miniSynth is a programmable analog-modeling keyboard synthesizer for the iPhone. Through combinations of its provided settings, it allows creating and sculpting various sounds. This is a brief introduction to the functionality provided with the miniSynth, and is by no means an exhaustive enumeration of its features or settings.

Controls

miniSynth has two control surfaces accessible during performance. These control surfaces contain the buttons and sliders that allow users to experiment with miniSynth’s sound.

Control Surface 1:

1) Oscillator 1 adjustment bank
2) Oscillator 2 adjustment bank
3) Keyboard octave/key controls
4) Current key/keyboard octave indicators
5) Control surface chooser buttons
6) Glide control bank

Control Surface 2:

7) VFC (variable capacitance filter) adjustment bank
8 ) Reverb unit console
9) Attack/Decay Filter adjustment bank
10) Master Volume
11) Presets Bank

Basic Mode of Operation: Oscillators

miniSynth offers two variable-frequency oscillators for its basic sound generation. The timber, loudness and frequency range (pitch) for these oscillators are controlled individually by settings in (1) and (2). After assigning waveforms, it is possible to obtain an optimal mix by adjusting the volume sliders for each oscillator. OSC 2 is provided with an on/off switch for one touch muting, whereas either oscillator can be effectively turned off by reducing its mix to 0 via the volume slider.

The row of buttons “Lo” - “32′” determine the interval of operation for each oscillator, with an effective range of approximately 5-7000 Hz. Increasing values correspond to higher pitches, with for example 8′ generating tones exactly one octave higher than 4′, and 16′ two octaves above 4′. The “Lo” button can transform either oscillator to an LFO mode of operation, where sub-sonic frequencies are emitted for certain types of percussive effect. It is possible to obtain octave coupling by setting the oscillators to different ranges, thus evoking a “fatter” sound.

Note that, as per miniSynth’s vintage design parameter, some frequency bleeding at certain range couplings is expected, a la classic transistor synthesizers.

Keyboard Navigation

For easier access on limited screen space, miniSynth is designed to display keys covering a one-octave range. It is possible to conveniently navigate miniSynth’s full 48-note keyboard during performance by using the buttons (3). While “< note” and “note >” buttons will shift the keyboard down or up, respectively by one white key, “-12″ and “+12″ buttons shift the keyboard by one whole octave relative to the current start note. The start note and current octave are displayed in (4).

Buttons in (5) are used to select between the control surfaces.

Glide

miniSynth includes a programmable glide unit, which the user can activate via its dedicated button in (6). The “glide amount” slider is used to set the amount of time miniSynth takes to glissando from the start note to the target note. The provided glide range goes up to 2 seconds for added effect.

VCF

At the heart of miniSynth’s sound is its vintage-modeling filter stage. By using the resonance and cutoff sliders provided in (7), the user can sculpt the basic waveforms generated by the oscillators, either statically (set-and-play), or dynamically during performance, effectively making the VCF a controllable instrument in itself.

Although there are no set rules at all about adjusting the VCF, a generally observed approach is to reduce cutoff (i.e. reduce threshold frequency) and keep resonance in the mid-range for bassy, non-obstrusive sounds, and to increase both cutoff and resonance for brighter, more cutting timbres.

Reverb

The reverb unit provided with miniSynth can be turned on or off via its dedicated button. The decay slider controls the volume factor of each successive repeat, while the time slider adjusts the length of delay. At slow-decay settings, it is possible to emulate a tape machine and layer sounds on a repeating backdrop.

Attack/Decay Filter

For additional sound adjustment, miniSynth provides the user with programmable attack and decay length. As a rule of thumb, use a longer attack/decay to emulate sounds of bowed/string instruments, or a low or zero-length attack for the sounds of plucked or percussive instruments.

Furthermore, the decay adjustment slider functions as a “Keyboard On” switch, when the decay is set to 0. In this setting, miniSynth will continue to generate sound even after you lift your finger off the keyboard.

Presets Banks and Master Volume

miniSynth provides ten factory sound presets (11) that the user can choose from, including six basic leads, two basic basses, and two ambient voices.

The Master Volume (10) is used to adjust miniSynth’s overall amplitude.