Sequential Prophet X/XL

Synth and sample engines polyphonic

$3499.00 / $3899.00

I received my Sequential Prophet X on January 31, 2020. Fast, painless, and a great price from Sweetwater. I was set to get it in 2019, then Dave Smith said a new synth “hopefully will be out in September-ish” [2019, video minute 14:40] with no other details. I wanted to see what this new synth is, before making another Sequential investment. September turned out to be too optimistic, and at the mid-January 2020 NAMM show, Sequential announced the Pro 3 which I have also since purchased after the Prophet X.

I’m trying and failing to stop buying synths until they are out for a year for some firmware maturity, and especially for hardware maturity. The Prophet X is in prime time now however on both counts in my opinion.

Essentially the X and the XL are identical machines, except the XL is larger, and has a 76 key semi-weighted keyboard. The X has a 61 key semi-weighted keyboard. I’m a Sequential Pro 2 owner, so I am very comfortable with the features and controls on this synth. Dave Smith’s feature set and design are near perfect in my opinion. I also have a Waldorf Quantum, so I can see from experience that Sequential would be well advised to put similar touchscreen technology someday on at least an upper-end flagship model. I’m going to guess the market agrees with me, based on an unscientific sampling of Facebook group activity levels.

Clearly, the Sequential Prophet X/XL and Waldorf Quantum are different machines though. They both hit a similar market space and most people in that space want both. Many that can only afford one of them or ponder which one to get first, struggle to decide. It’s a very hard decision to make, I can testify. To condense a complex set of variables into a few, the Prophet X/XLs generally have a warmer sound and the Quantum generally is more digital. Both can go into each other’s territory though. The PXs have an extensive sample library the Quantum can’t touch, and the Quantum has synthesis engines the PXs do not.

With essentially 4 oscillators (2 digital oscillators and 2 sample instruments), the PXs have 8 voice-mode stereo, 16 voice-mode mono, and 32 voice-mode paraphonic with a single oscillator and sample instrument. Halve those in stacked or split modes. Its bi-timbral capabilities are something I look forward to. Be sure to install the v2. or newer OS to get the full voice functionality. The newest OS released is v2. at this writing.

The sample abilities are incredible, plus you can add 50GB of user-imported samples or 3rd-party samples (see the Mapping Utility videos in UO X/XL Samples & Presets YouTube Playlist below). I would recommend that you view Tim Shoebridge’s video The Sequential Prophet X Sample Library for an honest listen to the PX sample library. I agree with him, some of it is amazing, and some is filler… I can’t think of a synth that comes with a more extensive sample library, but it would be nice if there were a librarian app that could manage a larger set of Sequential/8DIO samples. As it is now, yes there are 150GB of Sequential/8DIO samples, but you can’t delete any or substitute other Sequential/8DIO samples, you can only add to the 50GB user area. I understand Sequential can’t delete filler, as it may be incorporated into user patches, but they could allow people to keep unused samples off-synth in an external librarian program and continue to expand the stock sample library as well as add the 8DIO optional cost sample packs to the 150GB area. Just a thought, such is life. If this is what we get, I’ll take it, ha!

The X/XL has a polyphonic sequencer with 64 steps and up to 6 notes per step, with unique sequences for each layer if working in stacked or split voice mode.

Finally, this synth has an incredible effects section, 2 effects per layer, with multiple reverbs, 2 delays (standard and BBD), chorus, phase shifter, flanger, ring mod, vintage rotating speaker, high-pass filter, and distortion.


I will say a few things about the Prophet X. There is something about it I cannot even quantify over features and specifications. It makes me a better keyboard player. It is the synth I practice on and rough out ideas on as well as most often, part of the final production. I am wild crazy about my other synths, but the Prophet X is the synth that is out of the cluster and next to my computer that I tinker with the most. The Prophet X just warms my heart.


Manufacturer’s website

Product support, downloads

Download the newest OS

MIDI System Exclusive (SysEx) messages utilities to update (Windows) (MacOS)

See these pages, for complete lists with links of all known factory and 3rd party sample packs, presets and utilities
Prophet X Presets
Prophet X Samples & Utilities

Facebook user groups

Sequential Prophet X / XL


Sequential Forums


revolutionOSC Sequential Prophet X YouTube Playlist
revolutionOSC Prophet X Patches YouTube Playlist
revolutionOSC Prophet X Music YouTube Playlist

Useful links

Uptdated periodically – Sequential Prophet X or Waldorf Quantum?

Be sure to join the
revolutionOSC Facebook Group

This page is a living document, subject to update and expansion.
Last edited – 4/29/2021
If you have any content you think should be added, or would like to help author gear pages/posts, please leave a comment here or on our Facebook group.

