Starsky Carr Review

Sequential Prophet 10 With LFE

GEOSynth Review

LFE Showing Patch Names for Prophet 6 and OB-6

Top Note Aftertouch for OB6


Sequencer, spread and PWM


LFE and OB6

The LFE is a standalone, hardware modulation expander that supports the Sequential OB-6, Prophet 6, Rev 4 Prophets 5 and 10, Korg Prologue, Nord Wave 2 and Moog Voyager. It uses midi to provide 3 complex global LFOs and a 6-stage envelope – which can also be configured as an 2 to 16-step modulation sequencer – to add considerably more complexity, movement and playability to these amazing synthesizers. The LFE can also control any midi device that can be controlled by midi CC messages.


It also acts as a 4-slot modulation matrix, allowing you to route velocity, key, aftertouch, mod wheel or CV in (optional) to about 50 destinations in the synth (80 with the Nord!)

The LFE can provide polyphonic modulation for the OB-6 and Prophet 6 as these now support MPE, so in this case the LFE generates 21 LFOs and 7 envelope/sequencers.


The LFE reads and displays patch names from the Sequential synths and Prologue. The LFE also displays a Category for each patch. You can easily change categories and you can select the next (or previous) patch in the same category, stepping through all of the Bass patches for example.

LFE Display

Selecting a new patch on the synth makes the LFE automatically recall the same-numbered LFE patch from its memory, so the two have their patches locked together.

LFE Picture

The LFE can generate its own midi clock, both for its own modulators and to control external gear and now includes an arpeggiator.

LFE Front Angled

The LFE supports Poly Chaining using any keyboard as master and any synth as slave.



• Two versions are available, styled to complement the OB-6 and Prophets. Both are functionally identical
• Two 5-pin midi Ins are provided for easy use with master keyboards and complex setups, as well as Out and Thru
• LFO 1 and 2 each have 10 waveforms, with adjustable shapes and can be set to run continuously or for just 1 to 9 cycles
• LFO 3 is adjustable from ramp up, through triangle to ramp down and includes a sample & hold and a clock pattern generator for creating interesting, repeating patterns
• Each of the 3 LFOs can have their starts delayed up to 10 seconds and can be made to fade in over up to 10 seconds
• LFO frequency ranges are approx. 0.06Hz to 40Hz
• The envelope generator has 8 knobs to control 6 stages, for the creation of complex, evolving modulation shapes
• The envelope has two looping modes, as well as normal and one-shot modes
• All LFOs and the envelope / sequencer can individually be synced to the keyboard or to midi clock using any of the clock divisions used by the synth (half note, triplets, dotted etc.) plus a number of slower divisions for generation of very slow evolving modulations
• Key sync can be set to normal or to re-trigger
• Each LFO and env / seq has its own Amount knob which can also be set to negative amounts
• A CV in and CV out port (1/4” or 1/8”) is available as an option. These allow you to control the depth of any of the LFE’s modulators with an external CV signal, and to control external analog gear using the LFE’s modulators and / or the synth’s controllers
• Dedicated Distortion knob for OB-6 users. Prophet 6 users instead have a knob that moves the cutoff frequency of LPF and HPF together and Prophet 5 / 10 players can use this knob as an octave shift.
• Firmware updates can be performed by USB interface
• A 9V or 12V DC 500mA ‘wall wart’ power supply is required, either centre pos or centre neg
• Dimensions: Weight 1.7kg with optional walnut ends. 330 x 212 x 85 mm with walnut ends. 305 x 203 x 85 mm without walnut ends

Quotes from happy customers:

'So far, brilliant! I got it going and started getting some really nice textures with a much greater level of complexity. There’s a lot still to explore - the OB6 really does feel like a new instrument now. You have demonstrated a great deal of thoughtfulness in your design of the LFE, and the improvements are a big step forward from where you started. Thanks again for a great box!' - Andy Burton

'I just wanted to chime in with an unsolicited testimonial that this is a well built, and well conceived product, and absolutely adds new capabilities to the OB6, P6 and beyond. I think if my OB6 and P6 disappeared tomorrow I'd still keep this box, but its integration with those 2 synths of course remains its main selling point.' - Phil Aiken

'I highly recommend this expander! As well it takes these instruments into Xpander territory! And great customer support! The top note aftertouch is very cool. I can almost do Vangelis CS-80 type expression!' - Joe McGinty (Psychedelic Furs)

'The OB6 LFE has been an exceptional addition to the OB 6+6 rig. These are both absolute keepers for me. Every Prophet-6 and OB-6 owner should seriously consider one (or two) of these LF Expanders. They’re very powerful integrated partners with these synths.' - String6theory