While discussing the making of the album "Ghostory," [this article](http://www.sonicscoop.com/2012/02/26/behind-the-release-school-of-seven-bells-recombine-for-ghostory/) explains that Curtis employed "a pair of ‘80’s analog keyboards that provided renewed inspiration. 'I had an Ensoniq ESQ-1, and I got a Roland D-50 just for the synth pads.'"more
There is a list of the used instruments on the "Revolutions" album by Jean-Michel Jarre. Its inside the front cover. The text contains the following instruments (and two choirs): "Roland D50, Roland D550, Fairlight CMI II, Fairlight CMI III, Synthex, AKS, Oscar, EMS Vocoder, Dynacord ADDI, Cristal Baschet, AKAI MPC-60, Emulator, Ensoniq ESQ1, ARP 2600, Kawai K5, Geiss Matrisequencer, Cavagnolo MIDY 20, Elka, AMK 800, Drums, Simmons SDX, Bass, Trumpet, Megaphone, Guitar, Choir." Cd cover can bee seen at http://www.45worlds.com/cdalbum/cd/8370982more
The thing I love about the ESQ-1 is that its a traditional subtractive synth hiding in 80s digital wavetable skin, a wolf in sheep's clothing, that REALLY takes advantages of its digital 'brain'. Once you wrap your head around the user interface you can assign ANY parameter to MIDI note velocity. WHAT?! Yeah. I wish it had a better keyboard, but I tend to use it as a module. I like to play a line into Fruity Loops on a nice weighted key controller being sure to really syncopate my attack and then assign that sequence to a MIDI channel that's commanding the ESQ-1 and dial up a patch where filter cutoff or resonance is controlled by velocity. For extra fun I like to crank the audio out thru an ac30, mic her up and hit record. I really enjoy some of the interesting wavetable snippets that the DCOs on this bad boy generate. Blending, say, the piano snippet with a straditional sine or square is really neat. There's a lot of cool percussive sounds in the liabrary. This thing is capable of a lot, but it just doesn't have the kind of hands on control dance musicians expect, however, once you realize its a PERFORMANCE synth designed for guys who play piano and organ and that the ability to create motion and vary texture in your sounds can be PERFORMANCE DRIVEN you will unlock the keys to the kingdom so to speak. These synths aren't worth spit anymore, I don't know why. Buy one and get playing. Even if you're a mediocre pianist like I am you can always record MIDI data and lock to grid to create insane sounding lines. Also, the DCFs are harsh and squelchy in a totally un-vintage (as in un-moogish) way that reacts really great to analog distortion both tube and solid state. Get over the learning curve and you will be able to make really amazing music with this diamond in the rough. This is another highly underrated synthesizer from the good folks at ensoniq.
The ESQ-1 is what I call the "quiet achiever" of the 80s digital synth market. Yamaha brings out the game-changing DX-7 (replete with that godawful electric piano sound which found its way into far too much radio-friendly tripe) and then about 5 years on, Roland says "Okay, our turn! Cop this" and releases the D-50. Both with their positive and negative points, the DX-7 was probably the most user-unfriendly synth available (one J.M. Jarre reports it as being "a pain in the arse to programme") and the D-50 perhaps tried a little too hard with some new lingo ("Linear arithmatic" "partials" etc) Meanwhile, without any fuss, Ensoniq brings out this absolute charmer. 3 digital oscillators (osc sync, FM, and ring mod available) each with 32 waveforms, some analogue, some sampled. A ton of modulation possibilities with 3 LFOs, 4 6-stage ENV generators, each freely routable to practically any parameter. An analogue resonant filter. Velocity sensitive keyboard. MIDI. A large display with dedicated buttons to access each section and parameter (compared to those other two - easy!) Oh yes, and an 8-track sequencer ... I mean really, we're getting into workstation territory here (minus effects though). What's not to like?
Expressive as any highly coveted VCF poly out there but you can always find it for a few hundred bucks. Programming it, on the other hand, is not too fun. There are thousands of patches floating around the net so if you get one get a librarian app and listen to all of them and you are bound to find something great to use.
In respect to my own use, the ESQ-1 can cover some of the same territory of both DX-7 FX & bells and middle-of-the-road resonant analog pads of synths w/ DCOs such as the JU-06 or Poly 61. While it doesn't sound huge or high fidelity by itself, the ESQ-1 sounds great in a mix and is a great songwriting companion as it covers a ton of territory with an unassuming interface that doesn't distract from building solid progressions and melodies. I don't give it a 5 because it commits the sin of having neither an accessible knobby interface, nor a good MIDI implementation. Useful CC messages are not-existent and the only ways to access a filter|OSC|LFO during performance are the mod wheel and a single "XPARAM" which is the Ensoniq parlance for assigning a single CC message number to a single global internal parameter such as filter frequency or an ASDR level.