Altenbruch, Klapmeyer Organ

Klapmeyer organ, Altenbruch, 1727-1730

The St. Nikolai church in Altenbruch owns one of the oldest North German organs. In 1497-1498, Johannes Coci built a small organ of 6 stops. It stood near the main altar. Matthias Mahn enlarged the instrument in 1577 (or 1561?) by adding a Rückpositiv.Today, some of the Coci organ's pipes are still incorporated into the RP Gedact 8', OW Quintadohn 16', and Pedal Untersatz 16'. Other pre-1647 pipe material is to be found in the RP Principahl 8', Octav 4', Nasat 3', and Blockfloit 2'. 

In 1647, Hans Christoph Fritzsche renewed the organ, enlarging the Hauptwerk as well. The Principal plenum of the Hauptwerk (called also the Oberwerk) is formed from his pipes today. His pipes also sound in the Quintadöhn 8', Gedact 4', Sexquialtera, and Mixtur of the Rückpositiv. Matthias Dropa expanded the compass of the instrument in 1698 and provided additional stops, especially in Pedal. His pipes still sound today in the RP Kromhorn 8', Octav 2', Pedal Gedact 8', Octav 4', Mixtur, Posaun 16', and Trometh 8'. A few decades later, the church was rebuilt and a west choir was added. Consequently,  Johann Hinrich Klapmeyer (1690-1757) was commissioned to relocate the organ into a newly constructed west gallery. The organ was substantially reworked as well between 1727-1730. The organ builder added new Pedal towers and supplied the Pedal Principal 8'.  He also inserted a new Brustwerk of 6 stops under the chest of the Oberwerk, and he added new reed stops to the Oberwerk:Trometh 8' and Vox humana 8'. Klapmeyer provided the organ with its present look. The organ survived until the present mostly unchanged. It was restored in 2004 by the Ahrend organ workshop.

The organ consists of three manuals and a pedal: altogether 2100 pipes and 35 sounding stops. The presence of 3 independent Principal 8 stops (in Oberwerk, Rückpositiv, and Pedal) is one remarkable feature of this instrument. It is a stylistically pure instrument and emblematic of the North German organ building school. The so called Hadeln liturgy adopted in 1567 anticipated the use of the organ as a solo instrument, thus contributing to the elevated art of the organ building and organ use in the Altenbruch church. The organ is especially suitable for early North German music, such as the work of H. Scheidemann, M. Weckmann, F. Tunder, and D. Buxtehude.



The samples are offered in 48kHz/24bit resolution. The multiple releases have three levels: short, mid and long. Hauptwerk v. 5 and higher supported. The Surround variant of the sample set is encrypted, which means that it can be used with Hauptwerk Basic or Hauptwerk Advanced versions exclusively. Hauptwerk Advanced version is strongly recommended, the Basic version is not suitable to run the Surround variant of the sample set (memory limitations, audio channels limitations). There is no use of the sample set possible in any other software.

The SemiDry variant of the sample set is offered unencrypted, in plain wave format. It may be loaded in Hauptwerk 4.2 and higher (including HW5).

Reverb time

The reverb time is ca. 2 seconds.

Keyboards, pedalboard

The original compass of the keyboards is 45 keys (4 octaves, lowest short).  The original compass of the pedal division is 25 keys (no low C# and D#). The compass was extended in the extended version of the sample set so that the manual compass is 4 octaves (51 keys C-d3), and the pedal bass octave was completed, so that the pedal has 27 keys (C-d1).


All ranks of all the divisions were recorded with and without tremulants for the most convincing tremulant behavior. The Rückpositiv stops were recorded with the Rückpositiv tremulant (faster) and also with the general tremulant (slower). Both recorded versions of the tremmed samples are included in the sample set. However, loading the authentic tremmed ranks consumes large amount of RAM. It is possible to select to use the artificial tremulant instead to save RAM (the switch is located on the mixer tab).


RAM consumption: 6-channel surround

  • 16-bit, other settings default:   20.8 GB

  • 20-bit, other settings default:   39.9 GB (recommended)

  • 24-bit, other settings default:   48.4 GB

  • To load the instrument into a PC with 32 GB of RAM limit, load everything in 20 bits, except Pedal in 16 bits. Alternatively, load everything in 20 bits, but disable some not-commonly-used tremulant samples, like tremulants for mixtures of all the divisions, Untersatz and similar.

RAM consumption: 2-channel wet or semiDry

  • 16-bit, other settings default:   7.4  GB

  • 20-bit, other settings default:  15.1 GB

  • 24-bit, other settings default:  17.1  GB

Screen resolution 1280x1024 px or more.

Polyphony of 4000 voices recommended for the full suround (2500 pipes minimum).

Polyphony of 1800 simultaneous pipes recommended for use of the wet or semiDry sample set.

