AndreasKrebsBlog

Another new piece of weird music. Here we go:

http://www.andreaskrebs.de/assets/media/improvisation-20110529a.mp3

Track length is 14:18. Instruments used: Doepfer A-100, Arturia CS80V, GForce Minimonsta. No Overdubs.

I’m starting with two bass sequences (spread left/right in stereo) and a bassdrum. After ca. 48 seconds, the left bass seems to get out of rhythm, at 1:07 the right one as well. What happened? I’m reducing the length of both sequences while the bass drum keeps on doing its quarter rhythm. Each of the two bass lines is made of three A-110 VCOs (2 x sawtooth and a triangle wave 1 oct below), an A-138 Mixer, an A-108 Ladder Filter (24dB mode). Then we go into BBDs (left bass: A-188-1X, right bass: A-188-1A, both will be used later for some flanging), A-131 VCAs and into the two sections of an A-101-3 Vactrol Phaser. The bassdrum is some noise from an A-117 put into an A-101-2 Lowpass Gate (LP mode) and an A-188-1D BBD. Phaser and all BBDs are modulated by LFOs, and we have some A-140 ADSRs (used for both VCA and VCF).

At 1:25, a fast sequence (mainly repetitions of the same note starts). This is an A-111-5 Minisynth module, sent into an A-188-2 BBD. Later on (around 4:00), there will be some colored noise from an A-118 mixed into the audio input of the A-111-5.

Around 1:55, two high-pitched pad voices appear (panned slightly to left and right): An A-111-1 VCO (sawtooth) sent into an A-137-2 Wave Multiplier (modulated by an A-143-9 QLFO),  an A-102 Diode Filter and an A-132-3 VCA (left voice). An A-111-1 VCO (pulse) sent into an A-127 Triple Resonance Filter, an A-106-6 VCF (4Pole LP mode) and an A-132-3 VCA (right voice).

At 2:10, I start playing some cheesy strings on an Arturia CS80V. Keyboard ist split up, so I can transpose the analog synth sequences with my left hand.

At 2:40, a few notes on a GForce Minimonsta are added (more later), played on a second keyboard (I misused my MS20 Replica controller for this …)

Starting at 4:26, the two bass sequence’s BBDs are slowly driven into self resonance.

Around 5:05 a strange, quite distorted sound is faded in: this is done with four of the VCOs mentioned above (one from each of the left and right bass, left and right pad, only sine wave outs are used), sent into an A-172 Max/Min and both outputs (”max” and “min”) sent into two A-106-1 Xtreme filters (with some LFO modulation). Until 6:10, I’m having fun creating some heavy metal chaos. Then everything is reduced to bassdrum and the fast sequence (now only colored noise, the A-111-5 VCO is switched off), the bass lines slowly reappear.

At 6:50, the A-101-2 LPG modulation intensity is increased, resulting in a bass drum with more presence. The A-111-5 filter cutoff is modulated manually. Some Minimonsta doodeling around 7:20. At 8:55 the CS80V strings reappear.

Around 10:00, everything is reduced to basses and high-pitched sequence (and some filter fun). Bass sequences are in random mode now (i.e. notes were selected by chance, rhythm of the sequences thus is random as well). Sequences are created with two A-155/154/156/150 combinations, together with an A-113 (for master clock divisions), an A-162 Trigger Delay, an A-149-1/2 Random Generator (for the two pad voices) and an A-151 Sequential Switch.

Have fun,

Andreas

The Max / Min is a much underrated audio tool. Did you even know it? You possibly regarded it as some kind of freaky elektronic calculator (maybe useful for some kind of weird modulation stuff). In fact, it is a very interesting waveshaper. Much like a clipper, you can feed an audio source (e.g. a sawtooth from a VCO) and a constant voltage in two of its four inputs - and you will have clipping signals at both “max” and “min” outputs.

You may, however, use two or more audio sources as input signals - this little unit will create two different output signals with combined waveforms: one output will only use the higher, the other one only the lower parts of both waves. And these parts will change dynamically, if your audio sources are slightly detuned.

Technical details can be found on Doepfer’s homepage:

http://www.doepfer.de/A172.htm

For my little audio example, I’m using two A-110 VCOs: one with its sawtooth, the other with its pulse output, both VCOs are sent directly into the Max / Min. The two “Max” and “Min” outputs of the A-172 are spread left and right in stereo. No filters, no VCA. I’m starting with 100% pulse, and decrease pulsewidth slowly by hand. Then I start detuning the two VCOs a little. Here we go:

http://www.andreaskrebs.de/assets/media/A-172.mp3

Have fun,

Andreas

This is a piece of music with two sequencers being slightly out of sync (and with independent master clocks). As you can imagine, this was to some extent inspired by ideas Steve Reich already had in the sixties.

