AndreasKrebsBlog

This is one of Doepfer’s older filter designs, nonetheless it is quite an interesting one. It offers four filter modes: Notch - Highpass - Bandpass - Lowpass, each with a separate output (so you may use it together with a switch or a voltage controlled mixer). Soundwise, it is a bit rough and would be a good companion for e.g. an A-108 or an A-106-6. It can self-resonante in all four modes and its 1V/Oct-scaling is among the most exact ones I know (so this may be used as an oscillator as well). Unfortunately, the special circuit CEM3320 (Curtis) is no longer available, so this filter will run out of stock. Technical details can be found on Doepfer’s Homepage:

http://www.doepfer.de/a121.htm 

I have used three A-110 VCOs (sawtooh, one A-110 is 1 octave below), driven by an A-155 sequencer and put into the filter with high audio level. Filter out is then sent into an A-132-3 VCA (controlled by an A-140 ADSR).

We start with Notch mode (0:00-1:22), then Highpass mode (1:22-2:53), Bandpass mode (2:53-4:30) and Lowpass mode (4:30-6:17). Within each mode, I start with no resonance and filter frequency only being modulated by a very slow LFO. Then I slowly increase resonance up to maximum, add ADSR modulation of filter frequency, decrease resonance back to zero and finally fade out.

Here we go:

 http://www.andreaskrebs.de/assets/media/A-121.mp3

Have fun,

Andreas

First piece of music this year. This is a rather “old-fashioned” one, I hope you will enjoy it!

Instruments used: Doepfer A-100, GForce M-Tron.

I’m starting with a little sequence: three A-110 VCOs (two triangle waves and a sawtooth) through an A-108 Ladder Filter (24 dB lowpass mode), an A-188-1x BBD and then an A-132-3 VCA. Filter and VCA are controlled by an A-140 ADSR, VCO frequency is controlled by an A-155/154/156 Sequencer with Quantizer. (The A-154 is triggered by a master clock.) At around 3:02, the sequence sounds quite unharmonic. This is due to some “spicing up” via heavy BBD frequency modulation… (listen closely and you will recognize the slight delay)

Straight from the beginning, we hear a percussive voice: this is made with several kinds of noise (A-117 / A-118) sent through an A-182-1 (flanger/delay mode) or an A-188-2 Tapped BBD, respectivly and then switched rhythmically with a combination of an A-182-1 Switched Multiple (manual pre-selection) and an A-152 Addressed Switch (driven by a master clock). Then we go into an A-124 Wasp Filter and an A-132-3 VCA. Filter and VCA are controlled by an A-140 ADSR.

The M-Tron (starting ca. 0:30) is used for melody / chord stuff, I like those cheesy flutes (and others) quite a lot… Played directly via keyboard (LMK2+ in split mode).

The percussive voice is soon (ca. 1:57) accompanied by a bassdrum-alike sound: white noise (from an A-118) through an A-105 SSM VCF and an A-132-3 VCA. To create some atomatic bvariations on drum length / tone, the Filter and VCA are controlled by an A-142 VC Decay (with a random variation on decay length via A-149-1 Stored Random Voltages).

Starting at ca. 4:05, reappearing ca. 8:28, there’s a solo (doodle) voice: two A-111 VCOs, one being processed by an A-137-1, the other by an A-137-2 and then mixed with some sub-octaves from an A-115 and finally filtered with an A-106-6 XP VCF (24dB lowpass mode). VCA is another A-132-3, VCA and VCF controlled by an A-140 ADSR. After this, an A-127 Triple Resonance Filter is used in conjunction with an A-138m Matrix Mixer: the three individual outputs of the A-127 are spread in stereo via two output channels of the matrix mixer. This voice is played directly via keyboard (LMK2+ in split mode).

Finally - after ca. 5 minutes - you will hear a sequenced bass line: another three A-110 VCOs (pulse width modulated square waves) through an A-101-3 Phaser and then then an A-108 Ladder Filter (24 dB lowpass mode) and an A-132-3 VCA. VCF and VCA are controlled by an A-140 ADSR, VCO frequency is controlled by another A-155/154 Sequencer.

Both seqencers are transposed manually via keyboard (LMK2+ in split mode, connected through a Kenton Midi interface). Recorded and mixed with Ableton Live, Mastered with Steinberg Cubase 6.

Here we go:

http://www.andreaskrebs.de/asets/media/improvisation-20110131a.mp3

Track length: 12:03.

Have fun,

Andreas