Surround format

The sample set is offered in the Surround variant (6 channels). In addition to the usual 4-channel surround, there are two more alternative front channels. In total, there are 4 front audio channels and 2 rear channels. The two pairs of the front ranks feature two different recording positions: direct (near to the pipes) and diffuse (distant from the instrument). These two pairs of the front ranks can either be mixed together freely to achieve any listening position between the two extremes, or used separately - depending on the prefererences of the user. A dedicated "mixing desk" is available in Hauptwerk to mix the sound to the desired level.


  I Rückpositiv CDEFGA–c3  
  Principahl 8′  
  Gedact 8′  
  Quintadöhn 8′  
  Octav 4′  
  Gedact 4′  
  Nasat 3′  
  Octav 2′  
  Blockfloit 2′  
  Sexquialtera   II  
  Mixtur IV  
  Dulcian 16′    
  Kromhorn 8′  
  II Oberwerk CDEFGA–c3  
  Quintadöhn 16′    
  Principahl 8′  
  Gedact 8′  
  Octav 4′  
  Waldfloit 2′  
  Mixtur V  
  Cimbel III  
  Trometh 8′  
  Vox humana   8′  
  III Brustwerk CDEFGA–c3  
  Gedact 8′  
  Gedact 4′  
  Octav   2′  
  Quint 11/2′    
  Scharff III  
  Knop Regal 8′  
  Pedal CDE–d1  
  Untersatz 16′    
  Prinzipahl   8′  
  Gedact 8′  
  Octav 4′  
  Mixtur IV  
  Posaun 16′  
  Trometh   8′  
  Corneth 2′  
  • Coupler III/II
  • Tremulant RW, Tremulant General
  • Cimbelstern
  • Ventil for each division
  • Wind: 77 mm
  • Pitch in Chorton, a1 = 478,5 Hz at 18 °C   [471,2 Hz at 14 °C when recorded for Sonus Paradisi]

The temperament is described as "Werckmeister III modifiziert". By measuring the real existing pitch of pipes at the time of the recording, we arrived at this cent deviation table:

 C     C#     D     D#     E     F     F#     G     G#     A     A#     B 
0    -10.2     -2.7     -7.1     -9.9     -2.8     -11.3     -0.8     -7.4     -7     -3.9     -8.4 







Console view:

this is the general console view. It serves to define the keyboard MIDI inputs for all the divisions. The only active part of this view are the manuals and the pedal. Specifying the MIDI inputs is done by right-clicking on the desired manual or pedal.

All the other screen components are image-only. 




Mixer view:

The virtual listening position is adjusted here. Dragging the sliders downwards means to come closer to pipes (more direct sound), dragging them up means going away from the organ into the church nave.

The mixer settings can be stored, retrieved, reset. 3 different mixer settings can be stored/recalled any time.

The switch in the right makes the selection for the tremulant between the sampled tremulant and artificial (Hauptwerk model) tremulant.





Left+Right Jambs view:

for dual touch screens, split jambs were created. They allow for portrait or landscape orientation, according to the orientation of the touch screens.




Left + Right Jambs Vertical view:

the dual stop jambs offer vertical (portrait) orientation as an alternative.



Single Jamb:

All the stops and other controls of the organ can be found here. 

Physical pistons or draw stops can be assigned to a virtual button on screen by right-clicking on the button.

Note to the right click: The Single jamb, the Split Jambs and the Simple jamb, all allow for right-click to attach a specific MIDI hardware button to any of the software switch. This is done so that several different MIDI hardware buttons can operate one single software switch, so that the user can operate one stop or one and the same coupler with more than one hardware pistons.




Simple Jamb:

simplified version of a single jamb to allow for more readable version of the stop names on small LCD touch screens.




Altenbruch Surround - v.1.4 update

  • A number of releases adjusted for smoother crossfade, especially reeds.
  • Several misbehaving tones in reeds better voiced.
  1. Altenbruch Surround Sample Set - SemiDry + Surround

    Altenbruch - Bundle of Semi-Dry + Surround variant. 6-channels. Encrypted, Hauptwerk dongle protected. For HW5 or higher.
    €400.00 Excl. Tax

    Detail & order

    Original price: (excl. tax)€500.00
    Bundle sale (20%):
    - €100.00
  2. Altenbruch Surround Software Sample Set

    Altenbruch - Surround variant. 6-channels. Encrypted. Minimum Hauptwerk version: 5. (Also works in all higher versions.)
    Price: Excl. Tax: €300.00 Incl. Tax *: €363.00 Excl. Tax

    Detail & order

  3. Altenbruch SemiDry Software Sample Set

    Altenbruch - SemiDry variant. 2-channels. Plain wave format. Minimum Hauptwerk version: 4.2. (Also works in all higher versions.)
    Price: Excl. Tax: €200.00 Incl. Tax *: €242.00 Excl. Tax

    Detail & order