Hauptwerk 5 with true-to-life reverberations of the church

Hauptwerk is designed to play in the living room with the sounds of the church organ.

Most people who want to buy an organ expect sounds as they have heard them as a listener in the church. However, so far from the organ, the sounds are already strongly concealed by the reflections in the acoustics of the church. An organist would not be able to play the organ at that distance, because the characteristic properties of the sounds are missing. The moment the organist presses a key, the tone starts with a clear accent and then builds up to the full tone. He (she) must hear that immediately, even before the tone is concealed by the first reverberation of the acoustics. It is part of his rhythm, his tempo, his phrasing. Everything he wants to express with his music is only possible if the tones are heard directly under his fingers.

Hauptwerk organs use the sounds that are recorded in the samples. Many of these samples are recorded at a great distance from the pipes and contain more reverb than pipe notes. My house pipe organ produces beautiful sounds, but lacks the acoustics in the living room. It is a strong point of Hauptwerk that the full acoustics of the church can be heard, but that should not be at the expense of the direct sounds, such as the organist them close to the organ hears.

With Hauptwerk 4, the sound experience of the organist was not easy to transfer to the living room. The microphones were set up so that both the pipe tones and the reverberation were included in the samples, but both tones suffered greatly from the big compromises. Dividing it into two microphones at the front of the church and two at the back, so as four-channel recordings, is just as unsatisfactory. In the front recordings, the tones are already too concealed and the recordings at the back do not replace the acoustics.

The only way to properly store the real pipe tones in the samples is to place the microphones as close to the pipes as possible; the DRY samples. Hauptwerk 4 used remote recordings; those are the infamous WET samples to suggest reverberation. But real reverberation starts at the source, the pipes! and moves away from the source until it dies far away. Reverberation from WET samples is coming to the source, which is the wrong direction. Amateurs accept these sounds as the real reverberation. As listeners in the church, they have never heard otherwise.

In Hauptwerk 5 a new technique has been realized that transfers the sound experience of the organist in the church to the living room. The sample set may only contain the pipe tones without the reverb, so the normal DRY samples. The reverberation is recorded separately with IR technology and is stored as a complete copy of the acoustics of the church in a memory. All aspects that the pipe notes undergo through the reverberation in the church now take place in the Hauptwerk organ. An organist has the same sound experience in the living room as in the church. Amateurs have to get used to the direct sounds, they now play a pipe organ and are no longer the audience in a church.


Surround was popular in Hauptwerk 4. This required many WET sample channels and a room full of speakers. When I give a demonstration with the new Hauptwerk 5 technique, the visitors are surprised that two channels transfer the sounds as well the acoustics of the church realistically into the living room. The sounds do not come from an identifiable direction but are present all around. This achieves what was expected of surround.    

A church with good acoustics

The sounds I hear in my living room are the same as what the organist hears in the church. Two channels that together form a single stereo channel are sufficient to display the organ in the church, which is even one source of sounds, in the living room. The function of the organ cabinet is to bundle the sounds into one source. It is impossible to determine where the pipe is at that moment. A distribution of the pipes in C- and Cis side is done to distribute the weight of the organ, but a good organ cabinet prevents the direction from being audible. There is only one source of sounds. If the acoustics of the church are good, the whole room will be filled with sounds, without an apparent direction.

As example the two organs of Bedheim (East Germany). They are placed in two organ cabinets, one in front of the church and the other hangs at the back like a Swallow nest organ on the ceiling. The two keyboards are in the main organ. The sounds merge completely and in no place in the church can be determined from which organ they come from. The acoustics unite the sounds into an all-around sound.

As a pipe organ builder and voicer, I have played the organ in hundreds of churches in Europe. I know the specific differences between North and Central German organs, as well as the Swiss and Italian organs. In all these styles I have made pipes and voiced them to the sound of that style. When DRY samples have been made of these sounds, I can also voice them and there is no difference with the sounds of that organ in the church. To display my Hauptwerk organ, I use one stereo channel with DRY samples and the reverberation recorded as Impulse-Response.

According to Silbermann, the organ sound is a balance between Power, Clarity and Poetry.
A Principal plenum will sound powerful and transparent and fill the entire space. The poetry can be found mainly in lovely tones, such as a four-feet Flute that sounds thin in a seemingly limitless space. The sounds are present all around and do not seem to come from a certain direction. This is the realistic representation of the church organ that cannot be matched with multichannel WET samples.

Organists who rejected Hauptwerk after hearing a Hauptwerk 4 multichannel organ, played my organ with enthusiasm. The sounds and reverberations are heard in the church. Moreover, my pipe organ is next to compare the sounds. Unfortunately, the house pipe organ lacks the necessary reverberation, making the Hauptwerk organ preferred.

book Martini
Characteristic sounds

The most important part of a pipe tone is the beginning, the moment when the pipe starts to form its tone. It is the articulation that the organist needs for his musical expression, as is the case with any musical instrument. When the wind from the languid gap reaches the upper labium, there is an underpressure that draws the wind in. This results in an overpressure in the pipe that pushes the wind out again. see Prestant

This swirling wind gives a clear asccent to the tone. The accents differ according to the nature of the register, a Principal starts differently than a Stopped Diapason. The microphones must be a short distance from the pipes to capture the character in the DRY sample or the important part of the sound will not be heard. Sometimes it is not possible to get the microphones in the ideal place and it becomes a semi DRY sample, but with the wide possibilities that Hauptwerk offers to adjust the sounds, the articulation can still be heard.

In normal playing, the articulation and the first moment of tone formation is the only thing that is heard from the organ sound. It is therefore important that this is properly recorded. I have played a lot in churches in southern Germany and in Switzerland with a huge reverberation and then the acoustics of the empty church are were annoying. Then I am happy that the church fills up and dampens the acoustics.

I made the convolution reverberation of my Hauptwerk organ adjustable with the left pedal, so that it can always be adjusted to the music.