Thom and Jonny messing with Nigel’s vintage Sequential Circuits Prophet 5 REV3 during the recording of A Moon Shaped Pool.
As we say in our (slightly out of date) article A Synthesizer To Play Radiohead: “the most significant factor in a subtractive synthesizer’s tone is the tone of its filter: regardless of how many oscillators, waveforms, envelopes, and extra features a synth offers, it will always sound like its filter.” That’s one reason that many modern synths have added multiple filter circuits to choose from (for example the Sequential Pro-3, Moog One, and Novation Bass Station II).
And it’s doubly true if one synth has a 2-pole filter (like the OB6) and the other has a 4-pole filter (like the Prophet-6). If you’re a guitarist, you could think of 2-pole as brighter single coils and 4-pole as warmer humbuckers. You can make them sound similar by turning down the filter cutoff on a 2-pole, but the 2-pole will still have a gentler and more “natural” sound.
If you really love Radiohead’s polyphonic synth sounds, then you should get a Prophet of some kind (or at least a Prophet emulator like the u-he REPRO-5). The Sequential OB6 is a really great sounding instrument, but with its 2-pole filter it really sounds like an Oberheim, which was the goal of course. The OB6 may share some architecture with the Prophet-6, but the filter really sets them apart.
The Prophet-6 sounds very similar to the Prophet-5 REV3, which has a much cleaner filter than the earlier REV1 and REV2 Prophet-5 synths. Plus the Prophet-6 has a lot more features than any version of the Prophet-5. But the Prophet REV2 and even the Prophet ‘08 can all sound pretty close with the right settings, especially if you add a bit of EQ and reverb. Some folks will obsess over tiny differences in the sound of these synths in isolation, but that should only tell you how similar all those Prophets sound.
If you want the best of both worlds, for the price of a new OB6 keyboard ($3500 USD) you could get a new OB6 desktop ($2400 USD) and a used Prophet '08 keyboard (~$1000 USD). Plus that would give you an extra octave of keys compared to the OB6 or Prophet-6 keyboards.
But before you take the plunge, why not test the sounds with some plugins? Download the e-he REPRO-5 demo version and the free DiscoDSP OB-XD, and see how you compare the “Prophet” and “Oberheim” sounds. Maybe you’ll find that you prefer Oberheim tones after all. You might even be happy with the plugins instead of an expensive piece of hardware.
Thom playing the band’s Dave Smith Instruments Prophet '08 during the recording of Ful Stop (nigelgod).