Using the A-100 for Sound Processing

A-119 External Input /
Envelope Follower

The A-119 External Input / Envelope Follower module allows you to integrate any audio signal (electric guitar, microphone, midi sound module, computer sound card, CD player, tape-recorder ...) into your A-100 system.

Audio inputs of audio-processing A-100 modules (e.g. filter, VCA, phaser, flanger, waveform processor, distortion, wave multiplier, ring modulator, frequency shifter, spring reverb, panning ...) all require line level signals of around 1Vss. , and if the signal source does not have the required level an external pre-amplifier like the A-119 is recommended. 

This module consists of a (pre-)amplifier, an envelope follower and a comparator.

The pre-amp has 2 inputs, one unbalanced (Asymmetric) for line level signals, and a balanced (6.3mm jack /Symmetric) input for inserting low level signals, like microphones or electric guitars.
The module provides two simultaneous audio outputs of the amplified signal.

The envelope follower 'reads' an incoming audio-signal and sends out a proportional voltage as an envelope to its own output.
The brightness of the LED indicates the envelope output level, which is very useful...

The voltage at the output signal can be used to control the filter frequency, loudness or any other voltage controlled parameters such as filter resonance, LFO speed, clipping level, wave multiples, frequency shift, phase shift, delay time and more...

The comparator generates Gate signals out of the incoming signal.

Whenever the audio input exceeds a certain (adjustable) level, a Gate-signal is produced.

This signal can again be used to trigger various other external modules like envelope generators or even voltage controlled switching.

Again, this is a very useful module that i cannot do without anymore because i often use external audio inputs. Most of the times i have a microphone plugged in for vocoder use or for filtering pleasures, but i have used it with my guitar and other audio too.
I do find it a bit strange that it is not included in one of Doepfer's pre-configured basic systems, for me it was a must-have.

One Year www.PatchPierre.net

Wow... time flies.

Today exactly one year ago I started to write this blog, mainly because i could not find a lot of Doepfer user-info on the web. I was looking for a way to share my adventures in analog sound with others, and i looks like i found the right spot.
Sadly i don't have any budget for a give-away (like the wonderful Din Sync blog did) to thank you for visiting/ commenting/ interacting but i do appreciate all your input in this first (and certainly not last) year.

A few statistics:

- A total number of 1000 unique visitors have visited this site so far
- Those visitors came from 77 different countries

- Coincidentally today the site passed the 6000 pageviews too.
- Last months the site has an average of 1000 pageviews per month (but that includes my own too)
- About 30% of the unique viewers are from the USA, The Brits and the Dutch share a second place with around 10% of the total unique viewers each.

Very different are the numbers of my PatchPierre Mobile Nokia application users. Sadly this app doesn't generate an extreme lot of traffic to the actual site, but it did generate around 5% extra visits.

4592 people have downloaded and installed the application so far.

Most of the downloads happened in the counties where Nokia Symbian is a big platform, so most of them happened in India (1067 downloads - 23%), Saudi-Arabia (274 downloads - 6%),Turkey (5.3%),Brazil (4.7%) and Italy (4.3%).

Interesting to see that counties like the USA, Great-Britain and the Netherlands even had less installs than countries like Egypt, Thailand, Indonesia, Russian Federation, Libya, Vietnam and Mexico, to name a few 'odd' ones.*

A lot of them probably used it only once to try it out, but there is a steady group that keeps using the app., around 75 people each month.

So, if you read this blog on your Nokia app, feel free to click through to the real site if you don't want to miss any of the links.
Let me know if you would like to have a Nokia app for your own Blogspot blog... I have two apps in the OVI appstore already, and it is definitely worth it.

There will be a couple of changes to the blog in the next few months. Due to my work i will have less time for the blog again this spring/ summer. I will not post every three days, like i did last 4 months, but i will try to post more than weekly. There are still plenty of modules to write about, and i believe i can't really write about the ones i haven't tried out by myself, but there's still enough stuff to come.
Let me know if you have special requests of topics that you would like to see discussed on the blog. Your input is always welcome, and i hope you will enjoy reading the blog in the next (few) year(s).

My Wordle of one year in Tweets, via http://tweetstats.com

* PatchPierre Mobile stats provided by @wonderhelm

Quotes VII : Herbie Hancock

" Creativity shouldn't be following ratio, it should be the other way around. "

Herbie Hancock - musician, composer, bandleader

Controlling the A-100 via MIDI

In the beginning it was not difficult to pick a Doepfer MIDI-CV interface for your A-100 system.
The A-190 MIDI-CV/SYNC Interface was the only one available and there were not many other options.  (the A-191 MIDI-to-CV Interface / Shepard Generator was way more complex, i will discuss it in a future blogpost).
The A-190 is a powerful module that not only provides a few CV and Gate outputs, but also Portamento, Scale-settings, Pitch-bend, Glide, Clock and Reset signals, has a built-in (software) LFO and very flexible programmability.
Without a proper display it is quite awkward to program, but you'll quickly learn how to read the combinations of burning and flashing LEDs.
I do miss some further (software) development for this module. The arpeggio function, mentioned on the front-plate isn't even implemented (!)

A cheaper option that you can buy nowadays is the  A-190-2 Midi CV/Gate interface, which is based on the Doepfer MCV4. Only some minor changes were made for a better adaption to the A-100 system, e.g. five 3.5 mm sockets and zero-symmetrical CV for pitch bend, to be able to adjust the pitch bend range e.g. in combination with the precision CV adder A-185-2 and the glide function.
The module has no MIDI Thru and MIDI clock and reset functions though.

