Sequent is a modular multi-effects unit, the perfect tool for mangling audio on stage or in the studio. The effects - including a flexible beat looper and a pair of filters capable of self oscillation - can be connected in practically limitless combinations by simply dragging virtual cables between them.
Each effect parameter can be sequenced with a step sequencer (or which there are twenty-two), controlled live via a midi controller, or even left to chance by using the random mode. Sequences are combined into patterns which can be switched instantly between using either the on-screen interface or the notes on a midi keyboard.
Sequent will shortly be available to purchase at the Loomer website for £49 GBP, for Mac OS X (Audio Unit, VST, RTAS and Standalone), Windows (VST, RTAS, and Standalone), and Linux (VST and Standalone). An free evaluation version will be available for download at launch.
A sneak preview of some new oscillators. These have several advantages over the current Aspect oscillators:
Reduced CPU usage: They use, on average, about 30% less CPU resources. When taking the rest of Aspect's synthesis path into account, this translates into approximately a 10% reduction in CPU resources for a patch.
Reduced memory usage: Overall memory usage for oscillators is reduced by an impressive 80%, although this doesn't have much of an impact to the user.
Reduced aliasing and foldover noise: Aliasing and foldover noise at the ultra high end of the frequency range is reduced to practically negligible amounts. Here are two examples. Note that these are unfiltered raw oscillator sweeps, so ensure that your volume is at an acceptable level.
The first example is a sawtooth sweeping from the low to the high frequency range, and then back again:
The second example is a pulse wave with a duty cycle of 50% sweeping as in the previous example:
Removed DC Offset: There is no DC offset when sweeping the pulse-width of the Pulse waveform.
Reduced Sync Folderover Noise: Aliasing that could occur during an oscillator sync is significantly reduced.
Awesome sound: We can't quantify this one, so let your ears be the judge. Here are two raw sawtooth oscillator, with no filtering, tuned octaves apart. The pitch of one oscillator is slowly detuned relative to the other to introduce beating:
The Lag Generator Component The Lag Generator slews the input Modulation Source, reducing the speed of changes. Similar to how Glissando causes note pitches to slide into one another, the Lag Generator can be used to make any Modulation Source slide. As the Lag Parameter increases, more time is taken for the Modulation Source to slide between changes.
Slewed Filter Cutoff This example uses the Lag Generator to slew a Square waveform LFO which is modulating the Cutoff Frequency of a Lowpass Filter.
Set LFO1 to Square shape, and Sync it to a rate of 1/2.
Connect LFO1 to the Lag Generator.
Change Filter1's Cutoff to about 50% and Resonance to about 30%.
Connect the Lag Generator Modulation Source to the Cutoff Modulation, with a Depth of about 90%.
Hold down a note whilst slowly increasing the Lag Parameter. At low values of Lag, the Modulation Source still resembles a Square waveform. As Lag increases, the Square wave is softened and audible slides between the high and low values of the waveform can be heard. At higher values of Lag, the waveform starts to resemble a Sine, and eventually reaches a constant when the Lag is so much that any changes are too small to be heard.
Emulating a Magnetic Tape Player This example uses the Lag Generator to filter the White Noise Modulation Source. This creates a signal that slowly moves between random values (this type of movement is called Brownian Motion.) When used to modulate Pitch, this generates a meandering, detuned effect similar to the wow and flutter of an old tape recorder.
Connect the Noise Modulation Source to the Lag Generator.
Set the Lag to about 70%.
Oscillator1 should be a Sine shape, with a Pitch of 1 Octave up.
Connect the Lag Generator Modulation Source to Oscillator1's Second Pitch Modulation Source with a Depth of about 40 semitones.
The Adder Components The Adder components, Adder1 and Adder2, each take two Modulation Sources and produce a signal that is equal to the sum of the inputs. Because Parameters are already able to sum Modulation Sources (due to the fact that they all have three independent Modulation Slots), the Adder components may seem of little use. However, there are occasions when combining Modulation Sources outside of Parameter Modulation Slots is useful:
You may wish to connect several Modulation Sources to a component that only has one input connector (such as the Lag Generator, Sample & Hold, or Inverter components). Use an Adder to combine the Modulation Sources, and then connect this single Modulation Source to the chosen component.
If all of a Parameter's Modulation Slots have been assigned, and you need to add another Modulation Source, you can combine multiple Modulation Sources into a single one with an Adder. This single Modulation Source will allow two Modulation Sources to use up only one Modulation Slot in a Parameter.
The Adder can be used to combine signals to produce custom waveforms. This waveform can be fed directly into either Filter by choosing Adder1 or Adder2 from the Filter's input selector. The following example creates a waveform by subtracting one slightly detuned oscillator from the other:
Detune Oscillator2 by -1 cent.
