Image muse2

Contents

What is this?

You are, if you have printed this document, holding in your hand the written documentation for the audio and midi sequencer MusE version 2.
http://www.muse-sequencer.org is MusE's home on the internet where everything MusE releated should be possible to find, software, this documentation, forums, mailing lists, bug reporting, FAQs. If you have this document but not the software head on over there to find what it's all about.

User's manual

Introduction

A brief history of computer audio and MusE

To quickly summarize over a decades open source development: in 1999 Werner Schweer released the first version of MusE, muse-0.0.1.tar.gz, in it's first few releases (actually not few, Werner relentlessly churned out new releases) MusE was only a midi sequencer. The target was to create a fully fledged midi sequencer for the Linux operating system. Over the years audio was added among with other things implemented and sometimes abandoned. Today MusE is a stable and feature rich music creation environment which strives to encompass most of the music recording process, creation, editing, mastering.

Definitions

CTRL refers to the control key on the keyboard, e.g. CTRL+C means to press and hold the control key while pressing the c key. Make sure you know where you have it so you won't accidentally lose control (bad jokes are the best jokes, so say we all!).
SHIFT refers to the shift key on the keyboard, see above for usage
ALT refers to the alt key on the keyboard, see above for usage
$> is used as a generic definition for a terminal prompt. When the manual lists a command that shall be typed, the prompt is not part of the command.
Keys are always referred to in bold uppercase, e.g. A. For instance SHIFT+A for the key a pressed together with the shift key.
Sometimes terminal examples are written tabbed in with a fixed font to visualize more closely what something looks like on the screen. E.g.
$> muse2

Getting up and running for impatient people

Install MusE from the repository of your chosen distribution. To get decent performance start http://jackaudio.org/Jack with the following command in a terminal:
$> jackd -d alsa -d hw:0 -p 256
Or, if you prefer, use the launcher utility http://qjackctl.sourceforge.net/QJackCtl to get some help starting Jack. After this, start MusE from the menu or fire up another terminal and type

muse2.
If this didn't work out read on for the slightly more complete route for getting things started.

Getting up and running

Installation from binaries

There are several ways to install MusE depending on your situation. The most convenient way is to install a prepackaged version from your chosen distribution. The drawback of this is that it may not be the most recent version, though often there is a more recent package from a private packager.

Installation from source

Building MusE from source is not hard, there are a number of prerequistes that must be met but the actual building should be painless (ha, famous last words).
Please follow the README in the source package and/or read the instructions on the homepage: http://muse-sequencer.org/index.php/Installation

Hardware

MusE on the Linux platform supports midi through ALSA and Jack-midi and audio through Jack. For information on what hardware is supported there are some convenient places to check: Also, as is often a very good approach for Linux and open source, the various forums available on the internet often contain good information. Chances are someone has already tried your configuration and/or had your specific problem and the solution is already written down.

Launching

After installation the binary muse2 is installed on the computer. If MusE was installed from a distribution repository the binary may have a different name depending on the distribution policies. Most distributions do however install a menu entry so MusE should be conveniently available from there.

Audio preconditions

In the standard case MusE expects to find and connect to the Jack audio server http://jackaudio.org. Make sure jack is installed (if MusE was installed with a distribution-package Jack will very likely already be installed) For Jack to run with best performance your system should be sufficiently tuned to allow it to run with realtime capabilities. The realtime configuration is configuration of the operating system and roughly consists of two parts.
  1. By default on most distros only the superuser lets applications setup realtime capabilities. Please see the APPENDIX for setting up realtime
  2. Maximizing performance. A standard linux installation may not able to reach the performance required by a power user. This requires exchanging the linux kernel for a so called lowlatency kernel, this is also covered by the realtime APPENDIX.

Running MusE

Find MusE in the menu or open a terminal and enter muse2.

$> muse2
A splash screen should pop up followed by the main application window and you are off!
If an error like the screenshot below pops up the Jack audio server is either not running or started as a different user than what you are trying to start MusE as.

Figure 2.1: Jack server missing
Image no_audio

Midi only

MusE can be started in Midi-only mode where MusE does not have any external dependencies apart from ALSA midi. In this case start MusE from a terminal: $> muse2 -a

ALSA midi with Jack

If Jack is running, by default MusE will not use ALSA devices, preferring Jack midi instead. To force ALSA devices to be used as well as Jack midi, start MusE with the -A option: $> muse2 -A

Beginners tutorial

To get a quick grip of what MusE can achieve please follow this beginners tutorial.

