Acme Audio Opticom XLA-3 Compressor

Posted on Posted in Compressors, Plugin Reviews, Saturation/Colour

BrainworxAcme Opticom XLA3

This little gem is a new release from the brilliant brainworx stable, part of Plugin Alliance, the home of some very classy software.

The high end hardware Acme Audio Opticom XLA-3 optro compressor limiter this plugin models is an all valve (tube) unit, as described on the Acme website:

“The opticom xla-3 is an all-tube optical limiter inspired by the classic Teletronix LA2A. Loving the la2a’s smooth natural compression characteristics but seeking to improve upon its single compression speed inspired us to develop the xla-3. The heart of the XLA-3 is a unique triple optoelectronic circuit that combines the best characteristics of 3 separate compression curves into a single unit. The result: a high-speed optical limiter with tones that range from ‘clean’ to ‘harmonically rich’ to ‘dirty.”

While the hardware is a mono unit, the plugin can run in stereo if desired. One feature that I like is the output (makeup) gain knob can be double clicked (labelled Pull Unlink) to unlink the channels in stereo mode. This can sometimes be a great way to add perceived depth to the stereo field. The input gain knob can also be double clicked to pad the input by 15dB. In the hardware, these are push/pull knobs. The shadowing under the knobs changes to show the setting. The appearance of the shadow effect is pretty subtle and takes a while to get used to, although it’s easy to hear the effect of the 15dB pad.

The main advantage of this unit, as Acme themselves have said, is the ability to dial in three different response times. The famous LA2A has just one fixed (fairly slow) time constant.

The manual says that distortion is increased with response time, which is true. This is heard as extra “attitude” or energy, which is a great feature in a dynamics plugin, especially on drums and the like. The switch may look familiar to guitar players – it’s supposed to be a Fender Telecaster® pickup selector switch. Set to “slow” on a snare drum, the transient punch of the stick hitting the skin comes through well, while setting the response time faster adds crunch, crush and energy, all totally dependent, of course, on the input gain setting and the track itself.

On the left there is a gain meter which can be switched to read input or output and below the meter the calibration button works as an additional output gain trim. Very neat.

As the input gain is cranked. the fixed threshold compression circuit is driven harder, as well as the valve preamp stage, 1176 style. (See the Stillwell Rocket review for more on the 1176.)

On the right hand side is the gain reduction meter and the “calibration button” under this meter works as a very handy dry/wet mix control, enabling parallel compression. This is not available on the original hardware and is an excellent feature. On the right of the meter is a 3 way switch knob labelled “Amp/ Out/ In”. The default setting is “In” and this switches in the whole circuit for normal compression and “leveling” duties. The centre position, “Out”, is basically the bypass setting, while the “Amp” setting disconnects the compression circuitry, leaving the amplifier stage in all it’s glory. This is a favourite alternative setting for many engineers, as the amp section sounds wonderful and can be driven by the input gain to produce subtle to strong saturation. This always sounds great, because the all valve (tube) circuit produces pleasing even order harmonics that (naturally) increase with the input gain. These harmonics add the effect of running the signal through real analogue hardware. This feature has a wonderful effect on vocals, acoustic and electric guitars, basses, percussion and whole mixes, adding clarity, warmth or definition. The Dry/Wet mix knob is also extremely useful here, allowing the user to blend in just the right amount of magic. This is not just another saturation plugin, this is the Numero Uno!

It even has a “noise” knob. Says the manual: “Noise Level: continuous from -120 to -60dB (default -90dB) This parameter is not include in the original hardware. The original level from the Hardware unit is at -84dB. Turning the knob to -120dB turns off the noise floor altogether.”

There is also another on/off bypass switch on the right with a very big red light. Indispensable.

This is not a cheap plugin, coming in at $299USD*, but, if you can afford to splash out for it, you’ll fall in love. This baby completely transformed a project I was working on from “that’s great” to “wow!” There are now quite a few pros using this on the master bus, sub masters and many channels in a mix, as a clean compressor/limiter, raunchy compressor/limiter, warming device, saturation device, character plugin, coffee maker (well, maybe not the last one, but you get my drift.)

It’s also pretty easy on cpu resources, so you can use it all over your project.

Can’t live without it.

5 Stars.

For the best YouTube review and demonstration of the Opticom so far, check out Pete’s from