There's gear that does its job in technically proficient and sometimes even colorful ways. In the capable hands of skilled producers and engineers, the gear brings to life the instruments and sounds that run through its electronic pathways. And then there's gear that is musical in its own right — gear that encourages listening, has a vast array of tonal shades, and is multi-functional and perhaps endless in application — bringing you to the heart of why we exist as music workers. You'd be hard pressed to find any top-notch engineer that doesn't get excited about a new possibility or advancement in technology that can help us reach that place. Aren't we all on that quest? Gregory Scott from Kush Audio is one such seeker. His designs are consistently cutting edge instead of retreads — each of his pieces a new concept that will inevitably be considered a classic.

At last year's AES Convention in Los Angeles, I was fortunate enough to be manning the Tape Op booth right next to Kush Audio's. I asked Gregory Scott what was new, and he gave me a demo of the Tweaker that left me drooling like Ed Roth's Rat Fink hot-rod cartoon character. I knew then that I had to have one of my own.

The Kush Audio Tweaker is a single-channel VCA dynamics processor. You may have already heard musings about how this device is a "Swiss Army Knife." When I'm introduced to a "do it all" box, I get a little anxious thinking about the ramp-up required to get to where I feel comfortable using it on a client's record. I really love simple tools that do a specific task well. Truth be told, the Tweaker does take some time to get your head around. It has a very thoughtful and rich set of controls for dialing in a vast array of tones and compression characters. The example "presets" hint at the breadth of the unit's capabilities, making reference to a number of highly desirable compressors — API 2500, Valley People Dyna-mite, and UREI LA-2A, for example. But I hesitate to even call these presets emulations for fear of belittling the scope and power of this processor. Consider them starting places in the vein of some boxes we love and have heard on countless recordings.

The Tweaker is not your typical VCA compressor. Many current offerings on the market are based around integrated VCA chips manufactured by THAT Corporation. You will find THAT chips in the designs of dbx, SSL, API, Rupert Neve Designs, Symetrix, and many other pro audio companies. The Tweaker utilizes its own VCA circuit that, as Gregory Scott puts it, allows it to "artfully misbehave."

Artfully misbehave — I love this. And it really speaks to what I love about the Tweaker. Imagine having a beautifully-designed boutique compressor that's been circuit-bent. Instead of a Speak & Spell made into a fun electronic noise machine, the Tweaker is a high-end piece of audio equipment transformed into a multi-functional music-making tool. Sure, the Batmobile is functional transportation, but depending on which reboot it appears in, it also flies, shoots projectiles, travels underwater, and foils masked evil-villain clowns.

The Tweaker's controls are divided into three sections that correspond to the audio, side-chain, and detector paths. Although I could easily write a short novel on each of these sections, I have a word-count limit, so I will limit myself to elaborating on a few key features that I find especially useful and exciting.

One of the fantastic features of the Tweaker is the Drive control, the first knob in the audio path section. It's useful for adjusting signal clarity and impact when I need an element to be more present in a mix — without resorting to EQ — as well as for grit and excitement. For example, sometimes a clean electric guitar can sound just fine when isolated, but when placed in a mix, it loses some of its magic. I was able to use the Tweaker to seat such a track in its mix while giving it some life and teeth. There is a full range of tones that can be achieved with Drive, from gentle presence to quite aggressive tube-amp-like sound. Even a lackluster track at minimal to no gain reduction can benefit from the Tweaker's serious tone-shaping. When you want the filth, you can have it, and when you don't, the Tweaker operates at a very clean 0.003% THD. Gregory Scott explained to me the unique workings of his Drive control:

"After a bunch of random hacking, I ended up having the Drive circuit cook the levels inside the VCA itself, rather than simply overdriving the input stage or the output stage. Compression, by definition, lowers the level of the VCA. If the VCA is distorting because it's overdriven, compression momentarily cleans that up. So for example, if you're smacking a drum bus, as the Tweaker lays into the transients, the distortion backs off, and as compression is released, the dirt is restored. The net effect is that you can add a lot of filth to a signal, but during heavy compression, the transients still come pounding thru. It's the best of both worlds — heavy dirt with strongly defined transients! Because the distortion is in the VCA, the grime comes primarily from the super-matched transistors, plus a bit of vintage amp grind as well."

Also in the audio path section is the Mix knob, which lets you blend the unaffected signal with the post-VCA compressed signal for parallel compression.

Moving on, the side-chain path section includes knobs labeled Threshold, Contour, and Sidechain Shaper. Threshold is straightforward. It sets the level at which compression will begin — more compression to the right, less to the left. Sidechain Shaper chooses from an array of filters that operate on the signal that controls the detector (but not on the main audio path): 60 Hz HPF, 300 Hz HPF, Treble Smash, Edge Contouring, and XLR insert. The latter allows you to patch in external side-chain processing of your choosing.

A standout from Gregory's demo at AES was altering the feel of a drum groove by utilizing Edge Contouring on a stereo drum bus. Edge Contouring lets you focus the compression on a specific frequency area. Focusing on the low end by turning Contour all the way to the left, which makes the kick all but disappear; opening up the attack until the hi-hat sneaks through; then setting the Mix control at 60/40 so that the original uncompressed signal is parallel with the compressed signal, bringing back the kick — you can radically alter the groove from a heavy downbeat feel to an emphasis on the upbeat. Once your desired feel is achieved, start playing with the release control, which gives further nuanced control over the groove. When combining the original groove with the compressed parallel signal with different elements emphasized, you can create fantastic motion to a drum track.