Midi Setup

First off, fire up MusE as was described in the previous chapter, making sure that the jack audio server is started with sufficient configuration to allow for audio output without breakup. Also make sure your system can make sound.

Soft synth test

With MusE up and running right click in the Track-pane (see Fig. 2.8) and select Add Synth > MESS > vam soft synth. A Soft Synth track called vam-0 should appear as well as a separate GUI for the synthesizer.

Now right click once more in the Track-pane and select Add Midi Track. Another track appears called Track 1, and its track list Port column should show it is bound to the synth that was just created vam-0. If it is not, click on the Track 1 Port column to open a drop-down list of available devices and choose vam-0.

r0.05 Image arrow_tool
Now select the drawing tool icon from the toolbar, alternatively press the shortcut key D. Move the mouse over to the arranger canvas as referenced in Fig. 2.8 and point at the midi track, the mouse should have changed to a small pencil. Draw a Part along the midi track using the mouse. For this exercise it is not important where or how large the drawn Part is. When you are done double click on the drawn part. This will open up the Piano Roll editor. To the left of the Piano Roll there are piano keys in a vertical line, try clicking on the keys in this virtual keyboard each click should be rewarded with a synth sound (maybe of questionable quality, a sound nevertheless)
Figure 2.2: vam synthesizer
Image vam_synth

Missing sound

If you got sound from the previous exercise you can carry on to the next, or keep reading for further enlightenment in case you come upon trouble later on. If there is no sound we need to do some fault hunting. First off, click on Arranger window once more and select the vam-0 track in the track-pane.
Figure 2.3: Midi editor view
Image main_window_with_midi_editor_vam
Now bring back Piano Roll window and align the windows so you can see the piano keys as well as the Meter on the Mixer Strip (see the 5 Function by function chapter for more information on these windows). The result should be something like the following:

When pressing one of the keys on virtual Keyboard the Meter on the Mixer Strip should light up in green to visualize that the Synth is making sound, if it is not try to trace back your steps and and see if you did anything differently than described. Now, if the Meter lights up but there is still no sound we need to check the routing between the tracks. Click on the Arranger window again and select the Out 1 track, this is the predefined output which MusE by default loads at startup, at the bottom of Mixer Strip there are two buttons looking like tele- jacks, these bring up the inputs and outputs of the track, click on the right one, the output and make sure that it is connected to some valid outputs on your system.

r0.25 Image output_routing
Click on the outputs to select them, if you did changes here go back and try clicking on the Piano Roll keyboard again, hopefully it helped. If there still are problems make sure your system actually can make sound through Jack, this is however getting outside the scope of this manual.

This might be the time to bring up the concept of community support. Open source software could never be what it is without the support given by individuals on forums and mailinglists, if the information given in this document is not enough, try googling your problem and/or get in touch with one of the online forums for MusE or Linux audio in general. See some pointers in the Support chapter.

Recording Midi

TBD

Recording Audio

At this point we'll make a a slight detour into full on audio recording. Getting audio out of MusE has already been covered in the previous chapters so we will concentrate on the additional steps needed to record onto an audio track.

When MusE is first fired up, the output track has already been created (more about this in the chapter about templates), to proceed with audio recording we need to add two additional tracks, a wave track and an input track.
When MusE is first started right click in an empty space on the track view
Figure 2.4: Add track
Image main_window_add_track
and select Add Audio Input. Right click again and also select Add Wave Track. Two additional tracks are now visible in the Arranger, "Input 1" and "Track 1", bring up the mixer with F10 and you should see the following configuration.
Figure 2.5: Mixer with one input
Image mixer_with_one_input

Note the buttons on each mixer strip. hover over them to see their functionality. For more information on all the buttons see coming chapters about the mixer. For now lets just do what we must.
1. click on the stereo symbol over the slider to change the input to a mono track.
2. do the same for the wave track (optional)
3. click on the Mute (gray speaker) icon on the input track to unmute it.
4. click on the input routing button (see the tooltip, it looks like a tele plug) on the input track and select an appropriate connection from your system.
5. click on the output routing button on the input track and select Track 1

