Sequential Prophet X & XL

Synth and sample engines polyphonic

Sequential Prophet X & XL $3499.00 / $3899.00

October 21, 2021 Update: The Prophet XL appears to be discontinued. It is no longer on Sequential’s price list or Sweetwater’s site. Rumor has it the Prophet X may be discontinued soon as well. In my mind, the Prophet X/XL will go down as perhaps the #1 Sequential marketing screw-up, since clearly the synth itself is its best ever made to date.

In my opinion, the Sequential Prophet X & XL are the best polyphonic synthesizers that Sequential has ever made to date. See my comments expanding on this statement in the summary section below.

I received my Sequential Prophet X on January 31, 2020. Fast, painless, and a discounted 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 would be, before making another Sequential investment. September turned out to be too optimistic, and at the mid-January 2020 NAMM show, the Sequential Pro 3 was announced, so I went ahead and purchased the Prophet X. I am so glad I did, it has become my favorite synthesizer.

Essentially the X and the XL are identical machines, except the XL is larger, and has a 76 key weighted keyboard. The X has a 61 key semi-weighted keyboard. As a Sequential Pro 2 owner at that time, I was very comfortable with the features and controls on this synth from the get go. Dave Smith’s feature set and design are near perfect in my opinion.

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. 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 Prophet X low-pass filter is yet another beautiful Sequential filter, but it is important to note that you can bypass it on sampled instruments that may already be well filtered. Doing this will give you 16 stereo voices which are extremely useful for instruments like pianos. Pianos are probably the last things on many synth purchasers minds, but everyone walks away enamored of the Prophet X pianos… Just warning you, ha!

The digital oscillators are like the Prophet 12 or Pro 2, and have sine, sawtooth, pulse, and supersaw waves. Very good, but the more you understand the sample instruments, the less you will use them. The real stars of this show are the sample instruments.

The sample instruments are incredible, plus you can add 50GB of user-imported or 3rd-party samples. 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 generally, some of it is amazing, and some is filler… However this can be subjective. For instance, I love the variety of noise and racket sounds, which can also make some great mod sources, but not everyone does or doesn’t understand yet how useful to sound design these odd tidbits can be.

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 factory Sequential/8DIO samples, but you can’t delete any or substitute other add-on Sequential/8DIO samples in that factory space, you can only add to the 50GB user/add-on area. I understand Sequential can’t delete what some people perceive as filler, as it could be incorporated into user patches, but they could allow people to make their own choices and 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 what we have now is all we get and it probably is, I’ll take it anyway, 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.


Like I said at the beginning of this page, the Sequential Prophet X/XL is the best polyphonic synthesizer that Sequential has ever made to date. It would appear to be the unloved child of Sequential line though. 8DIO the supplier for the onboard samples has never fully delivered on the promise to continue developing sample sets and sample utilities for the Prophet X/XL.

I can only guess that perhaps Sequential’s degrading over time relationship with 8DIO prevented Sequential from putting the necessary pieces in place to properly market the Prophet X/XL and fuel greater sales. I believe that adding a lower cost desktop version along with proper demonstration & real sound design tutorial videos for specifically the sample instruments would have completely changed things.

The good news is that bad news doesn’t matter. Here’s the real skinny. The sample instruments are to die for, and the real power in them comes alive with your own custom curated sample sets added to the stock sample sets. The Prophet X/XL comes with quite a bit of incredible sample sets, but you do need more. The full potential of this powerful and amazing sounding synth comes with sample sets that you add or create, and not with just 8DIO sample sets. The 8DIO sample utility is junk, don’t waste your time with it. Use PXToolkit or even better use SampleRobot 6.5 Pro to create sample sets.

I will say a few more things about the Prophet X. There is something about it I cannot even quantify over features, specifications and the brilliant sample instruments. 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 in the prime spot, front and center. 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 patches, sample packs, and utilities
Prophet X Patches & Samples
Prophet X Utilities

Facebook user groups

Sequential Prophet X / XL


Sequential Prophet X Forum Prophet X Forum


Yehuda Rothschild Sequential Prophet X YouTube Playlist

Yehuda Rothschild Prophet X Patches YouTube Playlist

Yehuda Rothschild Prophet X Music YouTube Playlist

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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)