Review: Safe Sound Audio Dynamics Toolbox
A compressor and sub-mixer in the one device? Sounds risky but it’s not.
By Andy Stewart
1 September 2008
The world is finally waking up to parallel compression. And it’s about time. The technique of mixing uncompressed and highly compressed signals together – sometimes known as ‘New York’ compression – has been around for years, of course, but until quite recently it was a relatively obscure process. It’s still relatively esoteric even today: ask any budding engineer or musician what a plug-in is and they’ll have the answer for you in 40 samples; ask them to describe parallel compression and they may not fare so well. It’s a technique ‘best left to the professionals’, some would say, even though it’s actually a relatively simple concept. Certainly, when you reach for a compressor, it’s not instinctively the first approach that springs to mind, however, it’s still one of the most effective. Now, with the release of the new Dynamics Toolbox stereo compressor from Safe Sound Audio, parallel compression is available at the press of a button. No-one need fear parallel compression again.
For anyone who doesn’t know what ‘parallel compression’ really means, simply put, it’s essentially the process by which an audio signal (or group of signals) is mixed together with an often-times heavily compressed split of itself, to create a form of compression that effectively works from the ‘bottom up’ rather than the ‘top down’ (See Parallel Compression below).
PARALLEL UNIVERSE
The technique of compressing a signal ‘in parallel’ requires two ‘versions’ of a given sound, rather than just one. Of these two versions, only one is compressed – typically quite heavily – while the other is left unaffected. Using a conventional analogue routing method, parallel compression takes the ‘second version’ – which is typically created using a bus, auxiliary send or patchbay ‘mult’ – and drives it into a compressor. This compressed signal is then returned in parallel via faders to the mixing console. When recombined with the original uncompressed signal, the ‘amount’ of compression is then simply determined by how much you push those heavily compressed faders back into the mix. The amount is no longer simply determined by how hard you hit your original signal. But more on this later…
SAFE & SOUND
With the Dynamics Toolbox stereo compressor/limiter, this style of parallel compression is managed within the confines of the unit itself, allowing you to do away with all the convoluted sends, fader returns and many of the associated phase issues. It’s a very cool idea; one that will be replicated by countless other products in the near future, I suspect.
The Dynamics Toolbox is effectively a compressor and sub-mixer all in one. Each channel of the device features a rotary ‘Blend’ control that acts in precisely the same way as the aforementioned fader technique, but unlike conventional setups, the Dynamics Toolbox is a doddle to use. It requires no additional patching, it doesn’t tie up valuable faders, buses or auxiliary sends, and quickly removes the mystery and fear that surrounds the technique. In the case of compressing a drumkit, for instance, a ‘parallel split’ of the drums would normally tie up two auxiliary sends (or two buses) and a pair of faders upon the signal’s return into the board. What’s more, care would need to be taken to ensure the signal is returned without flipping left and right accidentally – which may sound unlikely, but you’d be amazed how often this happens. Using the Dynamics Toolbox, all these concerns are bypassed, as it were. It’s simply a case of switching in the unit’s Blend control and mixing the ‘dry’ and ‘wet’ signals together internally, via the single rotary pot.
HOW IT WORKS
When the Blend control is activated (via a backlit switch), a ‘duplicate’ signal is created internally, fed into the unit’s VCA compressor circuit, compressed in the conventional manner – by you the operator – and returned to the output via the Blend control. How much of the compressed signal you mix back into the uncompressed original is entirely up to you: fully ‘wet’ constitutes 100% compressed signal, while ‘dry’ contains none of the compressed signal at all. In this sense, the Blend control behaves exactly like a reverb unit’s ‘mix’ control (as Safe Sound’s wet/dry nomenclature implies). Nothing needs to travel outside the confines of the unit and you don’t need to do anything other than twiddle the knob to taste.
The sound of this internal parallel compression setup is fantastic. The headroom of the Dynamics Toolbox allows you to draw deep and powerful bottom end wallop out of relatively weak and impoverished signals. The Toolbox can sound tough and bombastic one minute – providing your signal with heaps of compression artifacts – and almost invisible the next. This is a very versatile compressor indeed. Not only can you control the dynamics, you can also manipulate the amount of compression artefacts and overall tone of the outcome with the endless combinations of options on hand. If you can’t find some compression settings of interest here, you’re simply not looking!