Already after the meter on the input track should be able to display that there is incoming sound from your sound source. If there actually is sound coming from your sound source, that is.
We are now nearly ready to start recording. First we need to select a location to store the files. MusE does not use a centralized storage of soundfiles but uses the path of the song-file (extension .med) as guidance as to where the audio files should be placed. Now as it happens MusE will prohibit us from starting a recording until the songfile has been stored. So lets take advantage of this behaviour and just go ahead and try to record. Let's get started.
In the mixer click on the red record dot on the Audio Track to arm it for recording (or enable if you will). Now when there is audio coming into the input it will also show up on the Audio Track. Also note that all the input and output routing buttons on the tracks now have the same gray color, this means that all of the tracks have a proper connection.
Figure 2.6: Mixer buttons
Image mixer_with_one_input_buttons

All fine and dandy. Now bring up the arranger window and find the round, red on white record button and click on it. This is your queue to MusE to prepare for recording. However since we have not saved our song we are presented with a dialog to do just that.
Figure 2.7: Save song
Image project_my_first_song
Note the check box for creating a project folder, when working with audio this is very much recommended or you may soon loose track of what audio files belong to which song.
Finally we are ready to start recording! The process is completed by clicking on the Play button in the Arranger. If all went well MusE then starts to record a wave file from the Input Track placed in your song directory.
When you wish to stop recording press Stop in the Arranger, now the resulting waveform should be visible in the Arranger. After rewinding the Play position and pressing Play again the resulting sound should be audible through the connected output.

Basic overview

In this section we will make a step by step walk-through of all the different editors, their purpose and what functions they support.

Main/Arranger

Figure 2.8: MusE main window
Image main_window_annotated
Above is the main window of MusE, the Arranger, this is what greets you when launching MusE. The Arranger consists of two main parts, the Track-pane and the Arranger canvas. The Track-pane lists all currently visible tracks and the Arranger canvas contains all Parts of the composition. The screenshot above shows an empty project. Below is MusE with a song in progress, turns out it wasn't a very good song, but for our purposes it is fine. In the below screenshot there are a lot of tracks visible in the Track-pane, each have an icon which indicate it's type, wave-track, input, output etcetera, more about that later. In the Arranger canvas a number of parts are visible, the ones in yellow are in this composition wave files, the multicolored line are different Parts of a drum track.

Figure 2.9: MusE main window with arrangement
Image main_window_with_arrangement


Mixer

Choosing View > Mixer A or B from the menu in the main window will bring up the mixer as viewed below. The mixer will open with all options enabled, showing channel strips for all tracks in the current setup, depending on how far you have gotten this view may become very large, at which point it may be a good idea to limit what is viewed in the Mixer. From the view menu all the different kinds of tracks can be toggled on/off from the mixer. Some may find it a good idea to use the two mixers A and B setup with different setup and store this in your song template(s), more about this in the Song Template section. It can be argued that everything in MusE is a track analogous to the Unix idiom that everything is a file. The types of tracks visible in the mixer (and track-pane) are:
r0.5 Image mixer

There is also a Midi Track variation called Drum Track, they are however not distinguishable from Midi Tracks in the Mixer. Also the strips for midi tracks are different in the Mixer than in the Track-pane view.

Tracks and parts

MusE arranges your music in tracks and parts. The following section shall provide you an overview of how things are done with MusE. If you are or were a Cubase or Cakewalk user, you will feel familiar with this.

Tracks

There are two general classes of tracks: MIDI tracks and audio tracks. MIDI tracks (and drum tracks which are internally MIDI tracks) can hold note data. The Wave track is a type of audio track which holds wave data. There are also several other kinds of audio tracks.

MIDI tracks

MIDI and drum tracks hold MIDI event data. They don't differ much, except that drum tracks offer a special editor which is more suitable for drum editing.

Wave tracks

They hold audio data which can be just played back or be piped through effect plugin chains. They offer automation for these plugins.

Audio input tracks

These provide the path for your audio data from outside into your project. Set up the physical audio inputs you want to connect your audio input track with, and then route the input tracks to various other tracks such as wave tracks.

Audio output tracks

These provide the path for your project's audio data to outside. Set up the physical audio outputs you want to connect your audio out track with, and then route various other tracks, such as wave tracks, to the output tracks.

