Arturia V- Collection - ARP 2600V (the theory)

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Arturia V- Collection - ARP 2600 V (the theory)

The ARP 2600V is the second “giant monster” made by Arturia, which recreates the feeling of the glorious ARP 2600 “semi modular” synthesizer.

 


INTRODUCTION

A brief history of the original instrument: the ARP 2600 was released on the market in 1972 by the “ARP instruments” company, founded by Alan R. Pearlman, David Friend and Lewis G. Pollock. In ten years, three versions of the ARP 2600 were commercialized: The first version was called “Blue meanie” because of its steely blue finish. The “blue meanie” was quickly replaced by a second version, with a grey background finish and white silk screening (1972). This was to be more popular. In 1978 ARP decided to change the graphic chart for all of its machines: a black background color with orange silk screening was introduced.

The synthesizer was used by Stevie Wonder, Joe Zawinul (Weather Report), Tony Banks (Genesis), Jean Michel Jarre, Herbie Hancock and during seventies the ARP company was the Bob Moog’s greatest rival on the market. There has been several episodes of this competition but probably the most famous one was related to the 24 db/oct filter module adopted for the 2600 that was considered a replica of the Moog’s one: due to this fact Moog’s company threatened ARP company with legal action and so the filter module was at last changed.

The emulation made by Arturia recreates the feeling of the original synthesizer, emulating also the original step sequencer module 1601 and the original keyboard module, which was also revisited during years by the company. 



 

For those who never knew the ARP 2600 synthesizer I suggest to take a look at its history visiting this (http://www.vintagesynth.com/arp/arp.php) page.

Let’s dive inside the software version made by Arturia, to learn in depth its features. First of all, this software version offers the emulation of:

1. The main synthesizer
2. The keyboard
3. The step sequencer

It also adds the capability of managing the presets, saving and recalling them and organizing them in categories, as in the Moog Modular V. The management of the presets is possible through the main toolbar on the topmost part of the interface of the synthesizer.

 

THE SYNTHESIZER

The ARP2600 (and its virtual version made by Arturia) can be considered a semi modular synthesizer: it can produce sounds also without connecting any patch cord and acting only on the sliders and the knobs on the main interface. This is because, unlike the Moog Modular and any other full modular synthesizer, inside it has “default” connections between its main modules (oscillators, mixer, filter, envelopes and so on) that the programmer/musician can decide to use “as is” or to alter using patch cords.



 

Looking at the main interface, the signal path starts from the left side and ends to the right side.



The sound programming section contains:

• 3 oscillators, which can also be used as modulation sources (VCO)
• 1 multimode filter (VCF)
• 1 amplifier (VCA)
• 2 envelopes dedicated to modulation
• 1 noise generator
• 1 ring modulator
• 1 envelope follower
• 1 sample and hold
• 2 mixers (on the filter and the VCA)
• 1 electronic switch
• A tracking generator module
• 5 mixer / lag module
• 2 effects (chorus / delay)

Let’s take a look at each section in depth.

OSCILLATORS




 

The ARP2600V offers, as the original machine, three oscillators. The main tune of them spans between 4 octaves and the musician can also set for each one of them the LOW FREQUENCY mode, in order to use it as a modulation source. Furthermore each oscillator can be adjusted in tuning using a “coarse” mode and a “fine” mode. The first mode lets the user alter the tuning of each oscillator of 2 octaves up or down. The second mode lets the user adjust the tuning altering it by cents of a semitone up or down.

The first oscillator outputs the saw and the square waveforms, the other two output all the waveforms available (sine, pulse, saw, triangle). Each oscillator can be pitch-modulated by several modulation sources: 4 for the first oscillator, 5 for the other two ones. For this purpose, 4 inputs for the first oscillator and 5 inputs for the other oscillators are available. Last but not least, only for oscillators two and three the pulse width can be modulated. 

If no “virtual cables” are connected using the mouse to these inputs, the default modulation sources are specified in the little boxes below the inputs. This approach is valid for all the inputs and the outputs of the synthesizer and that’s why we call the ARP 2600 V a semi modular synthesizer.

FILTER

 

Despite of the original machine that offered only a low pass resonant filter at 24 db/oct, the ARP2600V offers a multi mode resonant filter (LP, HP, BP, NOTCH). The low pass mode offers the same behavior of the original filter.

The frequency of the filter can be set to a value between 10Hz and 10 KHz.

The input of the filter is the sum of five the signals taken by the inputs on the bottom most part. If no cables are connected, default input sources are used, as shown in the box near each input. The level of each signal entering into the filter can be adjusted by using its own slider.

The cutoff frequency can be modulated by three modulation sources, using the same mechanism of the default inputs and adjusting the modulation amount using three sliders.