The new A-190-3 USB/MIDI-to-CV/Gate Interface that is in production stage has almost the same possibilities, but will be a modular version of Doepfer's upcoming Dark Link Module. This one will support USB and the release date for it is set for early 2011.
Another advantage of these two cheaper modules is that they don't need the additional +5V adapter. 

If you are looking for a polyphonic MIDI-CV contoller you will probably have to wait a while. Doepfer is busy working on the A-190-5, but it will be completely redesigned this year. A final version will  probably contain an LC display (similar to the A-187-1), some control buttons, a USB interface and higher resolution DACs with higher voltage range (probably 12 bit and 0...+10V). It will be a four voice polyphonic Midi to CV/Gate interface with 12 CV and 4 Gate outputs and different modes (e.g. unisono, four-fold monophonic, different four voice polyphonic modes.)

Tip: The monophonic MIDI-CV converters can write and read to the A-100 Busboard, more info on this HERE

Booktip VII - Keyfax Omnibus Edition by Julian Colbeck

The Keyfax Omnibus Edition, written in 1996 by Julian Colbeck, is a pretty interesting 192-page book about synths and synthesizer history. It is the sixth volume of a series by the author, his first one appeared in 1985 although he already writes about synthesizers since 1976.

The book is divided into 2 main parts, The Hot 100 and the Product Directory.
The first and largest part of the book delves into the 100 most important synthesizers in history, alphabetically ordered by manufacturers name. Together with the company profiles this book gives a nice overview on the global history of synthesizers. I like the style that it is written in, very informative...

The second part, The Product Directory exists out of an extensive list of almost every synthesizer on the planet. The directory also provides production data like production year, release-prices, the instrument's value in 1996, and often a short extra description. Very useful if you are looking into buying a second-hand ( pre-1996 ) synthesizer.

The book reads like a synthesizer history book. It is a nice resource for anyone interested in older synths and synth history. PatchPierre rates it at 8 out of 10 stars

More PatchPierre Booktips

Published by Mixbooks,
later editions published by Hal Leonard Corporation
ISBN: 0-1918371-08-2

Filters II : A-121 VCF2 Multimode Filter

The first Doepfer filter that i ever bought was the A-121 Multimode Filter. It is a 12 dB/Octave filter, and has multiple simultaneous outputs available; a Low-Pass, Band-Pass, High-Pass and Notch (or Band Reject).
It also has 4 CV inputs, 2 for adjusting the cutoff frequency and 2 for resonance.

This is still one of my favorite filter modules, the multiple outputs are very useful, and i  like all the CV inputs. It just gives you so much more control over the filter, and that's what i like most in a module; maximum control.

Although it is 'only' a 12 dB filter it sounds very nice, from very smooth and warm up to quite rough, especially with the resonance turned up ( ...up to self-oscillation ).
Most of the times i patch an A-174-2 Wheels CV into FCV1, and a simple envelope CV to the (adjustable) FCV2. Works fine in most situations.
With some analog or digital noise added to QCV2 to give it a touch of unpredictable resonance you will quickly get a convincing fat bassline.

Together with an A-138 B (exp) Mixer you can easily make some pretty impressive stacked bass-sounds, all with just a single filter-module.

Find A-121 sound examples at Andreas Krebs Blog : HERE

As the special circuit CEM3320 used in this module is no longer available the module is discontinued. I believe there are still a few available, but they don't make new ones anymore. Doepfer advices modules like the A-106-6 ( with eight simultaneous outputs! ) or A-107 Multi-Type Morphing Filter as a replacement.

SiteTip IV : MIT OpenCourseware Music and Technology: Contemporary History and Aesthetics

A great resource for beginners and all other synthesizer-enthusiasts is the OpenCourseWare site from the Massachusetts Institute of Technology (MIT)

This course, as given by professor Christopher Ariza in the fall of 1997 is highly informative and perhaps a must-read to all of you new to analog sound or music in general.

'This course is an investigation into the history and aesthetics of music and technology as deployed in experimental and popular musics from the 19th century to the present. Through original research, creative hands-on projects, readings, and lectures, the following topics will be explored. The history of radio, audio recording, and the recording studio, as well as the development of musique concrète and early electronic instruments. The creation and extension of musical interfaces by composers such as Harry Partch, John Cage, Conlon Nancarrow, and others. The exploration of electromagnetic technologies in pickups, and the development of dub, hip-hop, and turntablism. The history and application of the analog synthesizer, from the Moog modular to the Roland TR-808. The history of computer music, including music synthesis and representation languages. Contemporary practices in circuit bending, live electronics, and electro-acoustic music, as well as issues in copyright and intellectual property, will also be examined'

Surfing through these pages you will find a lot of interesting information on (analog) sound, music history and much more, accompanied by many links to other interesting reads and audio-examples.

Video: Lecture 13 | MIT 21M.380 Music and Technology (Contemporary History and Aesthetics)


Preview Lecture 13 / Modular synthesizers
See the complete course HERE

Check the massive PDF (37 Mb / right-click and save as) for the complete set of notes and all other information on this course and enjoy!

Licence info:
Ariza, Christopher. 21M.380 Music and Technology (Contemporary History and Aesthetics), Fall 2009. (Massachusetts Institute of Technology: MIT OpenCourseWare), http://ocw.mit.edu (Accessed 16 Oct, 2011). License: Creative Commons BY-NC-SA