Audio group tracks

Group tracks are like busses, where you can route other tracks to them, then route the groups to other tracks. Since group tracks have all the features of other audio tracks, like volume and pan, they provide a convenient common routing point where you have control of the sound before it is passed to other tracks.


Audio aux tracks

These provide a more convenient way to mix several audio tracks together. With each audio aux track added, other audio tracks will gain a common send knob for adjusting the level sent to the aux track. This can be more convenient than using several group tracks.

Synthesizer tracks

This type of track is a software synthesizer which MIDI and drum tracks can be assigned to.

Creation

You can create a track by either right-clicking in the arranger's track list and then adding the desired track, or via the edit menu.

Attributes

Tracks have several attributes:
Mute:
If you click on the Mute field (denoted with a "M" column header), the track gets muted and stops producing sound.
Solo:
The solo button ("S" column header) singles out a track for listening. It mutes some other tracks but may phantom solo others. For more info see the section on soloing: 2.5 and phantom soloing: 2.5.1
Record:
The R column "arms" your track for recording. When you rec-arm your song and have no tracks rec-armed, you won't be able to record anything. See also the config option "move rec-arm with selection".
Track name:
Double-click to edit the track name.
Port:
For MIDI tracks, this lets you select the MIDI port to which the events should be routed. This can be your physical synthesizer or a software synthesizer. For soft synths, this is the port the synth is associated to. For other track types, this is disabled.
Channel:
For MIDI tracks, this is the MIDI channel the output is sent to. For any kind of audio tracks, this is the number of channels (mono, stereo).
Automation:
For audio tracks, this lets you set up the automation display in the arranger. (See automation 2.7.1). Clicking this will provide you with a popup menu with lots of submenus. Clicking on a submenu will select or unselect it showing or hiding the automation parameter as a graph overlaid on top of the track.
The submenus let you select the color you want to associate with the automation parameter. There you can also assign midi controllers to the parameters, a dialog is shown where you can manually choose the midi controller, with a learn button to 'listen for' and automatically recognize any midi controller operated by you.

Clef:
For MIDI tracks, you can specify a clef here. This only affects the score editor.

The trackinfo side bar

In the arranger and the part editors, you'll have a trackinfo sidebar on the left side. You can set up track-type specific things there.


MIDI trackinfo sidebar

The MIDI trackinfo sidebar lets you change program, volume, pan and more. This sidebar can also be viewed at the left of the pianoroll editor.
Old style drum tracks:
These are MIDI tracks as well, but with a few differences. They allow you to map certain drum sounds with different input notes, and you can change the output settings of a certain "drum instrument" without having to alter each single event.

However, they have certain limitations: They only can handle 128 sounds (even if you have more synthes), they aren't really compatible with MIDI tracks (you can interchange parts between them, but if you touched the drum list, you'll get unexpected results), you can't set a program for the used channel and more.

New style drum tracks

Because of these limitations, we introduced the new-style drum tracks. They're not fully compatible with the old drum tracks, so the old are still retained. Under "Global Settings", "GUI settings", you can set up whether you prefer the old or new.

They are handled exactly like plain MIDI tracks (staying compatible with them), and offer all of the functionality, though in a different way. They allow you to re-order the drum map efficiently, you can open parts from multiple drum tracks in one drum editor (MusE will separate the sounds from different tracks according to your settings, see the "Window Config" menu), and you can set programs as with normal MIDI tracks.

MIDI trackinfo controls:
Output port:
This drop-down list selects the midi port to send midi output from this track.
Output channel:
This box selects the midi channel to be used on the output port.
Input and output routing:
Selects midi ports and channels to receive midi from, and soloing paths. (See Routes 2.4).
Midi through:
This button selects whether midi input is passed through to the selected output port.
Depending on your midi devices and settings, there are cases when this should be off such as using the same port and channel for input and output (otherwise a double-note echo will be heard), and cases when it must be on such as when using a synthesizer track as output device.
Input detect indicator:
Blinks when midi activity is detected on the selected midi channels on the selected midi input ports.
Transpose:
This transposes midi input notes up or down in pitch. This is very useful if your midi keyboard hasn't enough keys or the selected output device plays an octave too low or high, and you would like to shift the octave of the incoming notes to compensate.
Delay:
Adjusts the delay of the notes.
Length:
Adjusts the length of the notes.
Velocity:
Adjusts the velocity of incoming notes. Use it to compensate for a too-loud or too-soft keyboard.
Compression:
Adjusts the compression of incoming note velocities. Use it to make soft incoming notes louder, and loud notes not so loud.
Instrument:
Selects the midi instrument patch to be used by the selected output port. This is equivalent of dialing the patch in the bank and program boxes, except it displays a more friendly patch name as defined by the selected output port's midi instrument. See instruments, or port configuration 2.8.1
H-Bank:
Selects the high bank number of the current patch.
L-Bank:
Selects the low bank number of the current patch.
Prog:
Selects the program number of the current patch.
Volume:
Adjusts the midi volume controller.
Pan:
Adjusts the midi pan controller.
The buttons beside the Prog, Volume, and Pan boxes store the value, at the current transport position, for midi automation. (See automation 2.7.1).

