The convolution engine in Hauptwerk can provide nice enhancement to older wet/surround sample sets, especially when the recorded tremulants are missing. The Hauptwerk tremulant model sounds a hundred percent more convincing when IR reverb is applied to the artificial tremulant.
Aarnoud de Groen experimented with the Zwolle surround sample set and the Sonus Paradisi IR collections, and provided audio examples demonstrating his enhanced tremulant discovery.
First, listen to the original Zwolle surround recorded, unaltered. This is how the sample set sounds when you load it into Hauptwerk with all the options default.
Now, replace the original recorded reverb with the convolution reverb in Hauptwerk.
First load the sample set with the releases truncated. The result sounds weird, listen to the example.
Now apply the convolution reverb of your choice to the samples. Innumerable possibilities exist. The easiest variant for the 2 channel output is to load only the front samples truncated and apply one IR to the whole sample set. Even this simple technique provides nice enhancement of the tremulant model. Zwolle IRs (collection called Zw74) were used in the audio demo. However, any IR collection may be suitable.
- Zwolle front, truncated, IR Zwolle omni RWLR
- Zwolle front, truncated, IR Zwolle omni BPLR
- Zwolle front, truncated, IR Zwolle cardio BPC
If the surround (4 channel) sound is to be achieved, the front samples and the rear samples must be routed into two different output buses, and each of the output buses must receive different IR from the same collection, the front ranks are asking for a front IR and the rear ranks want a rear IR. Sonus Paradisi IR collections usually contain the front and the rear IRs.
More complex mixer routing allows to apply appropriate IR to each of the different divisions of the organ (or even to the different groups of pipes within a division). The following audio example uses a complex routing which is explained in the PDF document at the end of this article:
- Listen to the audio demonstration of this complex routing, mixed into a single headphones output.
- Learn how to make the per division routing in Hauptwerk (PDF).
- Download all the audio files in this article in the original WAV quality.
I am grateful to Aarnoud de Groen for providing the audio examples.