Manufacturer Specifications: click to open/close or jump to comments

Prophet X/XL Specifications

  • 2 multi-sampled stereo instruments per voice with editable sample start, sample end, loop size, and loop center, loop on/off, sample reverse, sample stretch, bit-rate reduction, and sample rate reduction
  • Forward and forward/reverse loop modes
  • 150 GB of factory-installed 16-bit, 48 kHz sampled instruments created by 8Dio
  • 50 GB of additional storage for user-imported samples or 3rd-party sound libraries
  • High-pass and low-pass filter per instrument
  • Instrument 1 and instrument 2 delay as mod destinations
  • 2 digital oscillators per voice with selectable sine, sawtooth, pulse, and supersaw waves. You can vary the shape of any of the waveshapes.
  • Glide (portamento): separate rates per oscillator; (samples can glide in Sample Stretch mode)
  • Hard sync
  • 2 x analog 4-pole resonant low-pass filter per voice
  • Digital high-pass filter in Effects section
  • 4 loopable, five-stage (ADSR plus delay) envelope generators: Filter, VCA, and two assignable
  • Polyphonic step sequencer with up to 64 steps (6 notes per step), and ties and rests.
  • MIDI note output
  • Sequences can be copied between Layer A and Layer B
  • Four-stage (ADSR) envelope generator
  • Velocity modulation of envelope amount
  • 4 LFO’s with key sync, phase offset, and slewing per LFO
  • Five wave shapes: triangle, sawtooth, reverse sawtooth, square, and random (sample and hold)
  • 16-slot modulation matrix
  • 28 sources
  • 92 destinations
  • 11 additional dedicated sources: mod wheel, pressure, velocity, breath controller, footswitch, LFO 1, LFO 2, LFO 3, LFO 4, Env 3, Env 4
  • Fully-featured arpeggiator with up, down, up+down, random, assign modes
  • Selectable note value: 16th note, 8th note triplet, 8th note, dotted 8th note, quarter note
  • One, two, or three octave range
  • Re-latching arpeggiation
  • Note repeat
  • Beat sync
  • MIDI note output
  • 64 preset alternative tunings
  • Additional alternative tunings can be imported via SysEx
  • 2 digital effects on each layer
  • Stereo delay, BBD delay, chorus, flanger, phaser, ring mod, vintage rotating speaker, distortion, high-pass filter, spring reverb, room reverb, hall reverb, super plate reverb
  • Master clock with tap tempo
  • BPM control and display
  • MIDI clock sync
  • Prophet X: Full-sized, semi-weighted, 61-key 5-octave keyboard with velocity and channel (mono) aftertouch
  • Prophet XL: Full-sized, semi-weighted, 76-key, Fatar TP/8 keyboard with velocity and channel (mono) aftertouch
  • Backlit pitch and mod wheels
  • Spring-loaded pitch wheel with selectable range per program (1 to 12 semitones up and down)
  • Transpose controls for an 8-octave range
  • Hold switch latches held notes on
  • Polyphonic glide (portamento)
  • Unison (monophonic) mode with configurable voice count
  • 512 Factory Programs (4 banks of 128), 512 Optional Programs, and 512 fully editable User Programs with 2 layers (2 separate sounds) in each Program
  • MIDI In, Out, Thru
  • Sample import jack for USB Stick
  • Main stereo audio output: 2 x 1/4″ phone (TS, unbalanced)
  • Output B stereo audio output: 2 x 1/4″ phone (TS, unbalanced)
  • Pedal/CV: responds to expression pedals or control voltages ranging from 0 to 5 VDC (protected against higher or negative voltages.
  • Volume: responds to expression pedals or control voltages ranging from 0 to 5 VDC (protected against higher or negative voltages.
  • Sustain pedal input: accepts normally on or normally off momentary footswitch.
  • Sequencer: accepts normally on or normally off momentary footswitch to trigger sequencer playback.
  • Headphone output: 1/4″ stereo phone jack.
  • IEC AC power inlet for internal power supply
  • Operates worldwide on voltages between 100 and 240 volts at 50 to 60 Hz
  • Power consumption: 25 watts maximum
  • Dimensions: 38.44″ L x 13.53″ W x 4.13″ H (97.6 cm L x 34.3 cm W x 10.9 cm H)
  • Weight: 24 lbs
  • Dimensions: 46.8″ L x 15.5″ W x 4.1″ H (118.7 cm L x 39.4 cm W x 10.4 cm H)
  • Weight: 33.2 lbs (15 kg)