Synth Interfaces

Contents

• Introduction
• Digital parameter access
• Making digital parameter access easier
• Paged interfaces
• Roland SH201
• Jomox Sunsyn
• The remaining problems

Introduction

Analogue synthesizers originally used controls that were part of the circuit. Altering the control actually altered the value of a circuit component. Consequently every parameter of the synth that could be altered was visible as a knob or a switch on the control panel. Later programmable synths replaced these direct controls with control voltages, but for a while the association between an editable parameter and a single knob remained. For many people, this remains the ideal, as it allows you to see clearly what options are available to the synthesist, and what the current values are.

Digital parameter access

When sound synthesis went digital, so did the method of editing, and digital parameter access was born. All the knob and buttons of previous synths were gone, replaced by an LCD screen and generic controls for altering values. The link between a particular knob and a particular parameter had been broken. This fitted well with the eighties fashion for cool minimalism, since it could be done with a handful of buttons and an LCD, but it didn't make anyone's life any easier.

However, digital parameter access allowed manufacturers to add many more parameters to their synths than had been practical before. This increased the range of sounds, although some might argue that the strict choice of parameters on old analogue synths helped to focus the minds of the designers.

The desire from musicians for the simpler interfaces of old analogue gear has lead to revival of the form. So how can synths cope with a large number of parameters, whilst keeping editing simple with a knob-per-parameter, or something close to it?

Making digital parameter access easier

At its worst, digital parameter access can be done with a numeric keypad and an enter button. You can type in the number of the parameter you want to edit (e.g. “Filter Cutoff” – Parameter 37) and then type in the new value, or perhaps alter a data slider. This makes for an extremely minimal and conceptually simple interface, but one which is very slow and tedious to use. Not all 1980's synths went this far. The Kawai SX240 is an interesting case. It uses a separate button to select each parameter for editing. The Roland Alpha Juno (1986) and Moog Source (1981) have similar interfaces. This at least means that you can see the parameters available to you, and are only a single button press away from editing any particular value.

Paged interfaces

Computer software initially, and websites subsequently, have used paged interfaces for a while. Examples are the tabbed palettes in Photoshop or similar programs. These are often represented visually like a series of old library file cards, with a tab on the top that shows the title. One card is regarded as being ‘in front’, whilst the others are ‘behind’. These interface elements became popular on software and websites because many options needed to be displayed at once, and screen area is limited. These are exactly the same limitations as on a synth front panel.

Consequently, paged interfaces have started to appear on synths to help reduce the number of knobs required whilst keeping things simple. One nice example is the recent Roland SH201.

Roland SH201

The SH201 analogue modelling synth has deliberately set out to mimic the look of its elderly relatives in the SH family.

This synth even uses a ‘tabbed’ metaphor to make it a little clearer what is going on. Both the Oscillator and the LFO section have this.

This allows the synth to ‘re-use’ the knobs for one oscillator for the other. It remains simple from the user's point of view since there is a dedicated button on the tab to switch back and forth between the two oscillators.

Jomox Sunsyn

Another synth which does something similar is the Jomox Sunsyn. The synth has four ‘routing elements’ which are sophisticated virtual patch leads. Each element can connect to two sources, be affected by a modifier, and sent to one destination. All four routing elements are displayed and editable in the section in the bottom right-hand corner. The LEDs display the sources, modifier and destination for the current routing element, whilst the buttons underneath allow edits. The central button switches between the four routing elements.

The remaining problems

The SH201 has one problem remaining, which it shares with all the programmable analogue synths. As soon as you use a sound from the memory, the knob positions stop having any relation to the sound you hear. Most programmable analogue synths have a ‘manual’ button which plays whatever sound is set up on the front panel controls for this reason. The Korg Polysix is one example - the manual button is the dark grey one in the middle.

The most effective solution to this problem is ‘virtual pots’. These consist of a rotary encoder surrounded by an array of LEDs to indicate the position. Clavia's instruments often feature virtual pots, with their Nord Lead 3 being one example.

One advantage of this technique is that software can be flexible about how it uses the LEDs. Using two colour LEDs is feasible with these displays, so the possibilities are quite large. You could use the LEDs as a bargraph meter on a ‘Audio Input’ control, for example.

Finally the knobs can show you exactly the sound you are hearing, even from memory. If you change to a different sound, the LEDs representing the positions simply change to show the new values.

The Sunsyn's routing elements also have this feature, since they are controlled entirely by buttons, and displayed entirely using LEDs.