Exercises

This page is a work in progress. Any help appreciated.

Preface

This tutorial explains how to do the exercises found in the book "The Complete DX7" by Howard Massey on MiniDexed. The book provides a through introduction into how Frequency Modulation (FM) synthesis works and helps one to understand how instruments like the DX7 and MiniDexed use FM to produce sounds.

Prerequisites

While for playing it is desirable to have multiple Tone Generator (TG) instances and sound effects, this is not desirable for learning how Frequency Modulation (FM) synthesis works. hence, all of the exercises use only one Tone Generator (TG) instance, which equals to one DX7 instrument. All exercises also assume no effects to be present, like on the DX7 instrument. To perform any of the exercises, prepare MiniDexed like this:

TODO: Provide downloadable performance and voice files for this, so that new users don't have to do the initial setup themselves

• Disable all effects (by setting them to Off)
• Disable all TGs except TG1 (by setting Channel to Off)
• Set panning to center for TG1
• Set Detune to 0
• Load a patch that contains E.PIANO 1 and INIT_VOICE and a few other characteristic ones

Conventions

These conventions are used to make the instructions more readable:

• Menu items are bold
• Parameter values are italic

Chapter 1: Basic Audio Theory

The basic theory applies today just like it did 4 deacades ago.

Chapter 2: The Menu

Unlike the DX7 instrument 4 deacades ago, MiniDexed uses a menu strucutre like found on many devices. This means that MiniDexed just has one knob that also acts as a clickable button, and does not need the many buttons found on the DX7 instrument. Hence, the descriptions regarding the buttons on the DX7 do not apply to MiniDexed, but all buttons have equivalents in the MiniDexed menu.

This is how you operate it:

• Rotate the knob to select items and to adjust parameters. Whenever you can rotate the knob to the right, you will see -> on the screen. Likewise, henever you can rotate the knob to the left, you will see <- on the screen
• Double-click to open a submenu
• Click once to leave a submenu

Once you have learned the basic menu navigation, we can use the following notation to describe how to nagigate anywhere in the menu structure:

MiniDexed -> TG1 -> Voice

This means that on the MiniDexed start screen (which you see when switching on MiniDexed), you select TG1 (which is selected by default), then double-click to open it, then select Voice (which is the default), then double-click to open it.

If you are asked to go to another menu item in the same submenu, e.g.,

MiniDexed -> TG1 -> Detune

then you click once to to go out of Voice where you were before, then rotate the knob to select Detune, then double-click to open it.

Note that double-clicking brings you, e.g, from

Open MiniDexed -> TG1 -> Voice

to

Open MiniDexed -> TG1

from where you can select Voice to go to

Open MiniDexed -> TG1 -> Voice

Exercise 1: Playing a voice

1. Open MiniDexed -> TG1 -> Voice (this is the parameter you are editing)
2. Rotate the knob to select one of the voices
3. Observe that the display shows the number and the name of the sound you have selected
4. Play notes on the keyboard. You hear the sound of the selected voice
5. Rotate the knob to select other voices

Exercise 2: Does not apply

Exercise 3: Editing a voice

1. Select any random voice like in Exercise 1
2. Play notes on the keyboard. You hear the sound of the selected voice
3. Now remove the SD card
4. Play notes again. The sound is still there even though you removed the SD card

Exercise 4: Adjustig the tuning

1. Select any random voice like in exercise 1
2. Open MiniDexed -> TG1 -> Detune (this is the parameter you are editing)
3. Turn the knob while you are playing a note on the keyboard and listen to the change in pitch. Then play a chord. Notice that the pitch of all notes changes the same amount
4. Select a different voice like in exercise 1. Play notes on the keyboard. The pitch is changed in the same way, because changing the Detune parameter is not voice-specific

Exercise 5: Key transposition

1. Select the E.PIANO 1 voice like in exercise 1
2. Play a scale on the keyboard to confirm you hear an electric piano sound
3. Open MiniDexed -> TG1 -> Edit Voice -> Transpose
4. Note that the bottom line says C3
5. Rotate the knob to the right to select D3
6. Play the same scale on the keyboard again and NOTE that the whole sound is now one note higher, as it has been transposed by one full note
7. Repeat: Rotate the knob to select another amount of transposition, then play the same scale on the keyboard again

Chapter 3: The Operator

(to be continued)