Note that the 'Prog' button stores H-Bank and L-Bank along with 'Prog' value, so there are no H-Bank and L-Bank buttons.

The 'All' button simply stores all three Program (and banks), Volume, and Pan values at once.

Tip: If the Song Type is GM, GS, or XG, you may need to store desired values at transport position zero, otherwise your adjustments may be overriden by the instrument when the transport is moved back to position zero. If this behaviour is undesired, you can set the Song Type to 'NO' meaning no song type.

Audio trackinfo sidebar

Unlike the midi trackinfo sidebar, the audio trackinfo side bar is nothing more than an embedded audio mixer strip, the exact same strip as found in the mixers. (See mixer 2.2.2).
Effects rack:
On the top of the audio trackinfo sidebar, there is an effects rack which allows you to apply various plugins on the audio. For more information on this, refer to 2.6.1.

Parts

Within MIDI, drum and wave tracks, you can create parts. Parts are chunks of coherent notes or wave data which can be moved around, copied, cloned and deleted independent from other parts.

Parts are created by selecting the pencil tool and then drawing onto the right part area in the arranger. You can move them with the arrow tool, delete them using the DEL key, and a right-click opens a popup menu. This menu allows you even more stuff, such as setting the part's color, saving the part to disk etc.. You can use CTRL+C and CTRL+V for copying and pasting parts. CTRL+B pastes the part as a clone. Pressing SHIFT additionally provides you a dialog which allows you to paste the part multiple times and set more stuff.

You can also copy parts with the mouse by moving the part with the mouse while holding down the CTRL key.


Routes

Routes are how tracks are connected together and to the outside world. (They are also how Jack midi ports connect to the outside world. See midi port configuration 2.8.1). Each track strip has two buttons whose icons look like plugs. One button is for input routing and the other is for output routing. Clicking on these buttons will pop up a menu of available input or output routes that you can connect to. Most audio tracks list other tracks to connect to, but audio input and output tracks are special: Audio input track input routing menus list available Jack audio input ports. Conversely audio output track output routing menus list available Jack audio output ports.

r0.25 Image output_routing

Meanwhile MIDI and drum tracks allow you to route available MIDI ports and channels to the track using a handy popup matrix.

r0.25 Image midi_routing_matrix


Anti circular routing

Any routing menu item which would cause a circular routing condition is grayed out. Find out why the condition would exist by examining routing paths involved and correct the situation if required.

Also, you cannot use a track's aux sends if the track has an input route path from ANY Aux Track. (See aux tracks 2.3.1). Aux send knobs and labels are disabled in that case.


Soloing chain routes

Soloing chains (see solo chains 2.5.2) are really just routes like any other. The available solo chaining paths are displayed in the routing popup menus.


Track soloing

Soloing allows you to single out a track for listening while muting others, without you having to mute the other tracks. (See soloing track attribute 2.3.1).


Phantom soloing

In order to solo a track and mute others so that it is heard, MusE employs 'phantom' soloing: When a track is soloed, MusE automatically solos all tracks routed to and from this track. (See routes 2.4). A phantom soloed track is indicated by a black square in the track pane solo column. (See track attributes 2.3.1).

Figure 2.10: Soloing, with phantom soloing
Image soloing_window


Soloing chains

When an audio output track sends audio to some external entity, such as an external running application, and audio from the external entity is fed back into a MusE audio input track, solo chains allow you to solo the input or output, and MusE will complete the path automatically soloing the other, and all paths that came before or after it.

Solo chains also work with MIDI tracks chained to audio inputs: When a MIDI track drives some MIDI device whose audio is fed into MusE, solo chains allow the entire chain to be soloed.