Instruments used: Doepfer A-100.

Right from the beginning, we hear two voices spread in stereo: both are controlled by two independent A-155/154/156/150 Sequencers (Sequencer, Controller, Quantizer and Switch for 16-Step mode). Clock frequencies have been manually adjusted and will drift during the piece. Both voices are quite similar, each one is based on three A-110 VCOs (all VCOs: individually modulated pulse waves, same ocatve), mixed (A-138b) and put into two different filters: An A-105 SSM Lowpass for the voice panned more left and an A-102 Diode Lowpass (with its beautiful “crystal” overtones) for the voice on the right side. Both go through A-131 VCAs, and finally into an A-138m Matrix Mixer. VCAs and filters are controlled by A-140 ADSRs, triggered by the (active) sequencer steps and by another A-140s, triggered when the sequencer switches from steps 9-16 back to steps 1-9 (using the resp. Sequencer Controller trigger and inverting it).

After a while, I’m adding some slight BBD delays to both voices - done with an A-188-1D and an A-108 for the left side and an A-188-2 and an A-108 for the right side (the A-108s are used to filter the BBD-internal clock noise which is quite audible with low clock frequencies as used here). Delays are mixed to the opposite pan position (left voce’s delay will appear on the right side) via A-138m.

If you already know some of my music, it will be no surprise that “music” will start after no less than two minutes: I’m adding additional sequencer steps. As soon as I do this, there’s some additional percussion: it is triggered only when the Quantizers (used for the sequencers) begin to detect different notes. I’m using both rising and falling edge of the A-156 Gate signal (via A-165 Trigger Modifier). Again, we have a percussion voice connected to the sequence panned left and one for the sequence panned right. Left: an A-117 Digital Noise put through an A-106-5 SEM Filter (LP mode), an A-188-1X (for some flanging) and an A-132-3 VCA. Filter and VCA are controlled by an A-140 ADSR. Right: an A-118 Noise (colored) put through an A-124 Wasp Filter (HP mode), an A-189-1 VC Bit Modifier and an A-132-2 VCA (also with A-140).

Finally, we hear some pad-alike sounds (again separate voices for left/right). Left: An A-111-1 VCO through an A-137-1 Wave Multiplier I (modulated by an A-143 Quadrature LFO), an A-101-3 Vactrol Phaser (12 Stages used with two different LFOs), an A-106-6 XP Filter (2 pole LP mode) and an A-132-3 VCA. Right: An A-111-1 VCO through an A-137-2 Wave Multiplier II (modulated by another A-143 Quadrature LFO), an A-127 Triple Resonance Filter, an A-121 Multimode Filter (LP mode) and an A-132-3 VCA. Here, I’m using two A-142 VC Decays put through an A-170 Slew Limiter (since I wanted to have long attack phases even with very short gate signals) as VCF and VCA envelopes. Triggers are created by some logic AND operations of left and right side sequencers (A-166 Logic, A-152 and A-160/161 Clock Sequencers as well as manual gate length adjustment via A-162 Trigger Delay are used for this). Pitch of the pad voices is created by two random generators in an A-149-1 RCV module sent through the two Quantizers mentioned above (internal jumpers are set for similar operation of both quantizer channels - thus I’m using “minor chords” quantisation for all four pitch control voltages).

The rest are variations on sequencer lines (with increasing complexity), expanding tonal ranges, some fooling around with BBD delay times, etc.

Here we go:

 http://www.andreaskrebs.de/assets/media/improvisation-20110418a.mp3

Track length: 16:21.

Have fun,

Andreas

The A-102 is a 24 dB lowpass which uses diodes (and not transistors), which leads to quite unusual resonance behaviour (resonance is dependant on filter frequency). The filter can easily be overdriven, which adds some interesting harmonics. In this sound example, I use three A-110 VCOs (sawtooth, one VCO tuned down 1 octave), mixed and put through the A-102 and then into an A-132-3 VCA. Both VCA and filter are controlled by an A-140 ADSR, the sequence is made with an A-155/A-154 Sequencer.

Technical details on the A-102 can be found on Doepfer’s Homepage:

http://www.doepfer.de/a102.htm

• We start with comparably low input level, no resonance and cutoff frequency at minimum. Then I manually increase cutoff frequecy up to maximum and back to zero.
• Starting around 0:35 same procedure, but with medium resonance (value ca. 3)
• From 1:10 on: full resonance.
• Then back to zero resonance, but from 1:50 on maximum input level.
• Starting at 2:25 we hear medium resonance again (full input level).
• Finally, around 3:05 we have max resonance and max input level.

Here we go:

http://www.andreaskrebs.de/assets/media/A-102.mp3

Have Fun, 

Andreas