 

ENVELOPES




Two envelopes are offered, an ADSR and an AR. For both envelopes, the musician can:

1. Set the input trigger. If no input is used, the keyboard gate is the default signal used
2. Fetch gate and trigger signals and route them to other destinations
3. Choose to activate the envelopes cyclically using the S/H clock

 

VOLTAGE CONTROLLED AMPLIFIER



 

The VCA is the last step in the synthesis path. It amplifies the volume of the signal in input and sends the amplified signal out of the synthesizer.

The VCA of the ARP 2600 V receives in input the mix of two signals. The default ones, if no cables are connected, are the output signals from the VCF and from the ring modulation components respectively.

The volume of the output signal can be modulated by two modulation sources and, again, the default ones are the AR and ADSR envelopes. A general gain slider is also offered to the musician to let the synthesizer produce drones.

 

NOISE GENERATOR

 



 

The synthesizer offers also a noise generator that is able to produce white or colored (pink, brown etc.) noise. The output of the module can be routed almost anywhere (for example to the sample and hold module).

 

VOLTAGE PROCESSOR



 

 

 

One of the most interesting components offered by the ARP 2600 V is the voltage processor. It acts as a sort of mixer: it receives 8 sources in input (audio or modulation signals), mixes them and outputs them, giving the musician the possibility to invert each output signal or to smooth it (for example, a square wave became a triangle one).

 

In details, for each of the four rows:

1. There are two input that can be mixed together
2. There is a modulation input source to modulate the mix of the two input signals
3. There is a “link” switch that merges the output signal with the one produced by the row above. The merged signal is output from the row above
4. There is an “invert” symbol that, if clicked, inverts the output signal (a bit hard to discover that the symbol is clickable)
5. There is a smooth knob, to smooth the waveform produced as explained above

 

SAMPLE AND HOLD



 

Another powerful module is the sample and hold, which is typically used to produce cyclic modulations starting from an input signal. The module accepts signal to sample using the top left corner input, samples it using a clock (internal or external) and outputs the sampled values from the “S/H out” output.

 

If no cables are connected:

1. The default signal sampled is the output of the noise generator module
2. The default clock is the internal one

In the ARP 2600V it’s possible to sync the clock to one supplied by the external sequencer in which the synth is loaded.

Using the “electro switch” part of this component, the musician can make the sample and hold module sample two signals, connected to A and B inputs alternating the sampling process between them.

 

ENVELOPE FOLLOWER AND RING MODULATION



 

Using the envelope follower, the musician can generate an envelopeto use as a modulation source, starting from ad audio signal connected to the “PREAMP” input. Using the slider near the out jack, the musician can modify the way the envelope is generated: the lower it is, the more closely the variations of the input signal will be followed.

The ring modulation allows the musician to multiply two signals in order to generate non-harmonic frequency components. It is useful for creating metallic sounds. If no signals are connected, the output of the module is the result of the multiplication of the saw wave with the square wave.

TRACKING GENERATOR



 

This very original module was not present on the original machine. It has been added to the ARP 2600 V, in order to let the musician modify the course of a modulation thanks to four curves which can be edited in real-time by the user. It can also be used as source of modulation to create envelope forms or complex LFO waves.

MIXER AND EFFECTS



 

 

The mixer module fully reproduces that the original machines offered to the musician. There are two audio inputs that are by default connected to the VCA and VCF and mixed together. These signals can be taken in output before the spring reverb module. The main mix with the reverb is available on two stereo outputs, which can also be “panned”.

In addition to the reverb, the ARP 2600 V offers a delay and a chorus.

 

 

LOW FREQUENCY OSCILLATOR



 

 

The ARP 2600 V offers also a low frequency oscillator to be used as a cyclic modulation source. The LFO offers 4 waveforms: triangle, saw, square and sine. It can be also synced to the external midi clock and the rate can be modulated using an external modulation source using the “MOD IN” input.

 

STEP SEQUENCER

Before closing this tutorial let’s speak briefly about the step sequencer of the ARP 2600.



 

This module has been programmed as a copy of the original ARP sequencer model 1601 (18). It was one of the most widely used sequencers in the 70’s and early 80’s.                                                                   

With this module, the musician can create melodic sequences or step by step variations applied to synthesizer parameters (a sequence line applied to the opening of the frequency of a filter can be very effective, for example).

It can be divided in three sections, as shown in the picture above. The first lets the musician program the 16 steps that constitute the automatic sequence started by the module. The second, named “sequencer oscillator” lets the musician control the internal LFO of the module that makes the step sequencer proceed (start, stop, repeat, clock frequency and so on). The third section, the quantizer, lets the musician control the quantization of the steps using two signals in input.

Have you had enough? As you can see, the ARP 2600 V is a very complex synthesizer that lets a sound designer a lot of room for experimentations. But it requires a bit of practice to fully master it.

In the next appointment we’ll make some practice in programming it, as we did with the Moog Modular V.

Stay tuned!!
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