An exceptional banjo sound, a single oscillator and monophonic layout might not look very tempting to today's keyboard players. The lack of knobs and sliders would probably upset synth enthusiasts like you, searching for endless sonic possibilities. The ARP Prosoloist is something of an exceptional character.
It is a classic from the 70ies, just like the Minimoog and Odyssey, it was used by famous bands like Genesis, the Chick Corea Electric band and Steely Dan. However, even these people did not really seem to appreciate the ARP.
Tony Banks complained about the flimsy keyboard construction and according to their website, Donald Fagen threw a Prosoloist from the stairs, repeatedly jumped on it and set the keyboard on fire after a frustrating recording session.
Presets for performers
However, the Prosoloist had a particular advantage. It allows you to do a thing we consider almost boring today: quickly change between preset sounds. The Minimoog was already a step ahead in user friendliness, you didn't need to change patch cables between the synths modules anymore, as on modular synths, and could dial in a sound by turning knobs.
Still, it took a considerable amount of time to switch from a bass sound to a flute leadsound or a pad sound, and the resulting patch would sound slightly different each time. The Prosoloist has 30 sounds that could be changed simply by flipping a switch.
| MP3 - Mix File |
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Flicking Switches |
Several ARP soli with drums & Fender Rhodes
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Roald Lingbeek
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The initial design for the synthesizer was simply called Soloist and relied on fully analogue circuits to control the single oscillator, and the filter and VCA envelopes. This turned out to be highly unreliable so the improved model, the Pro Soloist, had primitive digital control circuits to combine different analog filter modules in different ways to create a specific preset sound. The main filter is the wonderful 'stolen' moog ladder filter, however it is the combination of additional filter modules (as far as I know all-pass filters with a fixed resonance frequency) that make the Prosoloist sound so characteristic. The Prosoloist was eventually replaced by the Pro/DGX, which was advertised as a digital synthesizer as the preset selection switches were replaced by 'digital' buttons. All other circuits are identical except the filter, that was replaced by an ARP design.
With these resonator filters 6 groups of presets were created, reeds, woodwinds, brass, strings, percussion and a final preset switch for 'fuzz guitar'. If this sounds very organ-like to you, you're right, the Prosoloist was also specifically intended for home-use, on top of an organ. There exists an ARP Demo record where we hear the Prosoloist in action over a very bad organ and rhythm box, playing horrible trumpet melodies. ARP synthesizers are well known for their brass and woodwind sounds and the Prosoloist's best presets are also in these groups. Some sound remarkably realistic, some have a more synthetic character, you could even simply call the clarinet a 'square lead'.
| MP3s - ARP Pro Solist presets |
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Trumpet |
ARP Pro Soloist preset, with reverb
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Roald Lingbeek
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Clarinet |
ARP Pro Soloist preset, with reverb
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Flute |
ARP Pro Soloist preset, with reverb
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Trombone |
ARP Pro Soloist preset, with "growl" and reverb
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Because there is only one oscillator, the sounds are very clear and sit in the mix very well. It is hard to say whether the ARP sounds 'warm' or not as this depends on the preset but you won't mistake it for anything else. Most brass sounds have a rather slow envelope, delivering wonderfully smooth and melancholic sound. You can achieve many things with the right effects, but if you're looking for fast and aggressive sounds you're at the wrong place. By setting the octave button in 'down' position you can change some sounds into usable bass sounds, but again, you won't achieve very snappy sounds with this ARP.
| MP3s - ARP Pro Solist presets |
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Cello |
ARP Pro Soloist preset, with chorus and filtersweep
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Roald Lingbeek
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Tuba |
ARP Pro Soloist preset, with "wow" and reverb
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Steeldrum |
ARP Pro Soloist preset, with reverb and filtersweep
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| MP3 - Mix File |
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Either Way |
This Fender Rhodes sounds so wonderful
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Roald Lingbeek
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Expression is the key
The filter cutoff is controlled with the 'brilliance' slider, you should be aware that the filter reacts differently on each preset due to the resonator circuits. It can also be controlled by aftertouch, another feature that was unique to the Prosoloist in the early 70s and that is still tremendous fun today. Besides the filter cut-off, aftertouch can control vibrato, volume, growl, wow and (upwards) pitch bend.
When an aftertouch effect is active it is cleverly disengaged from the preset sound: without aftertouch the flute sound will slowly develop vibrato, but sound straight when vibrato is controlled by aftertouch. The side effect of this is that when you flip switches like 'wow', which is a combined filter cut-off and resonance effect, the basic sound already sounds quite different. All 'touch sensor effects' can be freely combined, and depending on the preset, some pretty extravagant sounds can be created. Aftertouch sensitivity is controlled with a slider (a feature that each synth should have, just like the portamento time slider!) and feels very natural, not the 'on-off' feel that my other keyboards have.
Conclusion
If you switch on the synthesizer and try out a sound you get the feeling the synth says 'Play, play!' to you, it is very inspirational. However, you have to live with some of ARP's specific quirks. The build quality is not great, the housing consists of floppy steel and hardboard, the keys stick out at the front and the switches and sliders do not exactly feel reassuring. There are no CV input jacks, so sadly you cannot add another oscillator in the shape of a 'little brother', or secretly fake your favourite Tony Banks solo via a CV-midi interface. The strangest design quirk is that you always have to flip two switches to change a preset, the original one 'off' and the new one 'on', which takes some practising! However, if you flick the 'french horn' you'll forget all about that and find out that the limitations are actually cause of the fun. The Prosoloist makes you think in a different way, building the song around the sounds that you have, instantly trying out different sounds and the focusing on expression.
| MP3 - Mix File |
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ARP-World |
Pro Soloist with percussion & Yamaha CP70B piano, hmmmmm. "The world according to ARP" ...
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Roald Lingbeek
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Review, sounds, pictures: Roald Lingbeek
Mixing: Stefan Hoffmann
Layout: Theo Bloderer