Connect Oscillator2 to Inverter1.
Link Oscillator1 and Inverter1 into Adder1's inputs.
Choose Adder1 as the input to Filter1.
By summing an out-of-phase Sawtooth Oscillator with an inverted Sawtooth, we get a Pulse waveform. To add a bit of time-varying interest to the sound, an LFO will be used to add movement to one of the raw Oscillator sources:
Set LFO1 to Square, and Sync it to a rate of 1/4.
Link LFO1 to a one of Oscillator2's spare Pitch Modulation Slots, and give it a Modulation Depth of 12.00 semitones (remember: holding Shift will allow finely grained changes to be made to controls.)
The Sample and Hold Component The purpose of the Sample and Hold (S&H) component is to keep a Modulation Source's value steady for a short time. The component takes two inputs, a Source and Clock; whenever the S&H Clock input source changes from a negative to a positive value (known as a zero-crossing), the current value of the S&H Input source will be taken and held steady until the next zero-crossing.
Here a Noise source is periodically sampled by the Sample and Hold component, with the sampling period controlled by a Sawtooth LFO connected to the Clock input. This creates a Modulation Source that changes to a different random value at the same rate as the LFO. To configure this in Aspect:
Connect the Noise Modulation Source to S&H Input.
Connect LFO1 to S&H Clock.
Set LFO1 to a rate of about 7Hz.
Connect S&H to Filter1's first Modulation Slot with a Depth to 100%.
Set Filter1's Cutoff to about 30% and Resonance to 100%.
This S&H Noise to Filter creates a classic synth sound you've no doubt heard before:
Sample Rate Reduction with the Sample and Hold Component With Aspect, because there is no difference between Audio and Modulation signals the Sample and Hold component could also be used to sample an audio source at a specified clock rate. This distortion is known as Sample Rate Reduction, and produces a lo-fi, crunchy timbre.
Connect Oscillator1 to the S&H Input, and Oscillator2 to the S&H Clock.
Select S&H as the Input for Filter1.
Tune Oscillator2 up by 2 Octaves, and Tranpose is to 8.
Reduce the digital harshness slightly by setting Filter1 Cutoff to 50% and add a little bite by turning the Resonance to 50%.
The pitch of Oscillator2, which is used to clock the Sample and Hold component, sets the Sample Rate of Oscillator1. Changing the Pitch of Oscillator2 changes the Sample Rate. At 2 Octaves and 8 Semitones, the Sample Rate is just over two and a half times the pitch of Oscillator1. This produces a particularly aggressive lo-fi metallic-sounding digital synth texture, which sounds like:
What is Modulation? Aspect's flexible patching and modulation system can be a source of confusion to users more used to synthesizers with a fixed architecture. In synthesis, to modulate a parameter means to change the parameter's value whilst the sound is playing. This adds interest to what would otherwise be dull, static sounds. Most synth users are familiar with the basic modulation sources - envelopes and LFOs (low frequency oscillators). One common arrangement is the modulation of an oscillator's pitch by an LFO, producing vibrato. Another is the modulation of a filter's cutoff frequency by an envelope, resulting in a sound that has varying degrees of brightness as the higher frequencies are dynamically removed.
The Aspect Semi-Modular Synthesizer Aspect is a synthesizer in the tradition of semi-modular synthesizers like the Korg MS-10 and Korg MS-20. The appeal of these instruments is not only in their fantastic analogue sound, but in their versatility. Re-routing means that any nearly any component can be used as a modulation source. The Patch panel expands this concept by allowing modulation sources to be combined and transformed in various ways. Download Aspect for Windows, Mac OS X, and Linux, in Audio Unit, VST, and RTAS Plugin formats.
Modulating Parameters Rather than a confusing web of patch cables strung between modulation sources and parameters, Aspect uses a wireless modulation system. Modulation sources for a Parameter are clearly displayed with both their name and Modulation Depth (the amount that a Modulation Source alters a Parameter). The Depth for a particular parameter is listed in relevant units. For example, Modulation Depth for an Oscillator is specified in semitones. In the following screenshot, we can see that Oscillator1 is modulated 12 semitones by LFO2:
The basic steps for routing Modulation Sources in Aspect are as follows:
To assign a Modulation Source to a Parameter:
Left-click the Parameter's Modulation combo box.
Select the required Modulation Source from the drop-down list.
To remove a Modulation Source from a Parameter:
Left-click on the Parameter's Modulation combo box.
Select 'Off' from the drop-down list.
