USING A SOFTWARE SYNTH: THE KORG M1 (SOFTWARE) SYNTH INTRODUCTION In this lesson we are going to see the characteristics of the Korg M1 software synthetizer. As it is remarked in http://en.wikipedia.org/wiki/korg_m1, The Korg M1 is the world's first widely known music workstation. Its onboard MIDI sequencer and palette of sounds allowed musicians to produce complete professional arrangements. the M1 became the topselling digital synthesizer of its time The production of the M1 finished in 1994, but Korg delivers a software synthetizer that produces exactly the same sounds as the M1 by software means. This is the one that we are going to use for this lesson. We will see the differences of this synth w.r.t the synth used in the course, and how different parameters can be configured to alter some of the M1 synth sounds. The graphical user interface for this keyboard is shown in Figure 1
Figure 1 The M1 software synthetizer s graphical user interface
As can be seen in the figure, the synth is able to work in polyfonic mode (POLY). Also for both oscilators different waveforms can be selected. ADSR parameters can be used for both filtering and amplitude. We will see its characteristics in the following sections. SYNTH MAIN SELECTORS There are many features that we are not going to show in this lesson, in particular, there is a set of buttons in the upper part of the interface that allow us to edit other synthetizer parameters; these are: Figure 2 Main buttons for the software synth BROWSER Allows to select programs COMBI uses combination of sounds, that can be used in layers MULTI allows us to use several combinations of sounds in different MIDI tracks. GLOBAL Global settings for the synth. All these settings will not be explained in this lesson; in fact, they are not needed in order to show how the sound is produced. Instead we will concentrate on PROG (program)
which is the option selected in red, and allows us to edit the characteristics of a particular sound. In Figure 1 we can see that we are editing an M1 program whose sound corresponds to a piano 16. A program in the M1 terminology corresponds to a particular sound (note that this term is used in most synthethizers as well). By modifying the PROG settings we will see the differences in the sound produced by this keyboard.
PROGRAM (SOUND) PARAMETERS USED IN THE M1 Figure 3 shows the basic components used in the M1 synth for the sound generation: Figure 3 M1 Basic Sound Generation
Note the slightly different terminology used: The voltage controlled filter (VCF) is called the Voltage Digital Filter (VDF). As in the case of the Oscillator, there are two Voltage Digital Filter(s). The voltage controlled amplifier (VCA) is called the Voltage Digital Amplifier (VDA). Here we have also two of these, one for each oscillator. Sound can be produced in single (one oscillator) or double (two oscillators) mode. For the sake of simplicity, we will use only the single mode. There is also a set of buttons that allow us to select the parameters to edit for the VDF, VDA, OSC, these are the controls shown in figure 4: Figure 4 Sound generation parameter group s selection CONTROL and INSERT FX (effects) parameters are also out of the scope of this lesson. For the sake of simplicity, we will use the EASY option, that allows us to modify basic OSC, VDF and VDA parameters, without having to get into much detail. We will use the EASY mode editing to see how changing these parameters affects the sound.
EDITING THE VDF PARAMETERS In Figure 5 we can see : Figure 5 Easy editing of OSC, VDF and VDA parameters
Only OSC1 is used (OSC MODE=SINGLE) A Piano sound is used (MULTISOUND 1). Level indicates the level of the output of the OSC1. Separate envelopes (ADSR) can be used for the VDF and the VDA. We will demonstrate the envelope parameters for the VDA in the next section In VDF1 parameters, the cutoff frequency is set to 60%. We can also see that the resonance is set to OFF. This is sound of the piano, with the parameters shown: http://soundcloud.com/jioa/piano16 m1 cutoff 60 Now by lowering the cutoff filter to 22% (see picture) we get a much duller piano sound: http://soundcloud.com/jioa/piano 16 m1 cutoff 22
Figure 6 VDF parameters modified to get a duller sound Next, we increase the resonance, setting it very high, and some particular harmonics of the piano are now highlighted the sound of the piano is somewhat metallic: http://soundcloud.com/jioa/piano 16 m1 cutoff 70 Figure 7 Setting high resonance
EDITING THE VDA PARAMETERS Next, we will modify different VDA parameters, using a different sound, a guitar sound. Figure 8 Attack, decay, sustain, release applied to the VDA With these parameters, the sound is the following: http://soundcloud.com/jioa/guitar m1 a0 d77 s0 r05 That is, ADSR parameters are: Attack time 0, Decay 77, Sustain 0, Release 05.
Modifying the decay time, and raising a bit sustain level, now we have some resonance of the guitar at the end: Figure 9 Guitar with decay time and sustain level modified http://soundcloud.com/jioa/guitar m1 a0 d80 s02 r05 Finally, extending slightly the attack time, the sound changes radically, and it becomes much more similar to a violonchelo. Note that still there is a lack of resonance due to the decay, sustain level and the release time: http://soundcloud.com/jioa/guitar m1 a20 d48 s18 r78
Figure 10 Attack time increased, sustain level increased
CONCLUSIONS In this lesson: We have performed an introduction to the Basic architecture of the M1 synth and some differences w.r.t the synth used in the course We have seen the characteristics and appearance of its Graphical User Interface We have seen different examples on using VCF cutoff and resonance parameters We have seen different examples on using VCA ADSR parameters