Acme Audio Opticom XLA-3 Native Plugin by Tommy Zai
The Acme Opticom XLA-3 from Plugin Alliance is a stunning optoelectric leveling amplifier plugin that serves as a limiter and/or tone box. It is the software version of Acme Audio's high-end hardware unit that was originally inspired by the industry renowned Teletronix LA-2A, circa 1960s. The Acme hardware unit has become a modern classic, featuring an all-tube design that delivers a smooth natural compression. From what I’ve heard from reliable sources, the XLA-3 plugin looks, feels (with a bit of imagination), and sounds spot on.
WHAT IS A LEVELING AMPLIFIER?
According to Barry Rudolph, “The leveling amplifier is a compressor with a medium attack time, a medium to slow release time, a high ratio, and a low threshold.” As the name suggests, the general purpose for a leveler is to help maintain a smoother gain reduction signal. Without getting into a debate about the so-called loudness wars, let me simply say that this kind of compression raises the average loudness of audio by bringing up the softer stuff. The reason for the slow release time is to prevent or at least reduce a pumping effect of the compressor rapidly engaging in and out.
The purchase, download, install, and authorization process is simple. There are no dongles of any kind. Upon launching, user will notice a GUI that is military green and very retro-looking with old-style analog control knobs, VU meters, etc. It reminds me of the Willys Jeep my mom used to drive (a long story). The interface is simple, straightforward, and extremely easy to navigate. It has an in/out meter switch/output trim with meter, input gain dial, three-position response toggle switch (fast, normal, slow) that affects attack and recovery, output gain dial/dry-wet mix, Amp mode (a pure gain stage), Dynamics Out (compressor bypass), Dynamics In (compressor in-circuit, power switch and corresponding light. The plugin will show up in either stereo or mono and includes the channel link feature on the Output knob (by ‘pulling’ it with a double click), but no actual separate stereo control set. That’s all! Hence, the learning curve is shallow. The Opticom XLA-3 is the absolute definition of a device that is simple, yet powerful.
THREE MAIN CONTROLS (modified from the original XLA-3 Hardware manual)
1. The Input Gain control allows for adjustment of the input signal strength applied across the fixed limiter threshold. Higher settings will enable the input signal to drive the limiter harder, yielding a stronger compression (indicated by the input/output meter). Users can pull-out the virtual knob for a -15 dB pad.
2. The Response selector switch is the “backbone of the unit.” It determines the attack, release, and overall color. It has three positions: Slow, Normal, and Fast. This provides a means of altering the limiting characteristics in a way that enhances versatility and flexibility. The appropriate selection is primarily dependent upon the frequency of the signal (or blend of frequencies) to be limited, the total amount of limiting, and the final sound texture desired. I read a review of the hardware unit that claimed the lever switch design was “apparently pinched from a Fender Telecaster.” It’s all about borrowing the cool stuff, isn’t it?
(1) Slow - fairly transparent and clean, but with nice warmth. Smooth dynamic control with a high compression ratio that creates a slight brickwall limiter effect that almost completely prevents any additional gain above the threshold. Recovery time is average. Pumping artifacts are not likely on this setting. My favorite setting for vocals (~in/out both at 5-6)3. The Output Gain control allows for adjustment of the final signal level (makeup gain) after limiting. Higher settings on this control will provide a stronger signal (indicated by the Gain Reduction meter).
(2) Normal - transients enhanced. Punchy attack with a fast recovery. My favorite setting for drums (~in/out both at 4-5).
(3) Fast - serious color (noticeable harmonic overtones), especially to mids, mid-lows, and lows, but nothing harsh. Very fast recovery. Need to be mindful of potential pumping artifacts.
TUBE PRE-AMP EMULATION
This plugin emulation is designed to deliver all the responsiveness and sound of its hardware counterpart. It could be argued that a software will never completely capture all the nuances of tubes and circuitry, but if the difference is nominal and so is the cost — what’s not to love? Not to mention, all the conveniences that plugins offer over hardware, e.g., physical space, hum, warm-up time, tube replacement, etc. In addition, this software version includes a few improvements, like a Output Trim, Dry/Wet mix knob, and the ability to adjust the noise floor down to -120dB (completely off). Additionally, the noise floor level trim knob is an excellent new feature for users who either want a touch of masking for high-end harmonic distortion or a completely clean output.*The algorithms accurately models the behavior of the ‘Light History' effect in optoelectric circuitry.*The developers have created an audio plugin that simulates and detection and manipulation of light. I’m far from being an expert on the interactions between light and electrical fields, but I know one thing for certain — whatever the mad scientists at Brainworx brewed in the lab has led to a very impressive audio effects plugin! All-in-all, the algorithms do an amazing job of reproducing some of the primary benefits of tube pre-amps:
• Increased headroom to compensate for any unpredictable signal levels and/or unexpected transients.
