Using Reaper

Reaper is a VST Host and Digital Audio Workstation, allowing you to use a variety of low-latency, quality VST instruments, available from other sources. You can also use all kinds of other VST plug-ins from various sources, for effects. You can record both MIDI music, and audio, in the same piece.

Reaper has been used successfully my many people who are blind, and depend on a screen-reader. Software has even been developed for Reaper to aid in that accessibility. Near the end of this article is a link to instructions for using Reaper with KMK, especially tailored for the blind.

Reaper is supported on Windows, MacOS, and Linux.

Importantly (particularly on Windows), it solves the latency problem, and with it, there is no perceptible latency.

Some VST instruments have the full set of General MIDI sounds, up to 16 MIDI channels per track, and will switch instruments by way of MIDI Program-Change messages. Others have their own unique quality sounds, and are not part of the General MIDI instrument set. Most VST instruments do not respond to MIDI program-change messages, but a few of them do.

By chaining the output of one VST instrument with other VST instruments (or effects), you can come up with your own unique instrument sounds.

Though Reaper is primarily designed for MIDI recording, it also works well for live-performance.

As with any full-featured software package, there are a lot of features to configure and learn. Fortunately, Reaper has done a good job of supplying video tutorials.

Here is a sample improvisation using the KMK with Reaper, using the Numa Player, which is a very good VST instrument, available at no cost. You can listen to the sample by activating the link below:

Sample Improvisation With The Numa Player, on Reaper

On Windows

At a minimum, to use Reaper with the KeyMusician Keyboard, you will have to first install an ASIO device driver for your sound-card (see Installing ASIO4ALL), though maybe not on Windows 11. Also, you will either have to connect a hardware MIDI interface (see Connecting A Hardware MIDI Interface), or install a software MIDI interface (see Installing LoopBe1).

On MacOS

to use Reaper with the KeyMusician Keyboard, you need the internal MIDI interfaces turned on (if you haven't done it already). You can learn how to do that, by activating the link below:

Turning-On The MIDI Interfaces

On Linux

You can supposedly convert VST instruments to a form that can be used on Linux. I attempted that, but did not succeed. That process is something for a future KeyMusician Newsletter article to delve into.

Reaper supplies one VST instrument in the Linux install (called ReaSynth). Reaper should be able to use LV2 instrument plugins, and there are a lot of them installed by the ‘Extras’ dependencies of the KMK. Unfortunately, at the time of this writing, Reaper does not display their instrument control panels, and few of them will run without doing things with the instrument control panel.

In particular, the FluidSynth Calf-Plugin needs the sountfont it uses to be specified by the control panel (which Reaper doesn’t display). And with no soundfont, there’s no sound... Hopefully, Reaper will fix this shortcoming in the future.

To run Reaper on Linux, you need to first start JACK (qjackctl), and also a2jmidi (ALSA to JACK MIDI).

Setting-Up Reaper

When you first run Reaper, it asks you to specify your audio output device, and you should do that at that time.

But you also need to specify which of the MIDI devices on your system, Reaper is allowed to use.

You can access Reaper’s preferences by accessing its menu. On MacOS, you access Reaper...Preferences. On Windows and Linux, you access Options...Preferences.

Here is a screenshot of referencing Reaper’s preferences on MacOS:

Picture of the Reaper window, with the Reaper Preferences window in the foreground.
In these preferences, it is “IAC Driver – Bus 1” on MacOS. On Windows, it would be one of the two LoopBe ports. On Linux, it would be either MIDI Through Port 0, or A2J MIDI.

You double-click the port’s line in the list to enable it. Enable it for control messages as well as input. I usually leave one of the internal MIDI ports for use by the MIDI Player/Recorder, so I don’t enable both of them in Reaper, leaving one of them available.

Usually you don’t use the MIDI output devices, but if you have a need in some special case, you enable the output ports (in the lower right pane) in the same manner.

Initially (the first time you run Reaper, or when you select the “New Project” toolbar item, or menu entry), the first thing you do, in this new state, is to insert a new track.

I like to create the tracks in the order of the MIDI channel each track uses, but be aware that a single track can make use of all 16 MIDI channels.

You insert a new track by selecting (in the Track menu), “insert virtual instrument on new track”. When you do that, a window appears allowing you to select the virtual instrument, similar to the following screenshot done on MacOS:

Picture of the Reaper window, with the Insert Virtual Instrument on New Track window in the foreground.
Select the instrument you want (I selected the last one in the list), and activate the “Add” button.

When you do that, the VST instrument’s control panel appears, here for the Numa Player, as in the following screenshot:

Picture of the Numa Player control panel, set up for use by the KMK chords pane.
With the Numa Player, you can have up to 4 different instrument sounds playing simultaneously. The power-on icon (a semi-circle with a short vertical line on top) selects whether it is turned-on or not. Click on it to turn it on, or off.

To the left of the power-on icon, is a rectangle with a horizontal line inside it. Click on its horizontal line, and drag it up or down to control the relative volume of a sound that’s enabled (turned-on).

