Interview with a Professional : Wolfram Franke



This interview appeared first on in German. I (Hans Heerooms) translated it in a rather free way... It tells the story behind the Waldorf/Steinberg Wave 2.x VST Plugin. Notice : This translation is not autorised by Amazona or Wolfram Franke !


Amazona :

How did the idea arise to make the PPG Plugin ?


WF :


In September 1999 I moved from TSI to Waldorf : I was a productspecialist at TSI and became a software developer for Waldorf. I managed to make this move because I already made the Waldorf D-Pole in 1997 : so Waldorf had a clear idea of my “credentials”. Just befor my move Steinberg had published the specifications of  VST 2.0 : And for us at Waldorf it was clear we should do something with it. We had a meeting with Mert Ergün from Steinberg to discuss what a Waldorf VST synth should be like. Mert came with the idea for a PPG synth . At first we didn’t like the idea : making a PPG instead of a real Waldorf synth. But still  Mert was that fascinated by the idea for a PPG that he ‘infected’ also Frank Simmerlein : one of Steinbergs’ graphic designers. Frank jumped behind his workstation and made a 3D PPG rendering. When we received this picture by E mail it hit us like a bomb : any doubt was gone and we were going for the PPG !


Amazona :

How hard is such a programming job ? Did it took long ?



In December the 3D rendering arrived, and in hours after the official “OK” from the boss I started. I fetched our “museum PPG” and placed it right aside my desk : so there was always a way to compare near !

I started with building the rough structure of the PPG architecture  to check if we were going in the right direction. Afterwards I made the Wavetable oscillators,filters, amplifier,LFO and envelopes, modulationmatrix and the user interface. Lucky there is quite an knowledge in these areas at Waldorf : so when I got stuck there was always someone to help me out. At Waldorf we have an extended Toolkit with programmodules and algorithms from which I used a couple. The clearest example : our filteralgorithm. This is used in the D-Pole but also in the DSP Waldorf synths. This algorithm was the basis for the PPG filter. Of course does a PPG filter sound different than a Waldorf one, but the algorithm is that flexibel that there was no problem to adapt it. In these early versions we used the same wavetables as in the Microwave II : these wavetable are identic in both PPG and Microwave, except for two waves and the Saxophone and Piano sample.


At the NAMM in the USA we had a first version which was for 75% a PPG... If you played the instrument you already got ”that is a  PPG” feeling. But still : I was not fully satisfied with the LFO and the envelope, and the scaling for times and rates of the parameters was not correct.


So between NAMM and the Frankfurter Messe was the time for fixes and additional features like the multimode and the arpeggiator.


At the beginning of March Beta testing and the port from Mac to PC started. We also extracted the wavetables from the original PPG Eproms and put them in the plugin. We also added the Saxophone and Piano sample, and when these sounded right Stephan Stenzel and I optimized the code to raise the possible number of voices.


At the time of the Messe the product was in fact ready. Unfortunately in the release version was a bug we never encountered in early versions. This bug slipped in by adding ‘workarounds’ for making the plugin work also with other host applications than Cubase.


“Naja”, It is ready now !!




During the programming : were you all the time listening to the real PPG to get an exact emulation, or were there other methods you used ?




That is possible and in fact the way I did it. The PPG stood all the time on top of my masterkeyboard and all the time I was comparing : pressing a key on the lower and then on the  upper manual.


To show you how some things were done :  All the attackrate values (PPG has 64 of them) were recorded on a hard disc recording system and afterwards  analysed in a sample editor. Also the shapes and times of the various parts of the envelope are so visible and were registrated. This whole game I repeated for all 70 parameters of the PPG, you can imagine how many hours I sat in front of this thing : both sampling and analysing. Also an oscilloscope was at hand so that always a doublecheck possible was.


It is very difficult to use hard disc recording for in dept analysis of the filtercharactistics. There are mathematical methods, but the human ear is much better and faster at this.


To give an example of this : If you program a filtersweep with high resonance on the PPG, then the PPG (at least the one I used !!) has two very short distortions in the resonancesignal in the last quarter of the sweep: these distortions are driven by the harmonics of the choosen waveform. I tuned the filtermodel that also these distortions appear at the right time and with the right amount.


Another check was that I asked a Beta-tester who owns 2 PPG’s to program the original factorysounds on the plugin. I asked him not to optimize and correct the sound by using the parameters , but  just to send me the differences, so that I could optimize the plug-in. He didn’t send me any E-mail...




There is already a Microwave software version for MAC/PC . Is the PPG plugin not just a re-released Microwave ?




Huh ? Did I miss something ? There is NO “native” Microwave. There is the Microwave PC, which is in fact a Microwave II without a frontpanel, but it has the same DSP as the real thing. Also there is the Waldorf Wavetable oscillator for Creamware’s Pulsar : still a DSP thing. If there is a software Microwave around it is not from Waldorf.




Let’s put it the other way round : what is soundwise the difference between the PPG plugin and the DSP Microwave, which was already a software model for the Microwave I, which was a ‘copy’ from the PPG-wave.... conclusion : they should sound all the “same” ???




First : the PPG has another basic character than the Microwave I, the II and the Wave. This is caused by the SSM filter and the used VCA’s. The PPG always had that “woody” sound, and is somehow rough and rude. For that reason it was in every 80’s production drowned in choruses , echo’s and reverb, often nearly beyond recognition. A Microwave or a Wave , or to be honest the latest generation of wavetable synths can be used also ‘dry’ in a production : the sounds are that good that an effect will spoil often the sound.


Second : the user interface: the way you have to operate a PPG dictates the way it sounds, for that reason the sounds you make are quite different from a Waldorf Wavetable synth. For that reason also the user interface of the plugin oughted to be comparable with the real one. I believe I managed well with the display pages. But some features we didn’t copy : they would lynch us. For example there is the second oscillator on the real PPG which is switched on if you turn the “SW” parameter to a value between 0 and 2, and 3 equals “off”. Got it ? NOT ! So we took the liberty to show the meaning of the values : Parameter “SUB WAVES” , values “Off”, “On” , “Direct” and “Env 3”. Still cryptic enough (big grin ).


Third : the limitation. It wouldn’t make sense when a range of the plug in was bigger than the original. So you get exactly the same LFO speeds , envelope times, filterfrequencies etc. For example : the LFO is always glued to the modulationwheel: the wheel controls the amount of LFO modulation. Lucky for us : In the real PPG wheel position is stored as part of the patch, and that is how it is done in the plug-in also.


Despite this we have put a bit more in the plug-in . Those “more’s” can be switched on and off with the 3 LED’s on the analog frontpanel. LFO can be synced to the MIDI clock, which results in a slightly larger range for LFO speed and so it is possible to make very slow LFO sweeps.


Further on we have put an extra stereo output, which makes mixing a easier : you don’t have to launch another PPG.


And most important : the “TRUE PPG” mode. The envelopes and LFO’s are calculated in ‘Original Quality’ if this is active, resulting in extremely strong quantisationartifacts. The LFO really eats itself. You also get aliasation and a bit off tuned filter, exactly like the real PPG.



Last question : Are there already new projects around ?



Yes, of course . But ... I can’t say anything about it. Just this : there will be an update soon for the D-Pole. This will have a new copy protectionmethod : so that also Mac users without a floppydrive can use it. And as icing on the cake the new D-Pole will be able to receive controllers and there is automatic tempo synchronisation with the sequencer.


Thank you very much for this in depth interview