Arturia 3 Compressors You'll Actually Use by Sound-Guy
Arturia - 3 Compressors You'll Actually Use
If you haven’t already seen the announcement, Arturia have introduced a set of three classic compressor/limiters at a very low initial price. If you are sitting on the fence and haven’t tried these, you might just want to fire up your PayPal account and get your order in soon, before the special price offer ends.
Left to right FET-76, VCA-65, and TUBE-STA
The three dynamics processors on offer are the FET-76, an ode to the classic UREI® 1176 FET compressor, the VCA-65 based on the classic DBX® 165A®, and the TUBE-STA based on the rare Gates STA-Level automatic-gain-control amp first used in radio broadcast stations. You can read the full promotional literature on Arturia’s site (Arturia - Overview).
The 1176 is known for it’s very fast attack capability, the 165A for its smooth gain reduction and great treatment of percussion sounds (it even has a peak limiter built in), and the STA-Level for its wonderful transparent (and ‘smooth’) gain control. What you won’t find on the site is results of my testing,and my opinions. So here goes.
As with all Arturia software products you need an account and the ASC (Arturia Software Center) module - you can install the “3 Compressors You'll Actually Use” (3 Comps from now on) to a computer connected to the Internet, or to an offline computer if, like me, you don’t want the interruptions and potential problems of an audio studio that is always online. I found downloading and authorizing was quick and easy.
The 3 Comps are available only as 64 bit plug-ins, but in the usual formats, VST 2.4, VST 3, AAX, AU and NKS, for Windows (7+) and Mac (10.10 and up). They worked perfectly well in a 32 bit DAW with built-in bridging (REAPER) and in my 64 bit Studio One 4.1. Arturia provide a manual for each model compressor, although the intro and legalese are the same in each. But most of pages of each manual provide a thorough explanation of the controls and operation, and describe some history of each unit.
The Really Good Stuff
These emulations look beautiful, and even better, they sound excellent. They represent three very different approaches to compression, and they each add features the originals never had. One of these is a Mix control, providing parallel compression right in the compressors. Another feature on the main panel is a link control - this allows the output level knob to move in the opposite direction of the input gain knob in a rough attempt to keep the output from changing too much as different settings are used. It is not really an auto-makeup gain, but does keep the signal from dropping too much as more compression is used. And neatly, even when linked, the output gain can be changed without affecting the input knob. I found this mode very handy.
However, in addition to the main panel, there is a drop-down “Advanced” panel that really brings in the magic. This supplies an external sidechain feature, with a level control on the external signal (+/- 24 dB), a selection of five to seven detection modes (!), a great filter section with both high-pass and low-pass filters (12 dB/oct), and a Band EQ filter that really got my attention. There is also a “Listen” switch in the Advanced panel that let’s you listen to only the sidechain signal, be it internal or external, which is very helpful if you need to exclude (or emphasize) a specific frequency range, like the kick drum, vocals or cymbals.
The Advanced panel of the FET-76 and VCA-65 includes a “Time Warp” control that provides, at the “Snap” end, look-ahead capability (up to 5 msec), and at the “Loose” end adds some delay to the detection (up to 10 msec). This control is handy to enhance or suppress fast transients. The TUBE-STA has no such function since it always provides a rather relaxed response, as does a real STA-Level.
Back to Detection Modes
While some other compressor emulations I use include a few detection modes, such as linked channels (the signal levels of both input channels are “mixed” in some way and both channels receive the same gain reduction - this is the most common detection mode), dual-mono (the left and right channels are separately detected and processed, so gain reduction may be different for the left and right), and mono (a stereo input is collapsed to mono in the compressor), the 3 Comps add some others. One is “Reversed” where the left channel gain reduction is controlled by the right input level, and vice versa. This may seem strange, but can help expand a stereo image. Each compressor also has “Mid Only” and “Side Only” modes which needs some explanation since the inputs are left and right channels, and there is not an obvious mid/sides mode on the main panel. The 3 Comps can actually decode the input channels to mid-sides for processing, then encode them back to left-right at the output. These modes are accessed by the Advanced Sidechain Control and allow you to emphasize the center or sides with a range of effects to change the stereo imaging.
The VCA-65 has two additional detection/processing modes, Mid>Side and Side>Mid. These modes use the Mid for detection and compress the Side, or use the Side for detection and compress the Mid, respectively. Like the Reverse mode this can affect the spread of the stereo field, but in a somewhat different way.
The FET-76, like its ancestor, uses peak detection, allowing very fast responses. The TUBE-STA, like its inspiration, reacts more to average signal levels, and provides a relaxed response for both attack and release, actually useful for mastering and use on tracks/buses with appropriate sounds. The VCA-65 has a rather different detection scheme than the others - it reacts to the RMS value of the control signal. This makes its response more like human hearing. You can see the FET-76 and TUBE-STA do not have a threshold control, but use an Input gain control to accomplish the levels at which compression starts. The VCA-65 does have a threshold control as well as variable ratios, attack and release times, being the most modern design of the three designs (introduced in the late 1970’s).
What Did I Find?
Each of the three models responds differently to the same audio material. Using both internal and external sidechain ability (some excellent compressors I have lack this) and the mid/sides capability (only a couple other compressor emulations I have provide this), I found little I couldn’t do for controlling dynamics. These units also yield coloration that I expect matches the originals (don’t have any of those to directly compare), with the VCA-65 being the “cleanest” (total harmonic distortion was measured under 0.1% unless very high ratios and fast attack were used - and engaging its peak limiter yielded nice crunchy distortion in the double-digit range). The TUBE-STA is the most colorful (although still under 1% unless the input gain was cranked way up - I was able to get over 25% THD with the input setting at +48 dB!). The FET-76 was in between, but still low on the distortion measurements at about 0.5% max. They all sound analog, as everyone wants these days!
The gain reduction curves vary significantly across the three models, and with different setting as can be seen in the plots below:
FET-76 Transfer Function with 4:1 Ratio and 12:1 Ratio
VCA-65 Transfer Function with 2:1 Ratio and 2:1 Ratio Plus Peak Limiter set to -12 dB
VCA-65 Transfer Function with 6:1 Ratio on left; TUBE-STA Transfer Function with its Program Dependent Ratio on Right
CPU load was moderate - from about 0.6% for the FET-76 to 0.9% for the VCA-65, the TUBE-STA midway between these (measured in REAPER). Latency was low for the TUBE-STA at 32 samples, while the FET-76 and VCA-65 hit 272 samples. This was measured on a PC Audio Labs Rok Box PC (Windows 7 64 Bit, 4-Core Intel i7-4770K, 3.5 GHz, and 16 GB RAM).
Will I Actually Use the 3 Compressors?
No doubt about it! I will use all three for appropriate source material, with the TUBE-STA likely to find itself on a master bus and for mastering. And I like what the VCA-65 can do, both as a compressor and limiter. I’d say if all I had for compression and limiting were these three units, I’d be in very good shape! A compressor set that I will definitely be using.
Very fine sounding units with what appears to be excellent emulations of the classic hardware compressors.
Excellent GUI - looks like the real thing with some very useful additions.
Flexible sidechain controls, and external sidechain capability. Love the Band EQ!
Moderately low CPU load and latency, especially the TUBE-STA.
“Analog” distortion is low unless you push the input hard, especially with the TUBE-STA and using the peak limiter in the VCA-65 (the resulting “crunch” can be very useful).
None that I can figure.
Arturia - Overview