Nord Modular E Tribe-A Description
This Nord Modular and Nord Micromodular patch is a concise simulation of the bass synthesizer that is currently marketed by Korg known as the Electribe EA-1. This patch provides one-half of what Korg packages together in the product.
The E-Tribe A is a simple two oscillator synthesizer designed to produce a wide range of harmonically interesting lead and bass sounds. The basic patch is configured to be used monophonically. However, given its relatively low usage of DSP resources it can also be used effectively as a polyphonic instrument.
Feature-wise the synthesizer consists of two oscillators each with a variety of waveforms. These then drive a low pass filter with adjustable sharpness of 12, 18, or 24db. The signal path then feeds the standard envelope controlled amplifier. A final stage of effects processing provides adjustable distortion and two effect sends to drive an external delay and reverb unit as a way of example.
Portamento is provided and is triggered through legato play. Adjustments are available for determining the effect that velocity has on both amplitude and filter dynamics.
Two envelope generators are provided, which is more then the standard Korg unit. The first is a simple attack-decay/release (two time constants) which is used to drive the filter cutoff frequency as well as providing optional pulse width modulation of oscillator 1. A second is a full ADSR envelope for volume control but, aside from its release setting, is basically hidden unless the user decides to program sounds using the Nord Modular's edit features.
Various interactions between the two oscillators create rich harmonic starting material beyond the normal waveforms. Both oscillators offer switchable waveforms SAW, SINE, TRIANGLE, and PULSE. OSC2 PULSE is fixed at 50% duty cycle while OSC1 has an adjustment for pulse width as well as pulse width modulation. The output of each oscillator drives a balance control that lets the user selected the amount of each oscillator that feeds the filter.
The two oscillators are both driven by the same frequency control so they will track notes played. OSC2 features both an offset control and a fine control that lets the two oscillators be detuned. The offset control lets the oscillators be set to fixed intervals and also plays an important role when combined with the cross modulation capabilities.
Three cross modulations can be selected. The first is SYNC where OSC2 is hard sync'ed to OSC1. By altering the frequency interval between the two classic sync waveforms can be achieved.
The second is ring modulation. OSC1 modulates OSC2 amplitude and creates resulting AM spectrum. The modulation is not balanced by design so the center frequency component of OSC2 will be present. This can be adjusted if desired within the patch through the editor but has the side effect of making OSC2 inaudible when it is not in the AM mode.
The final is linear FM of OSC2 by OSC1. A modulation depth control allows setting of the modulation index.
The plus version adds MIDI remote control of patch parameters. Critical timbre
parameters have relative adjustments. This affords sound adjustments as changes to the current patch settings. So instead of setting say the filter cutoff directly you increase or decrease it from the setting when the patch was first recalled. These parameters have the convention that a value of 64 is neutral - no affect on the patch setting. Values below 64 progressively decrease the setting; values above 64 progressively increase the setting.
Parameters that offer relative adjustments are: Attack, Decay, Release (for the hidden AMP envelope); Decay for the Filter envelope; filter envelope amount; filter cutoff and resonance; and an overall "timbre variation" adjustment that is wired through a morph controller to allow you to set the degree and nature of varying the timbre.
These features consume a little bit of DSP and slightly increase module count. However the plus version still manages to come in under 50% DSP usage so one slot can hold two E-Tribe A patches.