For each of the four sounds in the left pane, there’s a drop-list sort of area. Click on the drop-list graphic, and you can select the sound used from any of the several sounds available.

In the screenshot above, I’m using a “Model D 1983” piano, and in the bottom sound (Strings & Pads) I’m using “StringsEnsemble”.

Both of these instrument sounds together, give me a crisp piano sound, along with a sustained string orchestra sound, which is perfect for the chords sound.

You can click on the keyboard diagram at the bottom of the window to play notes, and evaluate the sound.

When you’re done, close the window. The newly created instrument and track will appear in Reaper.

Repeat this process for as many tracks as you need. If each track uses a single MIDI channel, with the KMK, you probably want one track for the melody, and one track for the chords.

Here’s a screenshot of the instrument control panel I used for the melody instrument:

Picture of the Numa Player control panel, set up for the KMK melody performance-panes.
For the melody sound, I used all four possible sounds, using a piano, an electric piano, a harpsichord, and a string ensemble.

Here’s a screenshot of the tracks area of the Reaper window (at the left side of the Reaper window):

Picture of the instrument area of its tracks area, with two Numa Player instruments in it, labeled Chords, and Melody.
Notice that there are two instruments. Instead of just “Numa Player” appearing as the name of each instrument, I have named them: “Numa Player - Chords”, and “Numa Player - Melody”. You re-name them by double-clicking in the place where the instrument name appears.

The next thing to do in Reaper, is to assign the proper MIDI channel to each track – one for the chords, and the other for the melody.

In an instrument track, just below the instrument name, is an area looking like a drop-list, labled “IN FX”, showing the MIDI device and MIDI channels used for input.

Click on that drop-list area for the chords instrument, and in the popup menu that appears, choose “Input MIDI”, “All MIDI Inputs”, and “Channel 1” for the chords instrument.

Click on that drop-list area for the melody instrument, and in the popup menu that appears, choose “Input MIDI”, “All MIDI Inputs”, and “Channel 2” for the melody instrument.

After doing that, the two instruments should look very much like the screenshot above. Notice that the top instrument uses MIDI channel 1, and the bottom (selected) instrument, uses MIDI channel 2.

If you ever want to call-up the control panel for one of the instruments, simply single-left-click on the little square labeled “FX”, to the right of the instrument name of the instrument you want to change.

At this point, your Reaper project is ready to use, and you should save it. In Reaper’s “File” menu, select “Save project as...”, and choose a descriptive file name you will remember.

Setting Up The KMK For Reaper

I supplied a KMK configuration file you can use with a project such this. It has a Chords pane using MIDI channel 1, and all of the melody panes, using MIDI channel 2. It’s somewhat unique, in that each performance pane (including the Drums pane and the Chords pane) uses a different key-signature, so you can select any of the possible key-signatures just by pressing a function-key. You can download that configuration file by right-clicking on the link below:

All Key-Signatures Config

Choose “Save Link As” (or whatever similar thing your browser offers in the popup menu that appears), to download. You need to put it in your “KeyMusician-Keyboard” folder to have it appear in the menu of configuration files, the next time you run the KMK.

Fire up the KeyMusician Keyboard application, and when it’s ready to play, switch to the “F1 Help/Setup” pane by pressing F1.

In the “Configuration File” (setup file) drop-list, choose the “Numa-AllKeySigs.kmk” configuration file (the one you just downloaded). For that matter, you can use any configuration file. Just make sure it uses MIDI channel 1 for the chords, and MIDI channel 2 for all the melody panes.

Make sure the “MIDI Output To” drop-list in the KMK F1 pane, is set to what you need for your system (the first LoopBe port for Windows, the first IAC MIDI port for MacOS, or MIDI Through Port 0 on Linux).

Playing Reaper on the KMK

It should be ready now. Switch to one of the melody panes (such as F2), and start playing.

Here’s a screenshot of the KMK windows and the Reaper window side-by-side on MacOS, using the configuration I provided:

Picture of a Mac OS screen, with the KMK windows on the left, and the Reaper window on the right.
Notice in the picture above, the instrument drop box (set to “32-Grand Piano & Strings” ) does not affect the VST instrument used here. The Numa Player, like many VST instruments, ignores MIDI Program-Change or Bank-Change messages.

Accessibility for the Blind

Reaper has been used successfully my many people who are blind, and depend on a screen-reader. Software has even been developed for Reaper to aid in that accessibility.

Activate the following link, to read instructions for using Reaper, especially tailored for people who are blind:

Using KMK With Reaper While Blind

The instructions for the blind, at the URL above, were written by Jackie McBride, who is a minister's wife & grandmom, a web hosting provider, a cybersecurity and accessibility advocate, as well as a musician-wannabe. You can check her sites at, and You can contact her at

Where To Get Reaper

You can get Reaper at the following web-address:

Reaper Digital-Audio-Workstation

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