New Software Review: Gullfoss by Soundtheory

Not quite a compressor, de-esser, EQ—or any other common tool—Soundtheory’s Gullfoss offers a unique approach to mix refinement.

It’s rare audio professionals are presented with entirely new technology in today’s age of digital audio processing. Soundtheory, the brainchild of co-founders Andreas Tell and David Pringle, however, is doing just that with the release of Gullfoss.

Gullfoss is the first in Soundtheory’s line of products to employ their highly advanced model of computational auditory perception to open up new possibilities of analyzing sound as it is perceived by human ears, and processing it in novel ways, without degradation.

While Gullfoss can be used to serve as a more elegant solution to problems we address with traditional tools like de-essers, active equalizers, multi-band compressors, and the like, it doesn’t quite fit any of these classifications. Let’s take a closer look and see what Gullfoss is all about.

Features

Available for macOS and Windows in AU, VST, VST3, and AAX Native formats, Gullfoss uses Tell’s computational auditory perception model to distribute the brain’s attention amongst the audible elements of a signal. It does so by altering the level of these individual elements while simultaneously keeping the overall perceived volume the same. Even without access to individual tracks, you can correct balance issues in a mix with unprecedented ease and precision using Gullfoss.

Employing only a handful of controls, this easy-to-use tool is capable of changing its optimum frequency response over 300 times per second while preserving the integrity of the original signal. There are truly no audible artifacts or issues of sound degradation, despite these highly dynamic equalization changes.

Gullfoss’ GUI is essentially a large frequency graph with 5 parameters across the top for Recover, Tame, Bias, Brighten, and Boost. Increasing the Recover percentage will make Gullfoss work harder to treat the elements that are being dominated. Increasing the Tame percentage will make Gullfoss work harder to treat the elements that are dominating. The Bias control then sets a value for Gullfoss’ preference to Recover or Tame in the marginal cases where both could have benefit.

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Positive numbers increase the preference to Recover, and negative numbers increase the preference to Tame. The Brighten parameter only is in effect if Tame or Recover are set to a non-zero value. It then helps dictate the Tame and Recover decisions needed to achieve the desired brightness. It can help to compensate for any perceived loss of high end in the process, or it can help to adjust for the high end expectations of different genres. A negative percentage will sound darker and a positive percentage will sound brighter.

The Boost parameter simulates a change in frequency balance as the listening volume changes, emphasizing bass and reducing midrange frequencies when increased. This produces a similar effect to that of the Fletcher-Munson curve, however Soundtheory describes their model as more advanced and not actually based on Fletcher-Munson. This is a particularly unique control for manipulating perceived loudness.

In addition to these 5 primary parameters, an output gain adjustment is provided at the bottom of the right-side output section. Impressive metering will help you better understand what Gullfoss is doing by providing valuable visual feedback. On the left is a +/-24dB scale that displays if Tame or Recover is in effect, and the amount that it is working. Positive values display the amount of Recover, and negative values display the amount of Tame. At the bottom (just above the amplitude meters) is a horizontal meter that displays how the current processing is affecting the brightness of a signal. The primary graph display shows how Tame and Recover are working across the frequency spectrum.

An interesting additional feature of this display is the frequency limit markers. While many will use Gullfoss for mastering and its full spectrum benefits, you can restrict what frequencies will be affected with these two limit markers. This is perfect for implementation in a mix to address specific issues and still retain elements you like.

If the bottom end frequencies of a vocal stem sound right to you but the top end frequencies are harsh on certain layers, you could define the area for Gullfoss to address with the limit markers and still keep the rest of the spectrum unaffected. This example highlights that Gullfoss is much more than a plugin for your master chain. With its unique set of parameters and technology under the hood, this plugin has limitless potential for powerful unadvertised use.

In Use

I found use for Gullfoss in a wide variety of mix scenarios. I used the Boost to my advantage in a mix recently which had a thin and harsh sounding drum loop. I pushed this parameter until the bottom filled out and the mids were put in check, and my problem was solved.

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The same mix had an acoustic guitar with some harsh fret noise. I used the frequency limit markers to define the harsh region, pushed Tame until it felt smooth, and then compensated with a little bit of the Brighten parameter. I employed a similar technique in a different mix working with live cymbals that needed to be controlled but still present.

This plugin really has enabled me to solve the same old problems by coming at them from a new angle. There is no tool on the market that can manipulate elements the way Gullfoss can. I was even able to bring out a harmony in a background vocal stem simply using Recover and Bias, even though I didn’t have the individual tracks.

Additionally, in its advertised use as a mastering plugin I was blown away. Gullfoss gives a final polish that when stripped leaves you wanting more. Once you hear the effect, you feel like something is missing if you bypass it; the sound is suddenly less firm and generally less “finished.” Gullfoss can both expose problems you may have not even noticed, as well as address them in a musical and non-invasive manner. This makes it even a powerful mix diagnostic tool, letting you know what areas need to be addressed.

To Be Critical

It’s not often you encounter a tool that you feel can’t benefit from some type of refinement, whether it’s rooted in user experience or actual functionality. While I’m hesitant to use a word like “flawless,” I genuinely have no criticism of Gullfoss.

With its advanced audio analysis capabilities and total ease-of-use with its limited yet highly effective parameters, Gullfoss is essentially the first tool of its kind. I’m excited to see what other applications Andreas Tell and the rest of Soundtheory have in mind with this technology.

Summing it Up

Overall in my time researching and experimenting with Gullfoss, it has become clear to me that this is a tool with massive benefits for audio professionals across many different fields. In the music space alone, producers, mixers, and mastering engineers all stand to benefit.

Priced at $199, Gullfoss may not be suitable for the hobbyist on a budget who may have less of a concern for high-quality sound. However, the price is certainly justifiable to someone making a living in audio who needs to turn out pro results quickly.

I am certain Gullfoss will help a professional reach the finish line faster, whether editing podcasts, audio for video, producing/mixing/mastering music, or doing any other job that is defined by quality sound. I highly recommend you try Gullfoss and see if it has a place in your workflow… it just might be the thing that takes your sound to the next level!

Jake Goodman is a freelance audio engineer and Studio Manager/Engineer for Pulse Recordings in Los Angeles, CA.

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