[review] 3Leaf Audio Groove Regulator (by Bieke)

The 3 Leaf Audio Groove Regulator claims to be one of the most versatile envelope filters on the market today. Its circuit is derived from the infamous and discontinued Lovetone Meatball. The large frequency and dynamic range makes it equally suitable for bass, guitar, keyboards or synths, samplers and general studio use.

Now, the Meatball had a plethora of knobs and switches, interfering with each other, making it a rather complex and hard to dial in pedal. The Groove Regulator attempts to reduce the complexity. For instance, on the Meatball there is a hi, mid, and low switch, whereas the Groove Regulator only has hi and lo. The Groove Regulator also maintained a lot of the same features as the Meatball but makes them more user friendly.

Overall, a very refined and smooth sounding filter. It can go from very thick and juicy to thin and quacky with a few minor adjustments. The down mode is very nice and you can get some really cool vowel type sounds out of it. Again, very Meatballish, even though you can tweak the Meatball a little more for a wider range, longer sweep, deep filtered sounds. But the Groove Regulator is easier to use, is more compact, well laid out, and is an affordable alternative for those who want total control of their sound.

Let us have a look at the controls.

It has four knobs:

  • Sensitivity controls the sensitivity of the filter, should be dialed in lower for high-output instruments or higher for low-output instruments.
  • Attack controls the initial response of the filter. Should be tweaked in conjunction with the decay control.
  • Decay controls the time it takes for the filter to sweep the note. This controls the time it takes for the filter to sweep the note. Higher settings develop long, sweeping envelope sounds, while lower settings develop shorter, more “bubbly” envelope sounds. Decay should be set higher than attack.
  • Intensity controls the intensity of the filter. Functions similar to the tone knob on a guitar. Higher settings will accentuate the treble frequencies; lower settings increase the filter’s warmth.

In summary, the Sensitivity and Intensity controls shape the sound of the filter and the Decay and Attack controls establish the envelope effect. More Decay, the longer the envelope runs.

There are also three two-way toggle switches on the Groove Regulator:

  • Range - Controls the frequency range of the filter, hi or lo. Hi is the classic setting for guitar. Users that want the fattest low-end sound, can flip the switch to the Lo setting. According to the manual, the Lo mode can put out frequencies so thick and juicy that it is possible to blow speakers.
  • Feedback - Controls the resonance of the filter. Dedicated switch for guitar. In case of excessive feedback when using the pedal with overdrives, distortions or fuzzes, flip the switch to the down position. It also makes the envelope effect slightly more subtle.
  • Sweep - Controls the direction of the filter's sweep, up or down. In the UP position, the filter sweeps normally. In the DOWN position, the sweep is reversed. Also has to be used in conjunction with the attack and decay controls.

Effects loop

It also has an effects loop, where external effects could be placed after the trigger section, but before the filter section. This works great with delay in the loop, to get those swooshy echoes, or sweeping repeats. Or you can put a fuzz or an octave in the loop to get those cheesy 70’s synth sounds. If the pedal in the FX loop is left on, it will turn on and off with the Groove Regulator. The FX loop can also be used with external triggers. If you plug your instrument into FX RETURN, then whatever is plugged into the IN jack will trigger the filter. You can use anything as an external trigger. Anything goes.

Let's plug it in!

One might assume that with all these controls and switches, it should be capable of making lots of different sounds. Yes and no, it is an envelope filter after all, a pretty versatile one after all, but as a sound effect, it has its limitations. It does bring the funk, it does great autowah sounds, it can quack and do vowely stuff, it is great for rhythm, can add dynamics to your riffs, it does go from bright and lively to dark and swampy. But it is not as extreme as for instance the Mutron filter, for instance, I could not nail that that classic chewy Mutron sound nor did I hear that typical Q-Tron growl. But I did get a much cleaner and easier to handle filter sound when playing with the Groove Regulator. It is not too sensitive, it does not overload, no volume spikes as well. I think this has to do with the width of decay and range controls being a bit narrower as opposed to that of the Moogerfooger Low Pass Filter, the Lovetone Meatball, the Electro Harmonix Q-Tron or the Mutron III.

It’s not really a tame filter pedal, just not as excessive as the forementioned rivals, which is not necessarily a bad thing. It is much easier to get a good sound out of the Groove Regulator. With its depth and range being slightly narrower, it also becomes a lot easier to tweak it to perfection. Actually, I could not find any bad sounding setting on the Groove Regulator. Only when you abuse the controls and have the attack and decay all the way up, it will start to struggle a little. Actually, I found a blubbery, fast filter wobble sound like that, a sound that I cannot dial in on the Meatball, the Moogerfooger or the Q-Tron.

Build quality is pristine, it is a nice compact size pedal, all the jacks and power supply plug (standard Boss 9V plug) are on the top panel, it has a green status LED, true bypass, all the jacks and controls are circuit mounted, the circuit looks top quality, all housed in a sturdy aluminum enclosure with powdercoat finish, definitely built to last.

3 Leaf Audio are based in Seattle, Washington,pedals are hand made by Spencer Doren and he has released 3 different filter pedals since he started his business in 2008. The Groove Regulator was their first pedal, and you can still pick these up for about 175$.


Subscribe to our newsletter

Also check out Effects Database's social media accounts: