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Slate Digital's Custom Opto gives you precision control over the classic LA-2A sound

slate custom opto
(Image credit: Slate Digital)

Compression is one of the most essential tools in any producer’s arsenal, whether you’re adding weight to your kick drum, bringing character to a vocal take or mastering your entire mix - and though the number one job of your compressor is to control and shape dynamics, there’s plenty more that it can do.

Many people use compression to bring fullness, tone, and warmth to their productions, and there’s no type of compressor that does this better than the opto. 

Opto, or optical, compressors are named after the optical photocell arrangement in their gain reduction circuit. In other words, they use a light source and a light detector to control audio signal levels. Opto compressors convert an incoming audio signal into light, which is emitted by an LED and then detected by a light-sensitive resistor.

As the audio signal’s amplitude increases, the light source increases in brightness. The amount of light that hits the resistor then determines the amount of gain reduction that’s applied to the audio signal, and the amount of compression that takes place. 

The way an opto compressor works is unique, and that’s what gives it such a unique sound. Opto compressors are known for injecting character into mixes, making them sound larger than life: they produce a rich and buttery analogue warmth that you’ve probably heard before, perhaps without knowing it came from an opto.

More than just a gain-control device, these kinds of compressors are an effect in themselves, and are perfect for adding punch and fatness to vocals, guitars and bass. 

When it comes to opto compressors, there’s one that set the bar high for all others to follow. The Universal Audio Teletronix LA-2A is a legendary optical tube compressor that was first manufactured in the early ‘60s, and is still in high demand today. It provides everything that we want from an opto: vintage character, analog warmth and a smooth, balanced tone. 

However, it also suffers from one drawback that is also commonly associated with opto compressors, offering producers less control over how they shape their sound than other types of compressor. Vintage-style optos often have limited control panels, and the LA-2A is no exception, with just two control knobs, one for gain and one for peak reduction.

So what if you could build a compressor that offers the tone, warmth and fullness of the LA-2A, with the level of control producers need to nail down perfect mixes? Slate Digital have answered that question with the Custom Opto.

While creating their phenomenal software emulation of the LA-2A, the FG-2A, the experts at Slate obsessively studied classic optos, until they realized that they were able to enhance the classics by adding sound-shaping controls to give producers a level of precision never seen before in this type of compressor. 

The Custom Opto’s Speed control determines exactly how fast the compressor reacts, giving you full control over attack and release and allowing you to dial in the action of the compressor easily and accurately.

In addition, the Custom Opto lets you tune up the perfect level of compression using a control knob that’s common in most compressors but notably lacking from the original LA-2A: ratio. 

The Tone knob offers four custom sonic vibes, each with a unique character, that can be modified in their intensity using a separate control. Warm injects some vintage mojo, and Aggro pumps up the mix with some weight and punch. Smooth dials down harsh frequencies, while Airy breathes new life into your top end.

Finally, the Mix knob enables producers to fine-tune the overall intensity of the plugin, allowing for quick and easy parallel processing. Together, these controls allow producers to apply detailed, powerful compression to their mixes and hot rod their sound.

The FG-2A brings a warmth, smoothness and analogue vibe that’ll make your tracks sound like a record straight off the shelf. Combined with the precision of the Custom Opto, these two plugins give you total control of your mix.

Slate Digital’s subscription service, the All Access Pass, gives producers access to both of these powerful compressors, as well as over 60 other pro plugins, royalty-free sample packs, and new monthly synth preset packs.

Visit Slate Digital’s website to hear how the Custom Opto sounds and find out more about the All Access Pass.