• Sonic elasticity.
• Protection from slew-rate limits that tend to produce harsh-sounding high-frequency transients (cymbals).
• Better transparency.
Can a limiter that adds color be transparent? If we think of transparency and color as being two opposing points on a line, then I believe this plugin can flow back and forth between slight transparency to moderate colorization, depending on the settings used. I’m no technical expert by any means, but this is what my ears are telling me to type. This plugin goes beyond the limits of single compression speed, featuring virtual algorithms of a triple optoelectronic circuit, which combine three fantastic compression curves into a single plugin. As a result, the overall breadth of tonal character ranges from precise and silky smooth to “harmonically rich” and full of warmth.
Everything I ran through this plugin sounded bigger, fatter, and richer. It seems to add warmth while enhancing the low-mids and bass. More specifically, drums squish into a lovely punch, basses compress into a nice thump, guitars and synths thicken, and vocals seem to have a lovely dark. mud-free presence. All in all, tracks benefit from the added color and compression, and with a little care the dynamics are well preserved and no noticeable noise is introduced. The Opticom plugin especially shines on vocals, in a lovely mysterious way. The tone, in general, is said to be more colorful than the LA-2A, which was the original source of inspiration — the. Is this a compressor or tone box? Well, it’s marketed as an opto-electric leveling amplifier, but based on my hours of madness, it can be used for both — coloration and compression! It depends on which of the three Response selector positions you choose and how far you twist the gain knob. Users can purely use this plugin as a tone box for coloration via the Amp mode.This is a very powerful feature that takes Opticom into territory well beyond that of other leveling amplifiers.
LESS IS MORE
With great power comes at least a little responsibility. This fantastic leveling amplifier is capable of so much compression and tone by a couple simple dial twists and switch flips. But too much can be too much. A little care needs to be taken, especially when gain staging; yet, this plugin is far from delicate. It takes reckless tweaking to destroy the lovely sonic details and edge. Most conservative adjustments produce amazing results. One thing is for certain — users won’t have to worry about sizzling tubes or frying circuitry!
• Easy purchase, download, install, and authorization process
• Sleek, elegant interface
• Easy to navigate; Simple to operate; Utilitarian
• Expansive compression character range
• Remarkable results can be achieved quickly
• Noise floor is adjustable from –60dB to –120 (off).
• CPU efficient
• Good $ value when considering the price of its hardware counterpart
• Part of Plugin Alliance — a responsive, professional team
• The position of the in/out meter switch could be clearer. I realize the interface is true to the hardware model; however, it’s difficult to see the position of the switch.
• According to the Acme Audio Manufacturing Company, the Opticom XLA-3 hardware unit by is “an optical audio limiter built to exacting military-style specifications.” Are they referring to the look? The durability? I’m really not sure what they mean by that sentence, but it sounds really cool.
Opticom XLA-3 is a three-control, two meter wonder! This virtual gem delivers all the character and charm that made the Acme Audio rack mount unit a winner. In addition to being an amazing leveler, users may also discover that it’s a magical tone box that adds pleasing colorful transients without destroying dynamics. Everything I ran through Opticom simply sounded better, especially vocals. Some words I would use to describe this beast: Luscious! Rich! Dreamy! I downloaded the fully functional, 14-day demo, and it took me less than a day to admit I needed to have this longterm! I plan to use this in any and every way possible. I highly recommend this plugin to anyone working with digital audio. Without reservation, I give the Acme Opticom XLA-3 an unlimited, colorful thumbs up. Congratulations to Plugin Alliance for adding this stunning leveling amplifier to your exquisite collection of audio plugins.
• Sound Quality: 5/5 - It sound amazing.
• Ease of Use: 5/5 - It has three controls and two meters. The only plugin I can think of that’s easier to use is Sausage Fattener.
• Features: 4/5 - It has what’s needed, nothing more and nothing less.
• Bang for the buck: 4/5 - This is a tough one. It cost almost $300, which some might consider a lot for an effects plugin, but I’m giving it 80% because the price tag is only 10% of its hardware counterpart.