There's a lot more to Moog's Subsequent 25 than meets the eye...
Back in November 2014, Gordon Reid reviewed the Moog Sub 37. He was impressed by its combination of hands-on, uncompromising design and, of course, the classic Moog sound. At the time it represented a return to form for Moog. Gordon was suitably impressed. In the intervening years the analogue monosynth market has become ever more crowded and Moog's own Grandmother and Matriarch synths have set a new company standard for '70s analogue allure. So can the diminutive Subsequent 25 carve its own place?
The Subsequent 25 is a Subsequent 37 at heart, carefully whittled. But if you read the marketing copy, you'll notice it's presented as an update, or successor, to the Sub Phatty. The visual similarities between the two are undeniable. The Sub Phatty is a two octave monosynth with almost the exact same front–panel layout. It was also reviewed by Gordon, back in June 2013. The Sub Phatty ultimately fathered the Sub 37, which gave way to the Subsequent 37 (see the 'Sub Vs Subsequent' box), which has now sired the Subsequent 25. To put it another way, Moog have taken many of the improvements made in the Subsequent 37 and put them, largely, back into the Sub Phatty. Confused? I'm not surprised, it's a confusing product line, but I'll attempt to clarify it as we go along.
For the purposes of this review I think it easier to see the Subsequent 25 as a trimmer, leaner Subsequent 37. If you want a quick reference of exactly what has changed, again see the 'Sub Vs Subsequent' box. For the most part, they share the same synthesis engine. The obvious differences are a shorter, 25-key keyboard and a dramatic reduction in physical controls to better match the Sub Phatty layout.
Despite the much simpler front panel, more features have been retained than you might think. A lot of lesser used functions remain as what Moog call 'hidden parameters', accessed via a Shift mode. There are two types of hidden parameter. The first can generally be turned on or off, or selected from a small number of options — things like enabling duo mode, pitch-bend ranges, MIDI sync, LFO re-triggering, etc — many of which had dedicated buttons on the Subsequent 37. These require the use of Shift mode and the keybed to select specific options. The second are variable parameters, which are accessed by entering Shift mode and using the front–panel knobs — things like extra envelope parameters, external input level and oscillator beat frequency, which don't have their own dedicated controls anymore. By hiding away a lot of the lesser used functions, Moog have managed to keep a great deal of the Subsequent 37's synthesis engine, whilst reducing the complexity, size and cost.
The Subsequent 37 and 25 are two-note paraphonic analogue monosynths. They both share the same core architecture with dual variable waveform oscillators, a sub-oscillator, mixer section with feedback control, and the classic Moog ladder filter. Both wield dual DAHDSR envelopes and LFO sections, although there is only a single LFO on the Subsequent 25, instead of the dual LFOs on the Subsequent 37. The sequencer and arpeggiator from the Subsequent 37 also didn't make the cut. The paraphonic mode, which Moog call 'Duo mode', allows for the two oscillators to be played independently on the keyboard. Oscillator 2 will track either the highest or lowest note, depending on what preference you have set.
The sloped design, which originated with the Moog Little Phatty and continued through the Sub Phatty...