Aeolus Quickstart Guide

by Steve A

Hello, and welcome to the 64 Studio quickstart guide for Aeolus, a sound application available in 64 Studio version 2.0. Aeolus is a synthesised pipe-organ instrument written by Fons Adriaensen. The default sounds have been skillfully programmed and are very realistic; this means that Aeolus can be very satisfying to play, or to listen with your favourite MIDI files. In this guide I will be showing you how to get Aeolus running with 64 Studio for the first time.

The first thing to know is that the 64 Studio version of Aeolus is configured by default to work with JACK, and this means that Aeolus will only work if the JACK server is started. So to begin, select "JACK Control" from the "Sound & Video" menu, and check that JACK is started.

jack started

Next, start Aeolus from the sound & video menu. Aeolus will take a few seconds to start, during this time each blue button will flash. When this process is complete, the Aeolus main window will be shown.

aeolus started

Next, connect a MIDI keyboard to your 64 Studio system, and select the instrument to play on the lowest-numbered MIDI channel. Please remember that some instruments number their channels from 0 to 15 and some number from 1 to 16. Select the lowest-numbered MIDI channel, (either 0 or 1).

If you don't have a MIDI keyboard, you could use VKeyBd from the Sound & Video menu. Within VKeyBd select View -> Controls.
This will allow us to set the MIDI channel used by VKeyBd. VKeyBd's channels are numbered from 0 to 15, so we will select the lowest channel which is 0.

vkeybd started

Next, we use JACK Control to connect the keyboard to Aeolus, and to connect Aeolus to the sound card. Switch to JACK Control and select Connect -> MIDI to make a connection between our MIDI keyboard and Aeolus.

connect MIDI

Then select the Audio tab and connect Aeolus outputs to the left and right playback channels of the sound card.

connect audio

Almost finished! Next go to the Aeolus main window. Notice that the window is divided into four sections (III, II, I, and P). We will experiment with these in more detail later. Click on the blue button labelled "Principal 4" in section "I". The button will be white when selected.

aeolus principal 4I

To recap, we have used JACK to connect our keyboard to Aeolus and to connect Aeolus to our sound card. We set our keyboard to transmit MIDI commands on the lowest-numbered MIDI channel and we have selected the sound called "Principal 4" from Aeolus section "I".

The final stage is to tell Aeolus that data received on the lowest-numbered MIDI channel should be played by Aeolus section "I". To do this, go to the Aeolus main window and select MIDI. Notice that Aeolus numbers the sixteen MIDI channels 1 to 16, not 0 to 15. We will simply connect the lowest MIDI channel (1) to section "I" ( which is labelled Keyboards "I")

aeolus MIDImap 1

Finished! Go to the MIDI keyboard and begin to play. Aeolus should make the wonderful sound of the "Principal 4". In fact, you can experiment with any of the sounds from section I.

Once you've got the instrument up and running, you can go on to the Aeolus primer.

Aeolus primer

by Steve A

Hello, and welcome to the 64 Studio Aeolus primer. To configure Aeolus for the first time please refer to the Aeolus quickstart guide. This primer contains more information about how Aeolus emulates a real pipe-organ's sound and controls.

Organ stops in Aeolus

An organ stop is the "patch" which makes a particular sound. In a real pipe-organ, a stop is a family of pipes which make the same sound. The organist has a switch near the keyboard which allows them to patch each stop into the sound when needed.

In Aeolus, organ stops are represented as blue buttons. Each button normally contains two pieces of information: the name of the sound, and a number. The number represents the physical length (in feet) of the largest pipe - the bigger the number, the lower the pitch of the sound.

For example "Principal 8" is the Principal sound where the longest pipe is 8 feet long. Principal 4 is one octave higher and principal 16 is one octave lower. Therefore if Principal 8 and 4 are selected, every time a note is played, the organ will play two notes, each one octave apart.

Some Aeolus stops have fractions in their numbers; these stops play notes less than one octave from the note normally played - for example Quint 5 1/3 plays 5ths. Also, Aeolus has stops which play several high pitched harmonics to add brightness to the sound. In Aeolus, these harmonic stops are called "Cymbel VI" and "Mixtur".



Real pipe-organs cannot directly control the volume that each pipe produces. To overcome this limitation, organ builders will put some of the pipes in a special room with remotely controlled doors. The doors can be opened and closed to allow more or less volume to escape. The special room is called a "swell box" and the doors are controlled by a pedal at the organ console called a "swell pedal".

Aeolus controls volume through the "Instrum" window, or through the standard MIDI volume controller number 7 (see the MIDI section below).



Large pipe organs often have multiple keyboards, allowing the organist to rapidly switch between the different keyboards to vary the tone and volume of the performance. Aeolus models a large organ which has three keyboards and a pedal board. It is helpful to imagine Aeolus as four organs in one. The four separate organs are called divisions, and are seen in Aeolus main window labelled P, I, II and III.

Division I

The volume of these stops cannot be controlled; in a real pipe-organ, these are the pipes which can be seen. The keyboard would be used when playing loud passages.

division I

Division II

All of these pipes are enclosed in a swell box so volume can be controlled. The keyboard for this division would be the middle board.

division II

Division III

All of these pipes are also in a swell box. In Aeolus, there are two swell boxes modelled, one for Division II and one for Division III - each has a separate volume control and audio settings. This division would be controlled by the top keyboard in the stack.

division III

Division P - Pedal division

Pedal stops generally play the bass, and therefore tend to be the biggest pipes - so big that they are not normally put into a swell box. Due to the limited size of human legs, pedal stops are generally only the lowest two octaves.

division P


To make a really big sound, it is possible to "couple" the divisions together. In Aeolus the couplers are coloured brown. For example, if the I+II coupler is selected, the division I and division II organ stops can be played together from the Division I keyboard.

In single keyboard configurations, it is often best to configure the board as Division I and then use the couplers to introduce the division II and division III sounds.



Just like a real pipe organ, Aeolus also supports presets, which allow stop settings to be stored and rapidly recalled during the performance. With Aeolus you can select presets through the "Recall" button on the main window, or through MIDI keys sent on a separate control channel (see MIDI config below).


MIDI config

In the MIDI configuration window, three things can be configured:

Keyboards - which channel will receive the performance for each division

Divisions - which channels will contain MIDI CC7 (volume) to adjust the volume (swell) for division II and for division III

Control - which channel will receive notes 24 to 33 to recall presets 1 to 10

The Divisions and Control settings are optional.

midi settings

Acoustic parameters of the organ

Through the "Audio" window, Aeolus allows the sound qualities of each division to be separately controlled. This also allows the stereo positioning of each organ to be altered, which makes the performance from Aeolus very realistic.

audio settings

Further reading
The Aeolus home page
Musikun's excellent technical guide and sample performances
The Aeolus wiki
Background information from Wikipedia