GS Music Bree6

GS Music have packed seven voices of analogue polyphony into a box that’s as well made as it is small and blue.

I write this almost two years to the day since my review of GS Music’s first ever general release synth, the e7, was published in SOS. That synth was a marvellous thing that channelled oodles of classic Moog energy while also providing a slew of distinctly modern functions. The e7 was, if my research serves me, the first analogue polyphonic synthesizer to be fully designed and manufactured in Argentina. Unless another company has slipped a unit out during the interim (I can’t find evidence of this), the Bree6 is the second.

It’s worth reminding ourselves that the company, founded by one Guido Salaya back in 2014, is still relatively new on the analogue scene yet has adopted what I find an intriguing approach, working with classic architecture on a foundational level but gently pushing it into territories new. You’re unlikely to find any motorised knobs or granular engines here, but you might find the closest thing to an MPE‑controllable Moog Little Phatty you’ve ever used. The 52 x 19cm e7 looks at first glance like a synth from the ’70s, yet under the hood is seven‑voice polyphony with two oscillators per voice, atop a multitimbral mode and digital effects.

The Bree6, by contrast, is a sleek and compact desktop instrument. While by no means simply a scaled‑down version of the e7, it mirrors several of its predecessor’s functions, if occasionally with a scaled‑back feel. It measures a comparatively diminutive 36cm across and sits low on the table, at under 7cm high. Its build quality is nonetheless rugged. In fact, that’s an understatement — it’s without a doubt one of the sturdiest synths of its size I’ve come across, clad in heavy metal and weighing a respectable 1.5kg. Its knobs are decently solid, its buttons are firm, its red LEDs and OLED screen are bright — for me this is key; whether a unit is big or small, the quality of its build should always reflect that of its sound. Suffice to say that box gets a tick in this case.

Streamlined, Optimised

As for the Bree6’s synth architecture, much like the e7 its layout presents few curveballs for even rudimentarily experienced synthesists. Knob‑per‑function is more or less the name of the game here, yet — as with the e7 — the presence of a small OLED screen suggests there’s more to explore below the surface, as well as presenting an array of useful graphical readouts of things like envelope curves, chorus detuning and filter cutoff. If there were two words I’d use to describe the whole package, they would be streamlined and optimised, in that GS Music have done a good job to ensure that plenty can be wrought from relatively few constituent parts. It’s worth saying at this point that I would be more impressed by this if the Bree6’s price was lower than it is: after all, the £1000$1000 ballpark is not a place where one expects to make many concessions in functionality.

It’s probably worth pointing out that the Bree6 is also available in black as well as this charming blue, but whatever size you chose it will measure 360 x 126 x 67mm and weigh 1.5kg.

The oscillator section, for instance, offers just one VCO per voice, with only square or saw wave shapes to choose from. It’s a modest selection, but these wave shapes can be combined, and with the option to modulate the pulse width of the combined wave as well as that of the square wave by itself. A square wave sub‑oscillator is also included, a lovely touch which adds plenty of body to the Bree6’s output without becoming murky. An excellent design feature, courtesy of a screen menu, is that in Unison mode the voices’ oscillator frequencies can be split by any interval, meaning that it’s not dissimilar to using two oscillators per voice. Above all, the oscillators sound fantastic — they’re rock solid in their stability (the manual assures us that the Bree6 needs mere seconds to snap into tune, though there’s still a quick Autotune calibration function if, like me, you’re the sort who needs to triple‑check before going onstage) and really leave little to be desired, even if the wave shape selection feels slim at first.

The Bree6’s four‑pole low‑pass ladder filter is of course derived from the famous Moog design, and doesn’t disappoint in its smoothness. Once again, everything feels well thought out and well deployed here, with the cutoff perfectly tuned to track at Volt‑per‑octave; this of course means that at high, self‑oscillating resonances and with the Keyboard Tracking knob set to full, it can essentially add something like a clipped sine wave into the overall equation for further depth in the synth voice. Next along is the Amplifier section, which aside from the master Volume knob is essentially a means to control the modulation of the VCA by either the LFO or, curiously, keyboard tracking, just as on the filter. This function means that as you ascend (or descend, depending on its setting) the notes on the keyboard or sequencer, the VCA opens up more, which strikes me as being of limited use with the former control method, but a rather brilliant addition in the latter.

