GForce Software M-Tron Pro IV review

With an update to an established icon, GForce makes the case for the tape-based arts (albeit in software form)

  • £150
  • €196
  • $190
GForce Software M-Tron Pro IV
(Image: © GForce Software)

MusicRadar Verdict

A case of an excellent existing plugin that’s been improved through a lot of small enhancements to improve it hugely.


  • +

    Engaging and easy-to-use interface.

  • +

    Packed full of excellent sampled content – some very familiar!

  • +

    Matrix Reverb is a huge improvement.

  • +

    Even the basic enhancements are useful.


  • -

    Worth considering the ‘Complete’ bundle – which costs more!

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GForce Software M-Tron Pro IV: What is it?

The word ‘legendary’ is far too easily thrown around these days, especially with regard to vintage synthesizers. But the Mellotron has no issues with holding that legendary status. It’s regarded as the first useable sampler, employing analogue tapes instead of digital tech! 

Based on the M400, the M-Tron Pro from GForce Software has become as iconic in software form as the original instrument. Now in its version IV guise, this update maintains all of the classic elements, while adding new patches, samples and a host of new features.

GForce Software M-Tron Pro IV

(Image credit: GForce Software)

GForce Software M-Tron Pro IV: Performance and verdict

Anyone updating will feel instantly at home, as the GUI maintains the same operational approach. 

Also consider...

Arturia Mellotron V

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UVI Mello
The perfect production-ready package, that operates from within UVI’s own Workstation plugin.

There are two layers, described as A and B, which host a different sample. Each layer can exploit its own set of edited parameters, or you can use the Link button, to quickly and easily apply any edits to both layers. Ported from previous versions, editable parameters include a resonant filter, which has now been enhanced to offer low, high and band-pass modes, and two ADSR envelope generators which are hardwired to the filter and amplifier.

From here on, there are a host of new features which augment control. Firstly, the initial samples/tape banks, receive a boost. The basic M-Tron Pro IV suite ships with over 3.5GB of factory samples, which includes more than 800 patches, curated by programmers and recording artists. There are some wonderful surprises here, such as the Isolation Choirs. Apart from literal choirs en masse, there are also samples, demonstrating the vocal talents of the likes of Matt Berry and Alex Ball. 

Literal choirs aside, there are also samples with vocals from the likes of Matt Berry and Alex Ball

One possible criticism that could be levelled at previous versions of M-Tron is that the plugin may sound a little too good, depending on the quality of the originally sampled tapes. The newly enhanced Tape section now offers Wow and Flutter controls, complete with a level of instability that can be applied to taste. The rate of wow and flutter can also be controlled, providing a degree of consistent degradation, and can be taken to relative extremes. The half-speed and reverse functions are also great for extending the tape notion further.

The LFO section has also received an update, and has now been equipped with five wave-shapes, which can be further controlled using smoothing and fade-in. When coupled with the existing rate and depth control, there is now capacity for taking M-Tron to new places, through the ability to set the LFO destination to pitch, filter, pan or level. 

New edition additions

The instrument GUI is now fully resizeable, which is a nice touch and it is also possible to extend the bottom sample range down to a low C. This extends the lower sample, proving to be both useful and creative. At the playing level, M-Tron IV also responds to polyphonic aftertouch and velocity, which is set within the performance area of the plugin. 

The output of the M-Tron Pro IV is still routed through a series of effects, but with new additions. We now have an amplifier simulator, adding warmth and saturation, along with an ensemble effect. However, the biggest enhancement relates to the New Matrix Reverb, which provides a beautiful back-end reverb, extending to black-hole proportions.

GForce Software M-Tron Pro IV

(Image credit: GForce Software)

Changing tapes

The quality of M-Tron IV Pro continues to sound reassuringly expensive. The initial samples themselves sound stunningly beautiful, even without editing and effect application. The diversity and choice across the samples remains incredibly high, allowing the use of the substantial patch library, or ability to get very creative from the partial level upwards. 

The included additions and improvements make this a very worthwhile upgrade, while anyone jumping in for the first time will doubtless get lost in so many classic sounds, which sound incredibly familiar.

MusicRadar verdict: A case of an excellent existing plugin that’s been improved through a lot of small enhancements to improve it hugely.

GForce Software M-Tron Pro IV: The web says

"Probably the leading Mellotron soft synth — now much improved and even more encompassing than before."
Sound On Sound

GForce Software M-Tron Pro IV: Hands-on demos

GForce Software

Nu-Trix The Synth Guy

The Sampleist

Synth Anatomy

GForce Software M-Tron Pro IV: Specifications

  • macOS 10.13 or above. Intel & Apple Silicon Native, Standalone Application, AudioUnit, AAX, VST2, VST3.
  • Windows 7 and above. 2GHz CPU with 2GB RAM.  Standalone Application, VST, VST3, AAX.
  • CONTACT: GForce Software