By way of example, with a mix of mainly compressed signal (the Blend control pointing at about 2 o’clock on the dial), in combination with fast attack and release settings, drums can be made to pump and pound in ways that other compressors only dream of. As you quicken the release and increase the amount of parallel compression, the signal is transformed. But because the original signal is left in pristine condition – unaffected by the actions of the compressor – the combination can be big, clear and powerful. You want bombastic sound? The Dynamics Toolbox can provide you with it in spades, without crushing the life out of the original signal in the process (although this can still be achieved in the conventional manner if you so desire). Utilising parallel compression, the transients of the drums are left intact: our original signal retains all its dynamics while the parallel compression provides us with our wilder, more over-the-top drum sound. It’s then simply up to you how much or how little of this you use. Once you become familiar with the power of this control, I guarantee you’ll be hooked.
The same applies to things like vocals and guitars, where the parallel Blend control allows you to push the levels up and add colour to your signal without destroying its peaks. This is the crux of parallel compression. Sweet distortions and crunchy tone can be applied to the internal side-chain, and blended back in under the overall sound. If you attempted this with a standard compression approach, the first casualties would generally be your peaks, and by the time your distortion was nicely influencing mid and low level signals – that make up the vast majority of your sound – the peaks would be all but destroyed. Using parallel compression, the greater bulk of your signal can be tonally influenced by the action of the compressor without sacrificing peaks and fidelity. This is the essential difference between parallel and conventional compression techniques.
NEED TO KNOW
SAFETY IN VERSATILITY
The Dynamics Toolbox, as the name suggests, is no one-trick pony, that’s for sure. Its controls, however, are presented in a very matter-of-fact, almost purposefully bland way. The overall look of the device seems more reminiscent of a piece of test gear than an esoteric audio device. It’s grey-on-white regalia looks almost out of touch with modern style, and my initial impression was that it seemed better suited to a hospital ward than a studio. But curiously, parked in the rack it looks pretty slick, and at night, when the backlit switches begin to take effect, the unit begins to look more like a bona-fide Christmas decoration than a heart rate monitor.
For a two-rack unit device, there are probably more controls on the Dynamics Toolbox than any other compressor I’ve used before (it even has more buttons and knobs than the Amek 9098!). It’s the ‘100-piece socket set’ of compression. Consequently, some users won’t take kindly to the myriad control features, and I know many prefer simpler 1176-style compressor controls – ‘two knobs and a few switches will suffice, thanks!’. But if you’re one of those who can cope with more than a few controls on your compressors and think you have the patience to understand how they all interact, you’re in for a real treat with the Dynamics Toolbox.
WHAT, NO AIRBAGS?
Beyond the Blend control, the Dynamics Toolbox houses a small army of knobs and switches that can act either fully independently or linked in stereo. There’s a side-chain insert control, featuring sweepable high and low shelving filters (which affects the compressor’s sensitivity to high- or low-end signals). Like every other aspect of the unit, an illuminating switch activates this filter set. But if these aren’t influential enough for your needs, there’s also an ‘Insert’ switch that arms the rear panel balanced 1/4-inch connectors, for inserting an external EQ into the side-chain, for instance. Next to it, the ‘Listen’ switch allows you to monitor this side-chain input and fine-tune your EQ before dropping it back into the signal path to make the compressor more (or less) sensitive to the frequencies you’ve selected. This is a powerful feature, great for de-essing vocals and reducing a compressor’s sensitivity to bottom end signals that can make a compressor pump.
The unit also features comprehensive visual monitoring control via VU meters, and here again, the options are selected via illuminated switches in candy colours of orange and red. There’s a ‘+18dBu’ switch that renders 0VU at +18dBu, which is fantastic for mixing at high output levels, where meters are often pinned and therefore useless. The VUs are also able to show input, output and gain reduction levels, again, all on ‘flavoured’ switches.
It’s the ‘100-piece socket set’ of compression.
