'This touch thing'

Wolfgang Palm, a Hamburg-based musician and inventor, has had a hand in many of the technological developments in music since the 1970s. As a keyboard player, Palm started off making analog synthesizers. But he soon found himself moving into digital synthesis for a very practical reason: It was a lot of work keeping the old analog synths in tune. These days, DJs and electronic music producers say that's one of analog technology's many charms - the fact that the sounds it produces are unpredictable. But for Palm, it was the reason he invented wavetable synthesis. Wavetable synthesis is a digital technology. It's a more reliable method of changing audio waveforms to modulate the sounds they create. Artists like Depeche Mode, David Bowie, Propaganda, Jean Michel Jarre, Gary Numan and Tears for Fears (among many others) all fell in love with the technology. Their music shaped popular sound for a generation and continues to influence electronic music today.

A lot has happened in the three decades since. But most recently, Palm has produced some highly-acclaimed iPad apps that in part recreate the old magic of wavetable synthesis, while also taking advantage of the new possibilities offered by mobile touch screen technology.

In this interview, Wolfgang Palm explains some of the basics of analog and digital audio synthesis. For help with some of the synthesizer terminology, check out vintagesynth.com's great glossary, or soundofmusic.se's Analog Synth School (links below).

DW: What made your early synthesizers - your early digital synthesizers - different from the old analog ones, like the Minimoog or those by Electronic Music Studios (EMS), ARP Instruments or Buchla?

Wolfgang Palm: Well, I started making analog synthesizers in the mid-1970s, and everything worked using low pass filters… and that typical stuff. [Low pass filters reduce the amplitude of signals above a certain frequency, set by a "cut off." They produce lower, bass sounds.]

But then there was always a problem with pitch instability. If the temperature in the room rose, the octaves and the scales went out of tune. That was always a problem! And it brought me to the idea of developing digital oscillators. [In music, oscillators generate a basic, periodic signal, or sound, which is then modulated with filters, amplifiers and envelopes to give the sound character or harmonics.]

My first digital synthesizer still had an analog filter and an analog VCA [voltage controlled amplifier], but only digital oscillators, which I called digital controlled oscillators, or DCOs.

I then discovered that if you have a digital oscillator, it's not a big step to change the waveform. You didn't have just a sawtooth or a pulse wave [standard waveforms in analog synthesis which determine how a sound is changed]. But you could make many, unique waveforms. Say for example a cycle of a waveform has 128 steps. If you change these steps, you get different waveforms and different sounds. And so slowly the idea evolved to have this wavetable principle, which I was the first to use.

So, tell us about the wavetable principle, because this is something that - probably without knowing it - a lot of people have heard on countless records, whether it's Depeche Mode or Stevie Wonder. What is really happening there? It's how you create the sounds, isn't it?

Yes, how the machine creates the sound. As I said, a cycle has different steps. You can compare it with a movie: You have these frames, let's say, 24 frames per second, which means you have 24 pictures which run through in one second. And in the wavetables it's the same principle. You have, let's say, 100 different waveforms, and if you change the waveform from one to another in one second, and you play these 100 waveforms, then you have what we call a wave sweep, which you can again compare with the movie. If you run all the pictures very fast, you don't see the pictures anymore, you just get the evolving image. In sound it's the same, you get [the evolving sound], a sound sweep.

And so, moving forward… a couple of decades, you're now producing iPad apps. Is that a natural progression for you from the original synths that you made?

What can I say? I did a lot of research and development in the three decades since the 70s… and I did a lot of work with speech analysis, and speech synthesis, and all kinds of models which you use for synthesizers. I can't say it was a natural progression… But the WaveGenerator app, that is a kind of reproduction of the old work from the 70s.

So, if today's tablet technology and touch screen technology had been available back in the 70s or the 80s, would these have been the synths that you would have made back then?

Yes. I mean, the touch thing is just a nice way to control the parameters. But you can also control the parameters with a computer mouse or with a knob. But, yes, the iPad has very nice features because, for instance, with three fingers you can control X-Y parameters [in three ways]. It's like having three mice, so that's a great thing!

You can also take photos through the app and use the images for the basis of your waveforms - so that's totally unique. Have the developments in software and design changed the way you want to make music or create sound? Also, these apps are tiny, just about 30MB, compared to what used to be a massive piece of physical hardware. So has that changed the way you want to make music and create sound?

That's hard to say. Today, you can produce a sound which has 200 sine waves, and each sine wave would have an individual envelope. But nobody can control that. I mean, would you want to control 200 envelopes just to produce one sound?! The old subtractive synthesis is one easy way to create sound, just with a low pass filter and with a sawtooth wave, or something. But that's only one way.

[Subtractive synthesis is the type generally used in analog synthesizers.]

But there are so many synthesis models, like physical modeling… So, this wouldn't depend on the iPad, or on the hardware. But about the size of my apps: They are so small because I don't use samples, like most others, and by using wavetables, you get a reduction of about 10:1.

You've mentioned the iPad, but there are many different platforms. And more and more producers and DJs are using mobile platforms in the production of music. Are we getting to the point where mobile devices and apps are more than just toys - a point where we can talk about their being real instruments themselves?

Yes, I think so. Of course, there will always be the classical hardware, like a flute or a trumpet, and there will always be keyboards with a standard piano keyboard. But I think the iPad - with these touch features - gives you quite new possibilities which you don't have on a keyboard. That's very interesting. I don't think people will play all their music on the iPad, but some solos or things which you can't play on a keyboard, things which are very nice on a touch screen. So, I don't think it will replace the hardware keyboard, but it's a nice addition for musicians.

Wolfgang Palm invented Wavetable Synthesis in the 1970s and 80s under the name Palm Products GmbH (PPG). One of his most successful synthesizers was the PPG Wave 2.3 (pictured above). He later worked with another German synthesizer company called Waldorf Music (formerly Waldorf Electronics GmbH), and through German software developer Steinberg GmbH released the "softsynth" PLEX. He now produces iPad apps, including WaveGenerator and WaveMapper under the name PPG.