Solo chains are accessed via routing menus. (See solo chain routes 2.4.2).


Plugins

Plugins are small add-ons which can process a track's data.

MIDI plugins operate on midi and drum tracks, and are found in the Midi menu.

Audio plugins can be applied to any track handling audio (that is, inputs, outputs, wave tracks, synth tracks). The effects rack section describes this. (See effects rack 2.6.1).


The audio effects rack

All audio track types (Input, Output, Group, Wave, Synth, and Aux) have an effects rack into which audio plugins can be inserted in a chain. Currently each rack can accomodate up to four plugins.

MusE currently supports LADSPA plugins and DSSI synth and effects plugins.

Plugins can be added by double-clicking on an entry in the effect rack in the track info pane (which is shown at the left side of the arranger when the according track is selected). Right-clicking the rack items offers a self-explanatory popup menu.

All plugin controls can be automated. (See audio automation 2.7.1).

One must carefully consider how many audio inputs and outputs a plugin has, and how may channels the particular audio track has (1 mono or 2 stereo), and how MusE uses the plugins in the rack.

Learn more about this in the appendix Understanding the Effects Rack: 3


Audio plugin Graphical User Interfaces (GUIs)

Once a plugin is added, you need a way to manipulate its controls, which affect its behaviour and operate on the sound.

MusE can show a generic GUI which contains all of the plugin's controls arranged in a rather plain generic fashion.

Some plugins may also have a native GUI which looks much better (it was specifically designed for the plugin).

Both GUI types are opened from the effects rack right-click popup menu.


Automation

Automation is the ability to record (or construct) and playback exact sequences of control movements.

MIDI and audio automation are each currently uniquely different, but share some similarities.


Audio automation

Almost all graphical audio controls in MusE can be automated.

This includes an audio track's volume and pan, and the controls of any plugins in the effects rack, and if the track is a synthesizer track, all of the synth's controls.

Each control has a manual adjustment value. This value is shown when there is no automation data at all, or automation has been disabled.

For plugin and synth controls, it is usually more desirable to manipulate automation with the generic plugin GUIs, because MusE has full control over their behaviour. (See plugin GUIs 2.6.1).

There are a few ways to enter audio automation data:

Audio automation modes

Each audio track strip has an automation mode button at the bottom. There are four automation modes:
OFF:
Disables all automation, uses manual value always.
READ:
Automation data is applied to controls. If any automation data exists, the manual value is overridden and has no effect.
TOUCH:
Allows you to alter a control at any time, while transport is stopped or rolling, If rolling, when the control is released it returns to reading from automation data.
WRITE:
Allows to adjust an initial value before rolling the transport. While rolling, when the control is released it does not return to reading from automation data.
Here is a screenshot of automation WRITE mode, and some automation data, with the track pane automation popup menu showing (see track automation 2.3.1):
Figure 2.11: Audio automation graphs
Image main_window_with_automation

Midi automation

MIDI automation is a slightly different concept: Unlike audio automation, currently there is no automation 'mode' and it doesn't record graphical control movements. Data is viewed from within the pianoroll and drum editors, by clicking on the 'Ctrl' button on those canvases.

Similar to audio controls, each midi control has a manual adjustment value. This value is overridden when there is midi automation data.

There are a few ways to enter MIDI automation data:

Here is a screen shot of a midi track, containing a midi part which has been opened with the pianoroll editor and automation data showing.

The 'Ctrl' popup menu (bottom left) shows available midi controllers and the green dot indicates there is some data.

Figure 2.12: MIDI automation graphs
Image main_window_with_midi_automation

Configuration

MIDI ports

MIDI ports provide an abstraction layer for your MIDI hardware and synthesizers (which can be both software and hardware synthesizers), and other MIDI applications. Port are numbered. In order to produce sound, each MIDI track is assigned to exactly one MIDI port, to which the MIDI events are then sent.

The advantage of this abstraction layer is that if your system changes, for example you change MIDI hardware, then you need only modify the ports instead of all the tracks using those ports. This is similar to the audio input and output track abstraction to the outside world.

MIDI port configuration

In the midi/softsynth configuration menu, you must map the port numbers to the actual devices (by selecting ALSA or jack midi ports, or synth plugins).

