CMajor Releases FREE Pro-54 Browser-Based Synthesizer


Developer CMajor has released the Pro-54 Synthesizer, a faithful port of the classic Native Instruments Pro-53 synth. Surprisingly, it’s not a VST plugin. Instead of your DAW, it operates in a browser window.

I didn’t get into music production during the early days of VST plugins and music software. However, I have a deep respect for companies that have stayed in the game as long as Native Instruments.

That said, I don’t have much nostalgia for instruments like Pro-53. Today’s release is something a bit different and does harken back to the glory days of NI.

Pro-54 is something built entirely for the web browser. The UI certainly looks to have the exact fit and feel as music software from the early 2000s.

As soon as you open the instrument, the interface calls to mind the familiar confines of the Prophet-5. Honestly, I never expected to run such a well-made virtual analog synthesizer right next to my Gmail tab, but life is surprising like that.

You’ve got a pair of oscillators with a square, saw, and triangle available. The triangle is only available on oscillator 2, but that’s well within the norm. The filter is your typical analog-style affair, as are the included ADSR envelopes.

I can’t readily test how the whole thing operates with MIDI, as I don’t know how to route my MIDI controller’s input to my browser. However, you can use your typing keyboard to play some of the notes.

The developers have accomplished something astonishing in porting over an entire full-fledged softsynth circa 2002. I’m not fully tapped into DSP development for web browsers, but I’ve seen far simpler browser instruments make the rounds when they go viral. This one is certainly above and beyond those previous efforts.

I think Pro-54 is a great distraction if you’d like to explore a synth that Native Instruments has long since abandoned. I also appreciate that the synth itself integrates a very solid and decidedly lo-fi delay, so you can generate some surprisingly spacious synth tones.

It won’t stand up to the likes of Softube’s Model 80 or u-he’s Repro-5, but it could make for a fun time for a kid to play around and explore sound synthesis at their leisure. You don’t have to worry about your little one somehow breaking custom binds in your DAW, either.

Pro-54 is readily available for free. You don’t need an account to use it; just click the link and have fun.

This might be the only way to get the Pro-53 sound on a Silicon Mac. You can also view the source code if you’d prefer to fork the project for your own uses.

Check out: Pro-54 (FREE)


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Liam is a producer, mixing engineer, and compressor aficionado. When not mixing, he can be found pretending to play guitar, as he has been doing for the last 20 years.


  1. When I tilted my phone to landscape, the site asked for access to midi devices.
    Multi touch on phone works great (Pixel 8 pro)!

  2. This inspired me to reinstall my Komplete Classics version of Pro-53, but it wouldn’t load up in FL Studio 21 on Windows 10, not even the DXi version

    I have Komplete Classics authorized on my laptop via Native Access, but when installing Pro-53 it from DVD it wants to install the old NI Service Center alongside it.

  3. Mmm. If this trend of doing capable synths in webassembly and HTML5, we’re gonna need a browser as a VST or CLAP plugin… Heh.

  4. Synthie Lauper


    That sounds interesting. I used NI Pro53 a lot in the 32bit days. It was no exact copy, but it was good to fill up spaces.

  5. good! Although it is certainly not as accurate as an emulation, it is definitely a pleasant instrument to play. It may be a good idea to use it in a way that allows you to experience a change in your mood and sometimes get inspired.

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