COMPRESSION CONTROLS
Both channels of the Toolbox have the usual controls you’d expect on a modern compressor: Ratio, Attack, Release, Threshold and Make-up Gain (or in this case, ‘gmu’ for Gain Make Up). Safe Sound also provides a sophisticated analogue limiter, available post compressor, which offers variable threshold, extremely quick attack times as short as 100µs and low distortion characteristics. There’s an Auto Release function, and a compressor in/out switch (once again, accessed by yet more flavoured switches). But it’s the compressor’s ‘Peakride’ feature that offers yet another component of intrigue.
The Peakride function, as it’s named, enables incoming audio signals to be compressed by a series of three internal compressor side-chains, each with its own set of attack and release times, and quasi ‘floating’ threshold. Safe Sound Audio claims the Peakride function enables the compressor to ride the peak levels of an incoming signal, and adjust itself ‘in a musical way’ to the various sonic peaks arriving at the input. It does this by allowing the three side-chains to work collectively as a kind of sonic shock absorber. The fastest of the three takes care of fast transients, but should the incoming signal exceed the established threshold for any significant period, the other side-chains come to life to progressively lengthen the attack and release times. In short, this effectively ‘liquefies’ the established settings on the front panel, to reduce distortion in the compressor’s derived output signal. To the listener, the result of all this complexity is a very silky, relatively unmolested sound; perhaps the best word to describe it is simply ‘balanced’. The result is a more forgiving style of tracking compressor, perhaps best employed when the source material is unpredictable: during a live performance, broadcast or album tracking. The true effects of this control will only become apparent to users over an extended period of time, I suspect. With only a short period in the company of the Dynamics Toolbox, the Peakride function had me scratching my head somewhat and wondering, ‘is this a case of one too many controls?’ Perhaps someone can write to AT in 12 months or so and tell us how it scrubs up over the longer term.
COMPRESSOR VS CONSOLE
Revisiting the ‘Blend’ control for a moment, one limitation of the Dynamics Toolbox that must be pointed out here is that, while the idea of housing this feature within the compressor is certainly a good one, placing the mixer effectively inside the compressor prevents the original signal differing in any way from the paralleled duplicate. On a console, where the ‘duplicate’ parallel signal can be constructed from an auxiliary send, a custom mix of sounds can be generated that’s wholly dedicated to the compressor’s input. In the case of drums, for instance, a parallel compression signal might be constructed from only some of the individual components present on the console, and these might be mixed at different levels, with different panning etc – in the same way as a headphone mix might be created using aux sends for a performer. So, for instance, a parallel mix of drums might only include kick, snare and overheads, and these might be mixed quite differently to the arrangement of the sounds on the board. Indeed, virtually none of the parallel compression I use when mixing involves an exact replica of an original signal, especially when it comes to drums. Unfortunately, when the compressor generates the parallel compression signal internally, only an identikit of the original signal can be fed to the compression circuit. While this is still a valid and useful tool, it’s nevertheless a limitation.
While we’re on the subject of limitations, for all its versatility and control, none of the rotary pots on the Dynamics Toolbox’s front panel indicate anything beyond maximum or minimum settings, which is quite frustrating at times. Combine this with variable (rather than stepped) controls and the divisions inscribed around the pots become relatively meaningless. This seems a little at odds with Safe Sound Audio’s white, test gear-inspired surgical aesthetic. I was also a little disappointed to discover 1/4-inch jack connectors on the back panel, although earth-lift switches are a handy addition. It’s also unfortunate that the unit lacks a front panel power switch, or one around the back for that matter!
DRAWING SOME PARALLELS
I know I say it regularly in reviews, but the Dynamics Toolbox will be sorely missed when it returns to its rightful owner. Perhaps I’m just addicted to compressors; who knows. But I really am finding it hard to return this unit to its box. It offers a veritable smorgasbord of compression options, some of which aren’t available on any of my other compressors – even though when I count the alternatives I have over 30 of them in the analogue domain alone! I must be insane. What this proves is that A: you can never have too many compressors and B: the Dynamics Toolbox is a unique and versatile device that almost certainly has no equivalent in your rack. Check one out when you can, and provided you don’t get lost in all the controls or mesmerised by all the coloured lights, you’re bound to discover compression options you’ve never encountered before.
RESPONSES