Treble Smash is also worth describing. It does awesome silky things to the top end of bright percussion tracks, and it adds great tape-like compression character to acoustic guitars. I even use it on vocals when I want things bright and present but not harsh. It also adds a nice thickness and weight to bright elements that scream "ANALOG!" 3 kHz sunburn? Not anymore. I have said before that I often go for compression instead of EQ to tame over-brightness, and the Tweaker may just do it better than any compressor I have encountered. This is a fantastic feature that I will return to again and again.

The last section is for the detector path. Attack ranges from 20 μs to 70 ms. Release can be set for single or dual-stage operation (think LA-2A), and it ranges from 20 μs to 500 ms in single, or 500-7500 ms in dual. These may look like the standard knobs found on most compressors, but on the Tweaker, they are powerful controls for shaping transients, controlling energy, and affecting sonic texture in musical ways. Curve links ratio and knee into one control — a low 2:1 ratio with a soft knee, up to a high 30:1 ratio with hard knee limiting.

All knobs are detented for easy recall, but importantly, none of them are labeled with numbers. I asked Gregory Scott for his thoughts behind this design choice:

"It forces you to listen to what's going on — to shed your expectations of what you're going to hear. Engineers love numbers; I respect that, and at the same time, I don't share in the obsession. I generally find them distracting. Actually, I find almost any use of my eyes to be a distraction when working with sound. I mix in almost total darkness; I can hear better that way, and I feel the music more deeply. When tweezing the UBK Fatso, I learned that, yes, compressors have individual controls for attack, release, ratio, and threshold, but those apparently-discrete parameters are actually interactive. More so on some compressors, less so on others; but generally when you set an attack time, that time will change as other parameters are adjusted. Ratio often affects threshold as well as attack, and so on. Another thing I discovered is that there's actually no universally agreed-upon definition of what attack time really is, and it's a slippery animal under the best of circumstances. The whole 'set the knob here, and the attack time will be this' — it's not always true, and it's not clear what that means. Couple that with my own general lack of interest in the specs, and you get what you see — a compressor with no clearly-defined parameter ranges. You know what you need to know — left is faster, right is slower."

When using the Tweaker, I was more engaged with the sound because I indeed was forced to listen as I moved through the interactions between the various functions, instead of relying on old habits. Beyond familiarizing myself with the abilities of this box, it was a re-engagement exercise and invaluable lesson in listening. Once familiar with the specialized functions of the Tweaker, I was enamored with the array of sonic possibilities. From straight-up clean, utility gain reduction, to obliterated tonal bliss — and everything in-between — the Tweaker was up to the task.

The Tweaker sports a tri-function LED meter that displays input, output, and gain reduction all simultaneously. It too is free of any actual numbers, but it relies on color segments of green, yellow, and red. If you can read a traffic light, you are good. In the appropriate situation, this thing sounds pretty great well into the red, so go ahead and run a red light once in a while.

Since I was sent two Tweaker compressors for review, I used them in a variety of situations while tracking and mixing a record for Los Angeles-based artist Sunday Lane. After a healthy workout on the drums, I was convinced I would never use them anywhere else. They were simply killer, and the sonic options were thrilling, if not a tad overwhelming. So many choices! From blown-out to super-clean, beautifully pumping in time with the groove to minimal compression but with loads of grit — I was in heaven. There was not a vibe I was unable to achieve with the Tweaker.

When I tried the Tweaker on vocals, I fell in love with the locked-into-place creamy goodness. I started with the recommended "LA-2A" settings and made adjustments from there to suit my mix. It did a great job of setting the vocal in place with just a few dB of reduction, but the real benefit was the tonal shaping. All the clarity remained, but a lovely warmth was imparted to the top end. In finding the sweet spot, I traversed the spectrum of spitty and in your face, to very clean subtle compression. This box would clearly be a great choice for any number of vocal duties, from lead, to grouped, and to collectively compressed backgrounds. (Hmm, so now I need three of these things.)

On a bass track, I also started here with a generally "LA-2A" setting and adjusted accordingly. The Tweaker performed beautifully, with plenty of room to dial in an attack and release that got the bass feeling nicely slotted. Again, the Drive feature was a godsend in terms of tone. Taking a clean DI bass signal and running it through the Tweaker with a healthy dose of Drive resulted in a great amp-like sound that was full of life. (Boy, it'd sure be nice to have four of these.)

Beyond using the Tweaker for its many compression characters, I started leaning on it also for its ability to impart tone, edge, warmth, and general vibe to sources. As mentioned above, using the Tweaker even at minimal to zero gain reduction showing on the meters, things just sounded better running through the box.

There is simply no way that I could dig into and fully explore the full depth of every feature on the Tweaker in the time I have had it thus far. In fact, the more I use it, the deeper the well becomes. For transparent compression and limiting tasks, to incredible tone-shaping and motion-generation capabilities, the Tweaker is simply one of the most radical and versatile compressors I have ever laid hands on. Believe the hype.

Tape Op is a bi-monthly magazine devoted to the art of record making.

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