Hauptwerk

Released 2002

• Available for Windows only
• Stops operated by MIDI Note messages
• Simple Swell simulation (volume only)
• Organ of St Annes, Moseley included

Released 2006 [5]

• Available as VSTi plugin
• More flexibility in MIDI configuration
• Phase alignment of release samples
• Harmonic Swell simulation

Released November 2007 [6]

• Support for Mac OS X
• Support for Multiple Touch-Screens
• Voicing Control for individual pipes

Released April 2011 [7]

• Redesigned User Interface
• Automatic facility to configure MIDI to support most manufacturers
• Inbuilt MIDI recorder/player
• User defined Combinations/Crescendos
• Master Couplers available with all organs

Released December 2019

• Redesigned Audio Output Routing
• 3D Sound output
• Impulse Response reverb capabilities
• Removed Free Edition

Released November 2020

• Menu changes
• Combination system changes
• MIDI changes
• Audio engine changes
• Small changes + bug fixes[8]

The recorded samples of the original pipes are divided into 3 main sections - start(attack), middle(sustain) and end(release or echo). When a note is played the attack sample is played followed by a loop of the sustain section. Start, end and release loop points are stored in the recorded sample file. When the note is released, the release or echo section of the sample is used, or specific release sample files can be defined for a note, or range of notes. This latter feature is useful in making the organ more realistic, for example the echo of a pipe after a short period will be different from that of a pipe that has been sounding for longer. Hauptwerk can select from multiple release samples based on the duration of the note. Tremulant effects are possible using LFO sample files to dynamically modify the sound, avoiding the need to create individual tremulant note sample files.

When an organist moves an Expression pedal it affects both the volume and frequency envelope of the affected pipes. Hauptwerk adjusts both of these parameters using information provided within the sample-set. This can be based on measurements taken from the original instrument.

The wind-pressure applied to an organ pipe affects its volume, pitch and character. Hauptwerk uses Fluid dynamics to model the movement of air through the various parts of a pipe-organ. This information is then used to modify the sampled sound.

Randomization is used to modify certain aspects of the audio output. The pitch of individual pipes can be randomly modified when a sample is loaded into memory. If multiple loop points are provided, in the sustain section of a sample, these are selected randomly. Additionally, Hauptwerk simulates some other effects, such as Wind Turbulence, using Randomization during playback.

In March 2009, Milan Digital Audio announced that permission had been given to record the Father Willis organ at Salisbury Cathedral, UK.[11]

Starting 23 February 2010 the Salisbury Cathedral pipe organ was temporarily unavailable, due to maintenance work scheduled to last one month. During this time a console based on Hauptwerk was used to provide organ music for cathedral services.[12][13]

According to an article on the Salisbury Cathedral website: "Over the past few weeks we have used the organs from Metz Cathedral, France, St Georgenkirche, Roetha, Germany, and Our Lady of Mt. Carmel, Chicago, IL., USA". The article continues: "Volume I of our very own Father Willis Organ was released by Milan Digital Audio just days before my organ was installed into the cathedral which has allowed me to use 28 of the 65 stops of the Father Willis organ in its natural acoustic. It is believed to be the first time a sampled instrument has been used in its own building for services!"[14][15]