Routes & Moves

As I say, the Bree6’s compact form factor comes with excellent build quality; indeed I struggle to think of another analogue polysynth that manages to pack its voices into such a tight and solid package. On the table in my studio, it was only marginally bigger than the neighbouring OP‑1. As such, the aforementioned limitation extends to its I/O, indeed presumably due to the lack of real estate. There are 5‑pin MIDI ports for in, out and thru, left and right audio outputs, a headphones output and a USB‑B port, and that’s it. No external signal input, no CV or sustain inputs. Once again, such limitations usually make for more discerning decision‑making — however, as with any polysynth with generous capacity for expressive playing, I would very much like to have seen room for a sustain pedal at least. Interestingly, the e7 didn’t have a sustain input either, though it did offer three different CV inputs for pitch, filter cutoff and gain. The USB‑B port can’t power the Bree6, but I was happy to find it’s fully isolated — many readers will know how often ground hum rears its ugly head when connecting audio alongside USB ports on instruments like this. It also allows for extensive MIDI implementation, with CC messages for all controls and buttons, not to mention MPE control.

The Bree6 may be small, but it still packs full‑size MIDI in, out and thru sockets, not to mention a USB port for MIDI (and MPE), and stereo audio and headphone outs on quarter‑inch jack sockets.

When it comes to onboard options for modulation and movement, once again many will find themselves on familiar ground with the Bree6, with twin ADSR envelopes (with subtly exponential curves) and a single LFO with variable wave shapes and a rate ranging between 0.10 and 100 Hz. The aforementioned CC implementation is welcome, since I couldn’t but hope for even one other onboard modulation option — a cycle option on one of the envelopes, perhaps, or a second LFO. Perhaps an LFO fade function. But then again, my beloved Moog Little Phatty Stage II only has one LFO, and you don’t hear me complaining about that. Perhaps it’s the OLED screen, which, with my synthesist‑in‑2025 mindset, feels like it should have some kind of sub‑menu with an extra modulation source of some kind. After all, if the Bree6 can accommodate MPE or include something as nifty as a noise gate (which it does), just one other source of movement in the synth voice doesn’t feel like a stretch.

Extra Special Effects

If there is one thing which all but makes up for this, it’s the effects section. Readers familiar with my reviews will know that I’m a fan of quality over quantity when it comes to onboard effects, and those on the Bree6 do not disappoint. Its digital delay just hovers on the right side of gritty, almost BBD‑like but not quite. Excellent. I found that the delay, which can capably be set to incredibly short intervals, became almost a type of modulation source in itself, even resonating like a ring modulator — not so much an additive effect as an inherent part of the synth voice itself.

The chorus is similarly intrinsic to the Bree6’s character, not simply in its ability to impart nostalgic Juno‑esque lushness but also in its capacity for stereo widening and subtle frequency modulation. Used in conjunction with the Detune knob in the Voices Mode section, things suddenly began to get interesting — weird and wonderful — yet still compact and with few discrete parameters. Were my concerns about the singular LFO being allayed before my ears?

Conclusion

Perhaps. The Bree6’s choice of functions is curious at times: some things one might expect to find as standard are not here, for instance a noise generator. Other things, which I would sooner associate with far larger synths, are included; not only in the effects section, but also performance functions like Knob Smoothing, which adds slew to the response time of the knobs for smoother motion. There’s also capacious memory for preset storage — 512 slots to be exact. The Voices Mode section offers more flexibility than I expected: beyond Mono, Unison and Poly there’s Poly Stereo, which distributes voices across the stereo field. If it wasn’t already clear, this used in partnership with the chorus makes for some exceptionally wide and lush sounds, which, with the help of such a rock‑solid analogue ladder filter, could capably pass for the sound of a synth three times the Bree6’s size — and price.

The question that persists in my mind, though, is who exactly is the Bree6 for? Its layout and functionality feel perfectly suited for the novice, but a £1000$1000 synth with no keyboard is unlikely to break into that market easily, particularly not with the likes of the Moog Messenger now in the picture, which has a keyboard and retails for a good couple of hundred dollars less.

It couldn’t be built better, it could hardly have an easier workflow, and most importantly, it couldn’t sound better than it does.

Is it, then, for the more experienced synthesist? Well, it sounds good and it’s certainly portable. As I write this I have a session on location coming up; needless to say, with analogue polyphony called for on the track sheet, I would far rather pop the Bree6 and an Arturia KeyStep in my case than cart my huge Sequential Trigon‑6 all the way to rural Devon. Its MIDI implementation means that if you’re not the software synth type, you’ll very much enjoy it as a USB mainstay in your DAW setup, and this I can easily imagine. The price feels at the upper limit for what you’re getting here, but at the same time it’d be unfair to focus on all the things the Bree6 is not. It couldn’t be built better, it could hardly have an easier workflow, and most importantly, it couldn’t sound better than it does — and I daresay that’s worth paying for.