gemshoorn 4' and Woudfluit 2' were also removed and a swell box for the Bovenwerk was added. On the Bovenwerk the Roerquint 3' and Vox Humana 8' were exchanged for romantic stops, and finally in 1935 the bellows chamber was demolished and a new wind supply was improvised in the relatively shallow organ case. During the 1972-73 extensive restoration by Van Vulpen, the experts in maintenance and restoring Bätz organs, the stops which had been removed earlier were reconstructed. A new wind supply system ws built with six regulators within the main case, because there was no room left outside the organ for a system based on wedge bellows. The swell box was kept as a useful addition. 35 Hoofdwerk - man. II Prestant 16' a Bourdon 16' d Octaaf 8' f Roerfluit 8' Octaaf 4' h Gemshoorn 4' Quint 3'k Octaaf 2' m Woudfluit 2' Mixtuur bass/desc. 4-8st . Sexquialter desc. 4st. Fagot 16' Trompet 8' Rugwerk - man I. Prestant 8' b Holpijp 8' Quintadeen 8' Octaaf 4' g Roerfluit 4' Quint 3 'j Octaaf 2' l Fluit 2' Mixtuur 3-6st. Scherp 3-4st. Cornet desc. 5st. Trompet 8' Touzyn bass/desc. 8' Bovenwerk - man III. Prestant 8' Baarpijp 8' Holpijp 8' Viola de Gamba 8' Fluittravers 8' i Octaaf 4' Open fluit 4' Roerquint 3' Woudfluit 2' Flageolet 1' Carillon 3st. Trompet 8' Voxhumana bass/desc. 8' Pedaal Prestant 16' c Subbas 16' e Octaafbas 8' Fluitbas 8' Roerquint 6' Octaaf 4' Mixtuur 4 st. Bazuin 16' Trombone 8' Trompet 4' Cinq 2' tremulants for Rugwerk and Bovenwerk couplers: Hw/Rw, Bw/Hw, Hw/P, Rw/P Notes: bass/desc. =stop divided in bas and treble, treble starting at middle c a= two ranks from middle c# upwards b= two ranks from first D upwards c= two ranks C-A d= C-b0: wood e= all pipes wood f, g, h= two ranks from middle c upwards i= all pipes wood j, k, l, m= two ranks from middle c upwards Manuals C-f3, pedal C-d1 (extended in the virtual version up to an f1) All pipes from 1831, except: Rw: Quintadeen 8', Octaaf 4' , Quint 3', Octaaf 2', Mixtuur and Scherp = mostly from 1571, Roerfluit 4' = from 1700, Fluit 2' and Touzyn 8' = from1974. Hw: Sexquialter, Gemshoorn 4', Woudfluit 2' and Trompet 8' = from1974. Bw: Open fluit 4', Gemshoorn 2' (labelled Woudfluit nowadays) and Flageolet 1' mostly from 1571, Roerquint 3' and Voxhumana 8' = from 1974 P: Octaaf 4' 1571, Roerquint 6' from 1700. The drawstop called "Ventiel" is a device to empty the bellows. If drawn out, the hole to the main wind trunk is opened and the air easily escapes from bellows. 36 Saturday Amersfoort – Joriskerk 37 Choir organ New organ 1967 from Metzler & Söhne Manual Pedaal Quintade 16 Quintadeen 16 Prinzipal 8 (transmission) Gedackt 8 Octave 4 Pedal coupler Rohrflöte 4 Quinte 3 Manual compass C-f3 Octave 2 Pedal C-d1 Mixtur IV Trompete 8 38 39 De met * gemarkeerde registers zijn afkomstig uit het oude orgel. De Prestant 8 vt., Octaaf 4 vt. en Quint 3 vt. Bouwer: C.F.A. Naber, 1844/1845 Restauratie: D.A. Flentrop, 1972, 1991/1995 Hoofdwerk (C-f3) Rugwerk (C-f3) Bovenwerk (C-f3) Prestant 16 vt Prestant 8 vt Prestant1 8 vt Bourdon 16 vt Roerfluit 8 vt Holpijp1 8 vt Prestant 8 vt Bourdon 8 vt Quintadena3 8 vt Holpijp 8 vt Octaaf 4 vt Viola di Gamba 8 vt Octaaf 4 vt Holfluit 4 vt Octaaf1 4 vt Openfluit 4 vt Woudfluit 2 vt Fluit1 4 vt Quint 3 vt Sexquialter1 2 st Nasard 3 vt Octaaf 2 vt Mixtuur Gemshoorn 2 vt Flageolet3 1 vt Mixtuur 4-6 st Dulciaan2 3-5 st 8 vt Scherp 4 st Hoboe 8 vt Cornet D 5 st Voxhumana 8 vt Fagot Trompet B/D 16 vt 8 vt Pedaal (C-f1) Koppelingen Prestant 16 vt HW-RP Subbas 16 vt HW-BW Octaaf 8 vt RP-HW Octaaf 4 vt Ped-HW Bazuin 16 vt Ped-RP Trompet 8 vt Tremulanten op bovenwerk en gehele werk. Afsluiters voor HW, RP, BW en Ped. 1) uit 1551 2) Naber 1853, uit Vriezenveen 3) Flentrop 1972 Toonhoogte: a1 = 437 Hz 40 https://www.youtube.com/watch?v=rOGjkGrpvy4 https://www.youtube.com/watch?v=69BP3xIORvg https://www.youtube.com/watch?v=DzKkwGYeQUg https://www.youtube.com/watch?v=Pp_Ru9qBpFs https://www.youtube.com/watch?v=GJaZjH3-JtU https://www.youtube.com/watch?v=624VmH1Hbvs https://www.youtube.com/watch?v=qi1V6w-lR0U https://www.youtube.com/watch?v=f0BOhL4NRGM 41