Try left-clicking on the "Ports" column of some MIDI track. If you use a soft synth, right-clicking the Ports column of the synth or any track using the synth lets you launch the synth's GUI.

Figure 2.13: Midi configuration window
Image midi_config_window

Columns in the MIDI configuration ports list:

GUI:
For synthesizer devices, indicates if a gui is available and if it is showing. Click to show.
I:
If present, the port can accept MIDI input. Click to enable or disable it.
O:
If present, the port can send MIDI output. Click to enable or disable it.
Instrument:
Selects the instrument to be used when MIDI is played through the port.
Device name:
Selects or creates a MIDI device assigned to the port. These can be Jack MIDI devices or ALSA MIDI devices (if ALSA is enabled), or soft synthesizers. Jack MIDI devices are created by selecting Create Jack Device from the Device name drop-down menu. Jack MIDI devices can be renamed as you wish by clicking the device name. Soft synthesizers are created by clicking in the soft synthesizer list and then Add Instance. Or you can simply create a new synthesizer track from the arranger track list, or even the mixer menus.
In and Out routes:
These are for Jack MIDI devices, they are the routes to and from available Jack MIDI ports. Jack may provide different alias names for these ports, you can select which alias is shown.
Default in channels:
Auto-connect these port channels to new midi or drum tracks.
Default out channel:
Auto-connect new midi or drum tracks to this channel on the port.
State:
Indicates the state of the port including any errors opening it.

Global settings

Audio settings

Minimum control period

Plugins can usually process an arbitrarily small (or large) amount of samples. If some plugin control value changes continously, to provide ideal listening experience, MusE would need to call the plugin 44100 times a second, asking for one single value at a time. With the minimum control period setting, the user can force MusE to ask the plugin for at least N values. Setting this value to 64 would in this situation make MusE call the plugin $689=\frac{44100}{64})$ times a second, asking for 64 values at a time. While doing this will reduce accuracy of control changes, it may also reduce CPU usage, because calling the plugin more often, requesting smaller chunks, is more expensive than calling it seldomly, requesting larger chunks.
Recommendation
If you have no performance problems, or if you want to do the final downmix of your project, set this to a low value. If you're experiencing performance problems, increasing this value might help.


Appendix

Understanding the effects rack

One must carefully consider how many audio inputs and outputs a plugin has, and how may channels the particular audio track has (1 mono or 2 stereo), and how MusE uses the plugins in the rack.

MusE will try to internally create as many independent copies (instances) of a plugin as necessary, to satisfy the number of channels in the audio track. Basically it divides the number of track channels by the number of plugin audio inputs or outputs to determine how many copies to make. First it examines the number of plugin audio outputs, and if there are none, it will examine the number of audio inputs, and if there are none, it will simply use just one plugin copy.

For mono tracks with plugins having more than one audio input or output, MusE uses the first input or output and ignores the rest.

For stereo tracks:

plugin inputs outputs copies track in route channels track out route channels
0 0 1 0 0
0 1 2 0 2
0 >=2 1 0 2
1 0 2 2 0
1 1 2 2 2
1 >=2 1 1 (L only) 2
>=2 0 1 2 0
>=2 1 2 2 2
>=2 >=2 1 2 2

Notice that on a stereo track with a plugin having one audio input and two audio outputs, only the first track input route channel is used (left only).

These same rules apply to inter-plugin audio when more than one plugin is in the rack chain. Extra audio outputs of one plugin may be ignored by the next plugin if not used.

Currently specialized plugins with many inputs and/or outputs are not really useful in MusE.

Nor are so-called 'realtime' control plugins which use audio inputs and outputs for control signals.

Loud noise alert! Beware of using such plugins in an audio effects rack.

Example: Consider a stereo Audio Input track with these effect rack LADSPA plugins:

The Comb Splitter has one audio input and two audio outputs. The Stereo Echo has two audio inputs and two audio outputs.

The stereo Audio Input track will therefore ignore its second input route connection. It will process the left input only, separating it into stereo with the Comb Splitter, passing the split stereo signal into the Stereo Echo, finally producing stereo output available at the Audio Input track's output routes.

One improvement would be not creating unused redundant plugin copies between plugins in stereo tracks. For example, for a plugin having one audio input and one audio output, feeding a plugin having one audio input and two audio outputs, the extra copy of the first plugin is redundant and not required, but currently it is created anyway.