July 2019 : Adding reverb to Hauptwerk

Most Hauptwerk virtual theatre pipe organ (VTPO) sample sets are dry (they have very little reverb), or semi-dry (have a small amount of reverb). Many classical and church virtual pipe organ (VPO) sets are also available in dry format. All these sample sets benefit from added reverb.

Reverb is one of the ways that our ears interpret the size of a room. In many ways, the room is part of what makes an organ alive – and by adding reverb we add that life by making the sound of the organ more spacious. The right reverb adds life – but when the effect is overdone then the sound becomes very muddy. We must also take personal taste into account here – as what I like and what you like can be quite different. If I’m used to playing in a small chapel and you’re used to playing in a large cathedral, then what sounds ‘right’ to me could be different to what sounds ‘right’ to you.

There are two ways of adding reverb to your Hauptwerk system:

External reverb – this is something that you plug into your speaker system between your computer audio output and your amplifier.
VST/AU software reverb – this adds reverb before sending the audio out of your computer.

External reverb modules:

Just to give you an idea of what I’m talking about here, look at the Alesis NanoVerb 2:

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It has audio inputs and audio outputs. You plug the audio cables from your pc into the inputs, it adds reverb, and then sends the mixed audio signals out of the module for you to connect to your amplifier and speakers. You select the style of reverb that sounds good, turn the mixing dials to increase or decrease the amount of the effect, and your system has reverb.

External reverbs are the simplest reverb option. The limitations are that there are not many great reverb modules available, and those that are available can be costly. If you're looking for an external reverb module, see if you can source one 2nd hand.

VST software reverb:

VST is an acronym for Virtual Studio Technology. It was pioneered by Steinberg (they released the first VST interface specification in 1996) and was created to make audio plugins possible through software. VST allows us to add reverb between Hauptwerk and our sound card. A virtual studio for our virtual pipe organ! Mac users can use VST reverbs as well as AU (Audio Units) plugins.

VST effects need host software to run, as they are plugins. Just like in a recording studio where you would have a physical rack of effect processors (like the reverb module above, and many other modules for other effects), so also in the virtual studio we need a virtual rack – and this is the VST host application. Some programs are just VST hosts, others combine being a VST host with the full suite of a Digital Audio Workstation (DAW). Cantabile is a good example of a simple VST host. Reaper is a good example of a DAW with VST options.

The VST host handles the audio settings and connection to the soundcard. So, when you use Hauptwerk with VST reverb you must set the Hauptwerk Audio Outputs settings to use the Hauptwerk VST Link.

In your VST host you then load the Hauptwerk VST plugin, which connects Hauptwerk to your VST host. You load your reverb effect plugin, make sure your audio signals are correctly connected, and the mixed Hauptwerk and reverb audio signals are then sent to your sound device.

If you have the Advanced version of Hauptwerk then you can use the multiple audio channel options and have multiple reverb effects, such as loading two instances of the Reverberate LE plugin, and then routing the ranks of one chamber into the first instance with one set of reverb options, and routing the ranks of the other chamber into the second instance with a different set of reverb options.

Using VST reverb means that you use more CPU resources, so if you don't have a powerful computer then use a reverb program that does not use a lot of resources, like MVerb. Many of the VST reverbs referenced below use convolution reverb - which uses a recording of a real or modeled space to create the initial reverb parameters. These provide a very real 'feel' as they are based on those recorded impulse responses of real places.

As your VST host handles the connection to your audio device (sound card), make sure that your audio settings in your VST host are tweaked to allow for the best balance between low latency and no audio glitches.

I use SIR2 (no longer available as SIR3 came out) on our home console, and use MVerb on three VTPO consoles that I manage here in Johannesburg.