To change the the Modulation Depth for a Parameter:
Left-click and drag the Parameter's Modulation Depth rotary control upwards to increase the Modulation Depth, or downwards to decrease it. Holding Shift whilst dragging allows fine resolution changes to be made.
The Inverter Components Aspect has 2 Inverter components, Inverter1 and Inverter2, both of which perform the same function. They take a Modulation Source and output a signal that equal to the input source flipped upside down. The following diagram illustrates this concept:
One typical use of an inverted Envelope shape is in the creation of pad sounds. Here we have a pad sound through a Lowpass Filter, with the Filter'sCutoff modulated by an inverted Envelope shape. This creates a sound with an unconventional flourish at the end: where a pad normally grows duller during the Release stage as the Filter is closed, here it gets brighter during Release as the Filter opens.
Here is another example of an inverted Modulation Source. This tutorial on sequencing with a modular synthesizer uses an inverted SawtoothLFO routed to the Output Amplifier to produce a quick Attack and slow Decay repeating envelope shape.
Because all signals within Aspect can be used for Modulation purposes, even MIDI control data such as Note Pitch and Velocity can be inverted. The following Program illustrates this:
Start with an empty Program by clicking File / New Program.
Assign Note Pitch to Inverter1.
Replace Oscillator1's Note Pitch Modulation Source with Inverter1.
The Oscillator is now controlled by the inverted Note Pitch. As you move up the keyboard, the pitch of the oscillator decreases!
The Multiplier Components Aspect has 2 individual Multipliers units, Multiplier1 and Multiplier2. Both of these take two Modulation Sources and produce an output that is equal to the product (multiplication) of the inputs. This is particularly useful for producing scaled Modulation Sources. For example, assigning both LFO1 and the Mod Wheel Modulation Source to a Multiplier produces an LFO output with a Depth can be controlled with the Mod Wheel:
Set LFO1 to a rate of 5Hz.
Set the first input of Multiplier1 to LFO1, and set the second to Mod Wheel.
Set Oscillator1's second Pitch Modulation Slot to Multiplier1, with a Depth of 2 semitones (Modulation Slot 1 is left assigned to Note Pitch so that the Oscillator will still track the keyboard.)
LFOs that gradually fade up to their maximum Depth is another often used synthesis technique. Multiplying an LFO by an Envelope will accomplish this. In this case, the Envelope shape should have maximum Sustain. The Envelope's Attack parameter will govern how long it takes to fade in:
Part 2 of this tutorial will cover the remaining Patch Components, which are the Lag Generator, the Sample & Hold unit, and the Adders.
Start with a blank program configuration by clicking File / New Program.
A sequencer connected to a synth will trigger a succession of notes, where the volume contour of each note is controlled by the synth's amplifier envelope. This triggered envelope can be emulated by instead using a repeating modulation source to shape the note volume. We'll use a percussive volume contour: a quick attack, and slow decay. A Sawtooth LFO (Low Frequency Oscillator, in this case LFO1) will provide the shape we need, but from the following display we can see a problem: Aspect's Sawtooth LFOs ramp upwards, which is equivalent to a slow attack, and instant decay.
This is easily corrected by linking the LFO's output into an Inverter component (we'll use Inverter1 in this example). As you'd expected, this generates the shape we need (see diagram below.)
Which, when connected to the Output Amp Modulation and Synced to a rate of 1/16, produces the following 16th note pattern:
The remaining 2 LFO components will be used to make the notes within our sequence play at different pitches. Both LFO2 and LFO3 are set to Synced Square waves. LFO2 is set to a rate of 1/8, and LFO3 to a rate of 1/4. when we align all three LFO signals we can clearly see a short sequence that repeats every four 16th notes:
The LFOs now need to be connected up as modulation sources to their required destinations. LFO2 should go to Oscillator1's second Pitch Modulation slot, with a depth of 2.00 semitones. (Remember that holding down the Shift key whilst dragging a rotary control will allow for more precise changes. This is useful when exact modulation depths are required.) LFO3 should be connected to Oscillator1's third Pitch Modulation slot, this time with a depth of 7.00 semitones.
With LFO2's Square modulation output causing Oscillator1's Pitch to move between 2 semitones up and 2 semitones down every 16th note, and LFO3 causing a modulation of 7 semitones, up and down, each 8th note, we get the following jaunty pattern repeated every four 16th notes:
Due to Aspect's flexible semi-modular architecture, even without a dedicated sequencer interesting melodic patterns can be created. We've explored the simplest example - using LFOs to control a note's pitch - but for the more dedicated sound designer, Aspect's audio rate modulation sources and Patch section components provide the building blocks for a wealth of complex sequencer-style patterns.
