Source Audio C4 Synth review

The One Series delivers a heavily editable synth pedal with 128 user presets and a lot of musical potential

Source Audio C4 Synth
(Image: © Future / Philip Barker)

Guitar World Verdict

A compact and comprehensive source of synth sounds and textures.


  • +

    Cool synth sounds with excellent tracking.

  • +

    Deep editing via app.

  • +

    128 programmable presets.


  • -

    Not much, but as with any synth pedal, watch your technique.

You can trust Guitar World Our expert reviewers spend hours testing and comparing guitar products so you can choose the best for you. Find out more about how we test.

Source Audio's One Series pedals can be run in stereo and mono, and share a number of features. With 128 onboard preset slots, these digital stompboxes are hugely powerful, and when used with the Neuro graphical editing and librarian software – a mobile app for all iOS and Android devices (cabled connection) and a desktop version for Mac and Windows – you are offered comprehensive control of the effect.

Here we are going to look at the C4 Synth Pedal. Like the others in the series – such as the Source Audio EQ2 Programmable EQ – there's a Control Input jack for the Source Audio Dual Expression Pedal and a USB port. You'll want that editing software close at hand to allow you to adjust editing parameters, stereo routing options and advanced EQ control, and of course to manage your presets.

Thank you for reading 5 articles this month**

Join now for unlimited access

US pricing $3.99 per month or $39.00 per year

UK pricing £2.99 per month or £29.00 per year 

Europe pricing €3.49 per month or €34.00 per year

*Read 5 free articles per month without a subscription

Join now for unlimited access

Prices from £2.99/$3.99/€3.49

Trevor Curwen

Trevor Curwen has played guitar for several decades – he's also mimed it on the UK's Top of the Pops. Much of his working life, though, has been spent behind the mixing desk, during which time he has built up a solid collection of the guitars, amps and pedals needed to cover just about any studio session. He writes pedal reviews for Guitarist and has contributed to Total Guitar, MusicRadar and Future Music among others.