090419
Meet Der "Klangumwandler" and Dr. Nicholas L. Heck.

Musical Timbre Mutation - Frequency Shifting

For several years I´ve been interrested in the era of electronic music, particulary before it was fully known to any human what it was all about. The age of the 1950´ies and 60´ies I belive is a time window when tremendously unique experiments where made. They where interresting then and are still today, mainly because we will never this kind of effort and such setup of studios for "elektronische musik" ever again.
The origin and the owner of this picture is taken from this website:
http://www.inventionen.de/Geschichte/chrono/chronoindex.html

The Studio
The time was an experimenters time, a time consuming time, and an age of research and profound curiousity. And nothing was in advance fully evaluated in terms of how electronic music "should" be produced. The era used laboratory equipment and relized its fundamental materials thru it´s "atoms of sound", the Sine waves or rich harmonic Square and Pulse waves, varoius other combinations involving e.g. the 1/3 octave filter made new patterns out of various noises and the whole palette of the acoustic recordings now availabe on juxtaposed tape splices. Constructing timbre was an essential part of the work, and since no true or regular elaborative way was known a freedom was there and did not in terms of the time aspect have to be different from the duration of the mixing, editing, or multitracking. It was all a fluid process, very "forgiving".

Frequency Shifting - listening to a single sideband
An apparatus that went into the electronic music studio of the time was the Frequency Shifter. It is still around, but for some reason it´s treated with kind of respect and belived to be a bit secretive when it comes to the skills of the art of Frequency Shifting... or at least it is not as common in the various electronic studios today, like many other effects like phaser, echo, chorus, reverb, filter, vocoding or so. This is a pity, since it´s a piece of electronic ingenuity giving us just that - A key to be the exeperimenter again, you the composer can listen and try ad hoc, what ever you may have in mind - the process will sound yet a bit different, sometimes breathtaking and always take you there; To a sound you didn´t belive you could elaborate.

A little about modulaion theorie
In certain wireless audio transmission two signals appear, beaming out mirrorlike from the carrier frequency - i.e. the one you are tuning into in the radio. If you tune in slightly off that stations frequency, beautiful sound mutations appear. One of the bands is the mirrored one and has it´s frequency content reversed... High frequencies are low and vice versa. Here the sound is mostly beyond any recognition.
You can easily get to hear these sounds by listening to a Ring Modulator [also known as The Four Quadrant Multiplier] a cousine to the Frequency Shifter. Here the two bands are summed and cause a disharmonic (metal like) content unless simple and even frequency relations are used. 1f 2f 4f 6f etc. But always having only access to the blended signal at it´s output gives us severe limitations. If we split them up into separate A & B matter, a vast collection of tricks can be performed.

The Klangumwandler does this, and is a piece of simple Electronic Radio electronic techniques combined. And when this is used the bands are apart at two outputs- You can listen to either one.. or perform seamless glide in and out between them easily. When you apply noise type sounds it transposes those over a wide range, all seems natural. But when you apply musical sounds it transpose them in a linear way, adding a frequency to the signal. This feature casues it to be so rich, so out of this world; For no sound behaves like this in nature. Each overtone gets the same knock up or down, as the fundamental when shifting occours. Any interval that goes higher in pitch in nature needs to be adjusted by a factor of the double for our first overtone and the quadruple for the second overtone.. and so forth.. it´s not the case when this type of "frequency adding" is done.

Freedom
A klangumwandler is Not constructed with a composer in mind, and therefore leaving you alone... letting you be tucked into it´s thick foggy sound, knowing the art of exploration. Letting the process of a sound design be; A modular, a harmonic one, a matter of balance, a strictly mathematic one, a disharmonic timbre welding, orded or totally oblique, or just for spatially minute refinement, infinate...it is yes... It´s a 100% analog process and therefore lacks any dealy, any latency. What ever on your mind, this radio technique of using single sidebands (SSB) has a lot to still to give to us composers if we dare trying it. It´s like a tasty treat.

Über precise
Now, we should be cautious in attitude and careful in beliveing that a computer nowdays can do this just as good. For it can´t. The computers way o doing this is ofcourse by sampling a signal and already there you havee a spliced up time factor - with grains of sound - not coherent. It has also to emulate the way the special All pass-filter [known as the Dome filter] behaves. That filter is needed to get a signal into two different outputs with a derivative function. 90 degrees apart at any given frequency thru a clever design that gives a comulative shift always with a 90 degree raltion. In the analog realm this in fact means a signal can leave the "Dome" output at 90 degrees before it arrives it´s input. Computers need to calculate this process and it is done by a Fourier transformation technique, A Linear Transform Approxiamtion wich is always a trade off between accuracy and computational power. No known computer today can emulate the allpass filters work in any equivalent way. The sound therefore from an analog apparatus doing this is far superior as it leaves out nothing, infinately small time fragments make it thru. It´s by definition incapable of missing any thing in the sound input.

The Frequency Shifter is very versatile, in fact it´s an understatement, and I know no other electronic sound treating device capable of such rich timbres and variations, and especially when you put it together in chain with any of the above mentioned effects.

Dr. Nicholas L. Heck
Now, who constructed this machine originally?
We are told by American composer Vladimir Ussachevsky in 1958 that it was invented by two engineers. Dr Nicholas L. Heck.and colleague Mr. F. Burek of the Southwest German Radio, in the 1930´ies. It was later refined into musically outstanding performance and versatility by Dr. Harald Bode in the 1960´ies. Here now, is a photo I found of one of the fouders Dr. Nicholas L. Heck. It was taken around 1940. I will try to find out what other machines he designed, working in the fields of Radio Acoustic ranging and beeing Head of division of Terrestial Magnetism and Seismology at NOAA corps corperation, then in the United States. I will also do my best to find a photo and a little more info on his colleague Mr. F. Burek.

Dr. Nicholas L. Heck, of NOAA, father of Frequency Shifting

Technically speaking
I intend to come back with a extensive post on the whole subject of Frequency Shifting and a description of linear transposing. To put some clarity and give you the simple answer to what it exactly does, and how it can be connected together with all our other known effects to give surprising sounds and results never preconsidered. It´s technical description - fundamentally would be; the differance and/or the sum of two signals AZ & BZ which are the products of two signals applied, who´s elongation has a derivative relation and are led into the X inputs of two four quadrant multipliers. Their Y input sources are the sine and the cosine [y =(sin x)] & [y =(cos x)] i.e. the exact same frequency, but with a (1/2) pi lag or lead with respect to each other.
The sum will produce the A + B and the difference the A - B frequency.

Heimcomputer
Connection to today and the Sound of Timbre Maestro Schneider: Much of the sounds Produced for KRAFTWERK´s rythmical structures, particulary heard on the track "Heimcomputer" from 1981 are created thru Florian Schneiders varoius elaborations and new cumulative soundeffects that an experimenter would typically "stumble up on" when exploring the fantastic realms of sounds the Klangumwandler beam us into.
// 090419 Fredrik N