AndreasKrebsBlog

This is a very relaxed piece. Or not, depends on how you view it. The idea here is to have some kind of (nearly) “irregular”, “organic” processes controlling timbre, rhythm and - partly - pitch and some transitions between pitch, timbre and rhythm (which are basically the same thing - changes in time).

Here we go:

http://www.andreaskrebs.de/assets/media/improvisation-20100926a.mp3

Technical information, for those who are interested:

A first voice (panned somewhat on the left side) is built from two A-111 VCOs (pulse wave out used, 2 octaves apart), mixed and sent into an A-101-1 Vactrol VCF (only lowpass input used here). Then I go into an A-188-1X BBD, coupled with an A-108 VCF (48 dB to filter out the BBDs internal clock noise). VCA is an A-131, since it adds some nice distortion (together with the A-108). VCO pulse widths are modulated by two independent LFOs (tri and saw waves from an A-143-3 Quad LFO). The Vactrol VCF is modulated by another LFO (tri) from said A-143-3 and by an A-147 Voltage Controlled LFO (saw out). The BBD is modulated by the same VC LFO (sine out), and of course manually (this is a serious instrument by itself). The VCA is only modulated by the sine wave out of the A-111 tuned 2 octaves down.

The second voice (panned more on the right side) is based on three A-110 VCOs: 1 VCO with sawtooth wave put into an A-137-2 Wave Multiplier II (modulated by all four sine/cosine outputs of an A-143-9 Quadrature LFO), the other two VCOs 2 octaves down (somewhat similar to the first voice) with sine waves out. The mix is put into an A-124 Wasp VCF with level craked up to get some (different kind of) distortion here, too. LP/HP out of the filter is sent into another A-131 VCA. The VCA is not modulated.

Some noise - to blur things, to make structures a little bit more opaque. Colored noise from an A-118 is sent into an A-127 Triple Resonance Filter and then into an A-134-1 VC Panner, modulated by an A-146 Variable Waveform LFO (triangle out, more like a rising sawtooth).

A “percussive” voice: The digital noise output of an A-117 Digital Noise Generator is sent into an A-188-2 Tapped BBD and then into another A-108 (coupled with the BBD frequency) 24 dB lowpass filter to get rid of the BBD’s clock noise. After this, we go into an A-106-6 Xpander Filter, the 3H/1L output is sent into an A-132-3 VCA. The noise generator is clocked by the A-147 VC LFO (square wave output, sent through an A-160 Clock Divider, “/8″-division used here). A triangle LFO (A-143-3), sent through an attenuator (A-183-2) is used to modulate the A-147 VC LFO, the A-188-2 and the A-106-6. The digital noise pulses also triggers an A-140 ADSR, which modulates the VCA of this voice. This A-140 is also retriggered by an A-155/A-154 Sequencer (16 step mode via A-150 VC Switch), which is triggered  by said A-147 VC LFO (square out).

Finally, there’s a sequence line: another three A-110 VCOs (two pulse waves and one sine - 1 octave down) are sent into two A-106-1 Xtreme filters (first one configured as highpass, second one as lowpass). Then we go into an A-132-3 VCA. VCOs are controlled by said A-155/A-154 Sequencer, which can also control the first and second voice mentioned above (manually switched via A-185-2 modules). Both VCFs and VCA are modulated by an A-142 Voltage Controlled Decay - triggered by the sequencer and decay modulated by the A-143-3 triangle LFO (mentioned above, the one being sent through an attenuator, inverted here by an A-175 Voltage Inverter). The two VCOs producing pulse waves are PW modulated by an A-143-9 Quadrature LFO (sine and cosine).

Have fun,

Andreas

The A-117 is a versatile digital niose generator. It has two parts: an “808 Sound Source” which has a 6-oscillator output (cymbals) and a 2-oscillator output (cowbell) for percussive sounds known from an 808-style rhythm machine. The sound example here starts with the 6 oscillators output (through an A-132-3 VCA, controlled by a sequencer-triggered A-140 ADSR) and blends over to the 2 oscillators output (same patch). Quite a nice thing, if you like that kind of machines.

Then, we crossfade to the digital noise, which is  a kind of “Geiger-Counter”, here tempo-synced to the sequencer (i.e. the random clicks stay within the rhythm - just randomly switched on or off, which makes it quite usable in a musical context). Tempo / tuning of the digital noise can either be controlled manually or with an external clock source (sequencer, square LFO/VCO waveform). Later, the tempo is increased, until we have something that reminds of “normal” white noise:

http://www.andreaskrebs.de/assets/media/A-117.mp3

Detailed information can be found on Doepfer’s Homepage:

http://www.doepfer.de/a117.htm

Andreas

The A-188-2 is a Bucket Brigade Device with several taps and extremly versatile sound possibilities. It can be used not only for flanging and delay effects, but also for Karplus Strong synthesis as an oscillator. Here’s a short sound demo:

http://www.andreaskrebs.de/assets/media/A-188-2.mp3

Patch used: An A-155 Sequencer triggers an A-142 VC Decay envelope which controls an A-132-3 VCA (short decay time). VCA input is some noise from an A-117. VCA out goes into an A-188-2 BBD. The BBD frequency is controlled by the A-155 and an A-185-2 (to switch octaves - something like octaves: 1 oct down every 30 seconds).
In the feedback loop (the 396 stages tap is used here), an A-108 is inserted with bandpass out, no emphasis and manually changed filter frequency. BBD output is sent into another A-108 (filter frequency is controlled by BBD frequency VC out), the 48dB out is then sent into DAW.

Technical details on this module can be found on Doepfer’s homepage:
http://www.doepfer.de/A1882.htm

Andreas

The A-188-1 is a Bucket Brigade Device that can be used not only for flanging and short delay effects, but also for Karplus Strong synthesis as an oscillator. Here’s a short sound demo:

http://www.andreaskrebs.de/assets/media/A-188-1X.mp3

Patch used: An A-155 Sequencer triggers an A-142 VC Decay envelope which controls an A-132-3 VCA (short decay time). VCA input is some noise from an A-117. VCA out goes into an A-188-1X BBD. The BBD frequency is controlled by the A-155 and an A-185-2 (to switch octaves - something like octaves: 1 oct down every 30 seconds).
In the feedback loop, an A-108 is inserted with bandpass out, no emphasis and manually changed filter frequency. BBD output is sent into another A-108 (filter frequency is controlled by BBD frequency VC out), the 48dB out is then sent into DAW.

Technical details on this module can be found on Doepfer’s homepage:

http://www.doepfer.de/A1881.htm

Andreas