How to add reverb?

The dry sound of an organ is not really satisfying for many people. It is recommended by specialists, that an organ should be placed in a room with at least 2 seconds of reverb. Only then, its sound starts to be pleasing. If you need to add digital reverb to your dry virtual organ, what can you do?

VST convolution reverb

I recommend using VST plugins for convolution reverberation. I myself use Voxengo Pristine Space. But there are more plugins of this type, just make sure that the one you choose is able to work in real-time with low latency. We tested the Litomysl dry sample set with following VST effects:

• Audioease Altiverb: many built-in impulses with a wide range of adjustable settings.
• Waves IR-1: many impulses available, wide range of adjustable settings.
• Wizoo Wizooverb: very good, wide range of impulses available.
• Ch. Knufinke SIR: freeware VST convolution reverb. Basic features, fixed latency, you have to feed it with your own impulse responses.
• Voxengo Pristine Space: VST convolution reverb, the best I found. You have to feed it with your own impulse responses.

Impulse responses

You need impulse responses, representing the reverb of halls, churches or any other spaces you like. Several plugins offer built-in IRs. If not, you can find various impulse responses on the web. Alternatively, you can buy some from vendors, or you can measure impulse responses yourself! We also offer impulse responses of our own production.

Hauptwerk and VST plugins

You have the VST plugin, you have the impulse responses, now you have to combine these with Hauptwerk to get the result. Since Hauptwerk is not - to my knowledge - currently capable of using VST effects, you have two ways:

 - Use Hauptwerk as a VSTi instrument and apply the VST reverb plugin to its track - I have no experience with this.

- Use Hauptwerk as a stand alone application but redirect its output to other software which will take care of the rest. I myself tried using software called Reaper  for this. It is an audio recording software - shareware (friendly priced). The nice thing about Reaper is, that it provides a virtual ASIO driver Rearoute with 16 channels which can be used as an audio output for Hauptwerk. The sound from Hauptwerk is thus redirected to Reaper where you can apply any VST effects to it sending the wet sound to your sound card.

Practical hints when connecting Hauptwerk and Reaper via Rearoute

The demos currently published were made using this technique:

1. Midi files were fed with MidiYoke into Hauptwerk
2. The output of Hauptwerk redirected to two channels of Rearoute
3. These two channels of Rearoute were captured in Reaper into one stereo track
4. This track was embellished with the VST effect Pristine Space and the result was recorded. I used the true stereo, i.e. 4 channels interconnected 2x2, using the true stereo insert preset. I used self-made artificial impulse responses.

For a "surrond" 4D sound, follow this technique:

1. Capture the same Hauptwerk output in the Reaper at least twice.
2. Use the first stereo track to supply the dry sound only. Apply equalizer and stereowidth control VST effects (both available in standard Reaper installation) to deal with the frequency filtering and panning width when changing the virtual listening position - the farther you go from the organ, the narrower the panning should be and the higher frequencies have to be damped.
3. Capture the same Hauptwerk output second time by Reaper using a different track. Apply the Pristine space to this track, but this time  use the preset true stereo send - i.e. the dry sound has to be muted. The marvelous thing is that you can send the reverb into different physical speakers than the dry sound and so you can separate the dry sound from the reverb in your room which gives quite nice 4D effect. Of course, you can capture the Hauptwerk output into as many tracks as you can until you use all your speakers up and you can surround yourself with reverb as in the real church - just repeat this point as many times as you wish using different tracks in Reaper. The impulse responses may vary and so the sound is really live and the sound field moves around your head nicely (I call this intentionally 4D since usually people call the two dimensional stereo or binaural sound 3D... and this setting still adds at least one another dimension:-))))

Reaper settings download

I have prepared two Reaper project files (*.rpp) which you can load directly into your Reaper and you will get most work with audio routing done. These projects are representing the surrond sound of the virtual Litomysl catherdral church. I used the demo impulse responses which are available for free download on my web page to allow for free experimenting. Normally, I would use high quality impulse responses which you can buy from our web pages as well.

The two Reaper projects feature essentially the same virtual church. What changes is the virtual listening position. The first file called Litomyslcathedral_surround_organist offers the possibility to hear the organ as the virtual organist does. The organist sits facing the organ which is located in one-block case on the organ loft. The nave of the church is behind the organist's back. Therefore, the dry sound of all the divisions goes to the front speakers. The wet sound goes to both, front and rear speakers with gradual predominance of the rear speakers to simulate the reverb "rolling" down the nave.

The second project (Litomyslcathedral_surround_audience) features the listening position of the audience down in the nave. Therefore the dry sound of the pipes is attenuated and the level of the reverb changes to give more "space" to the sound.

You can download both files from here and load them into Reaper. To get the expected sound, you have to check the prerequisities listed below. The screenshots will help you to go through the settings successfully.

Presuppositions:

When installing the Reaper, make sure that you select the "Rearoute" option - it is not selected by default!!!
Litomysl Dry Set has to be loaded into Hauptwerk. All ranks routed to the Main audio output which uses the ReaRoute ASIO driver as the Audio device and its channels ReaRoute Client=>Reaper 1 + 2.
You have to configure the Audio Device in the Reaper Preferences to your sound card with at least 4 channels. (In the example here, I am using the NVIDIA ASIO driver for the soundcard on the mainboard of the testing computer).
You have to have PristineSpace installed in the default directory specified in the Reaper settings.
You have to have the proper impulse resonse pairs installed in any directory of your hard drive and you have to specify this directory as the Search Path (currently set to I:\impulz\) of the PristineSpace settings - this is necessary so that Pristine Space loads the impulse response correctly. The impulse responses in question are: ChA 15 long tx (left and right) and ChA 15 long (left and right). The demo versions of these impulses are available from this web page.

Understanding the LitomyslCathedral_surround Reaper project.
 

Start Reaper and load the project which you downloaded from this web page. There are 3 tracks used. All of them are receiving the Channels ReaRoute 1 and 2. (These two channels are configured to send the sound from Hauptwerk as previously explained.) The first track is used to supply the wet (reverberated) sound for the front speakers. The second track supplies the dry sound for the front speakers. The front speakers are assumed to be the speakers for the Master section of the Reaper Mixer. The third track is used to supply the wet sound for the rear pair of your speakers.
Clicking the I/O button (the green button) of the Master section of the mixer, you can check if this master is send to the Left/Right front speakers of your soundcard (it is the default setting).
Clicking the I/O button (the green button) of the track no. 3, you can check if this track is send to the rear left and rear right speakers of your soundcard.
Now, you can change the characteristics of the surround sound according to your wishes. The tracks no. 1 and 3 use two effects: Pristine Space and Equalizer. Clicking the FX button (the blue button) of the track in question, you can display the effects and their setting. Feel free to experiment with various settings of Pristine space and of the Equalizer. The track no. 2 uses two effects: Stereo enhancer and Equalizer. The farther you go virtually from the organ, the narrower the stereo space have to be and the higher frequencies have to be attenuated.