PPG Wave 2.2, photo by John R. Southern, from Wikimedia Commons

The Wave was a digital wavetable synth made by PPG in the early-to-mid 1980s, which employed the wave scanning method of synthesis. Painted an inconic shade of blue, the Wave series were one of the first affordable and stage-usable digital synths, and were seen being used by many '80s-era synth players who were looking for new sounds.

The Wave synths were based on a model PPG released in 1978 called the Wavecomputer 360. This contained the basic wave scanning mechanism that would be employed by the later models, but it had few wave modifiers or modulation mechanisms. It also had some aliasing issues, owing to the limitations of the available CPUs at that time. Consequently, the sound was described as "buzzy" and static, and PPG sold fewer than 50 of them. However, Wolfgang Palm listened to the criticisms and set about producing an improved model, the original version of which became known as the Wave 2.

The Wave 2 used improved processors to do a better job of generating the output waveforms (which, however, were still stored at 8-bit resolution). And it added filtering in the form of analog voltage controlled filters, employing the Curtis 3320 4-pole lowpass VCF for the purpose. This considerably improved the timbral possibilities and helped performers take some of the "edge" off of the produced sounds. A low frequency oscillator and additional envelope generators were added. The Wave 2 was 8-voice polyphonic, with a single digital wave-scanning oscillator per voice.

The Wave 2's panel layout set the style for the subsequent models. A set of knobs to the left controlled mainly the analog functions. Digital functions, such as wavetable selection and interpolation points, were controlled using a numeric keypad, a second keypad for function selection, and a two-line LCD display. Many parameters were crammed into the LCD display by using a number of abbreviations, some of which were explained by graphics silkscreened on the panel around the display. The panel used white graphics on a deep blue background, the color of which would come to be associated with PPG products. The original Wave 2 was first produced in 1982 and remained in production through 1983.

The Wave 2's performance controls consisted of a keyboard with a 61-key span, and a single modulation wheel. There was no dedicated pitch wheel, although the mod wheel could be assigned to pitch. Patch memory held 200 patches. An accessory controller keyboard with the nomenclature "PRK" was offered. This had a 72-key span with keys that were almost but not quite piano weighted, and a set of function buttons that allowed some functions, such as patch selection, to be performed remotely. It interfaced to the synth via a proprietary interface. An interesting additional function of the PRK was that memory boards containing additional wavetables could be installed in it, and then when connected, these additional wavetables became available to the synth.

Only a year after the original model, PPG introduced an improved model referred to as the Wave 2.2 (there was no 2.1 model). The most immediate improvement was the addition of a second, independently tunable and scannable oscillator to each voice. The SSM 2044 VCF replaced the Curtis 3320, although the Curtis ICs used for the VCA functions were retained. Wavetable memory was expanded (still 8-bit resolution), and the keyboard gained a second mod wheel. However, the most interesting new feature was the ability to interface with a new device called the Waveterm, a rack-mounted device with two 8" floppy drives, a set of function keys, audio inputs, and a large green monochrome monitor. The Waveterm allowed the performer to build new wavetables, either by sampling and processing or by computing mathematical functions, convert them to the memory format required by the Wave 2.2, and download them into the synth. It also contained extensive capabilities for visualizing and performing Fourier analysis on waveforms. In addition to being used directly by performers, the Waveterm created the possibility of building and selling sound libraries, which were distributed on floppy disk and loaded into the Waveterm using the floppy drives. The Wave 2.2. remained in production through 1985.

The final model was the Wave 2.3, introduced in 1985. This model had a number of significant improvements: it increased the bit depth of the wavetables from 8 bits to 12, eliminating a lot of the "grittiness" associated with the earlier models. It included a built-in MIDI interface, for the first time. (This was also made available as a modification for the 2.2.) It was multitimbral, and the unit's eight voices could each be assigned to any desired MIDI channel. There was also a separate analog output for each voice.

Several new peripherals became available with the 2.3. An upgraded Waveterm called the Waveterm B (with the original becoming the Waveterm A retroactively) produced 12-bit wavetables for the 2.3, in addition to a compatibility 8-bit mode for the 2.2. (It also had the capability to produce wavetables at higher bit depths, up to 20 bits, in anticipation of future Wave models which never appeared.) The Waveterm B replaced the 8" floppy drives with by-then-standard 5-1/4" drives. This worked in concert with an upgraded mode of the PRK keyboard called the PRK FD, which also included a 5-1/4" floppy drive. Wavetable floppies produced by the Waveterm B could be loaded into a Wave 2.3 using the PRK FD's floppy drive, which meant that performers could load all of their user-produced wavetables onto floppies, use the PRK FD to load them during live performance, and leave the expensive and rather fragile Waveterm back in the studio. Also, a rackmount version of the 2.3, known as the EVU, was made available. This could be used as a synth by itself, or a slave unit providing an additional eight voices to a Wave 2.3.

The Wave 2.3 remained in production until PPG ceased operations in 1987. By this point, less expensive digital synths had occupied much of the Wave's territory, such as the Yamaha DX7 and the E-mu Emulator series, and Ensoniq was producing a line of "Transwave" synths that used the same wave scanning method of synthesis as the Wave synths, but cost considerably less (albeit with nothing akin to the Wave/Waveterm set of capabilities). However, PPG was also in distress because of a matter having nothing to do with the Wave synths, that being the R&D costs of the Realizer. Palm chose to shut down rather than see PPG slide into bankruptcy, and production of the Wave synths ended.

All together, PPG produced about 1200 units of the three Wave models combined. Waldorf (the successor company to PPG) later went on to make a synth which it also named the Wave, which duplicated much of the PPG Wave 2.3's capabilities. The Wave was a very expensive synth and sold only a few units, but it led to Waldorf's popular Microwave series. Today, Waldorf markets a soft synth called the 3.V, which emulates most of the Wave 2.3 functions.