Soundtheory Gullfoss Intelligent EQ

There are zillions of audio plug-ins on the market to enhance your DAW or NLE. In most cases, the operation and user interface design is based on familiar physical processing hardware. Often the user interface design is intentionally skeuomorphic as either a direct analog to the physical version or as a prompt to give you a clue about its processed sound and control functions.

When you first open the Gullfoss equalizer plug-in, you might think it works like many other EQ plug-ins. Grab a frequency point on the graph line, pull it up or down, and spread out or tighten the Q value. But you would be totally wrong. In fact, this is a plug-in that absolutely requires you to read the manual. Check out the tutorial videos on the Soundtheory site and its operation will make sense to you.

Soundtheory launched Gullfoss (which gets its name from the Gullfoss waterfall in Iceland) as its first commercial product after years of research into perceived loudness. According to Soundtheory, Gullfoss is not using artificial intelligence or other machine learning algorithms. Instead, it employs their computational auditory perception technology. More on that in a moment.

Gullfoss installs as an AU, VST, and AAX plug-in, so it’s compatible with a wide range of DAWs and NLEs. License management is handled via iLok – something most Pro Tools users are very familiar with. If you don’t own a physical iLok USB key (dongle), then license management is handled through the iLok License Manager application. You would install this with a free iLok account onto your computer. iLok management allows you to move the plug-in authorization between computers.

The Gullfoss equalization technology is based on balancing dominant and dominated frequencies. The plug-in automatically determines what it considers dominant and dominated frequencies and dynamically updates its processing 300 times per second. User control is via the Recover and Tame controls.

Increasing the Recover value accentuates dominated frequencies while Tame adjusts the emphasis of dominant frequencies in the mix. Bias controls the balance between Recover and Tame. A positive value shifts more of the processing based on the Recover frequencies, whereas a negative value shifts the emphasis towards Tame. Brighten tells the Recover/Tame mechanism to prefer lower or higher frequencies. Boost balances low versus mid frequencies. Positive values favor bass and negative Boost values decrease bass and increase mids. Finally, there’s an overall gain control and, of course, Bypass.

By default, you are applying Gullfoss processing to the complete sound spectrum of a track. There are left and right range boundaries that you can slide inwards. This restricts the frequencies being analyzed and processed to the area between the two boundary lines. For instance, you can use this with a tight range to make Gullfoss function like a de-esser. If you invert the range by sliding the left or right lines past each other, then the processing occurs outside of that range.

One tip Soundtheory offers as a beginning point is to set the Recover and Tame controls each to 50. Then adjust Bias and Brightness so that the small meters to the left and bottom of the graph hover around their zero mark. This provides a good starting point and then adjust more as needed. Quite frankly it requires a bit of experimentation as to how best to use it. Naturally, whether or not you like the result depends on your own taste. In general, this EQ probably appeals more to music mixers and less to video editors or audio post engineers. I found that it worked nicely as a mastering EQ at the end of a mix chain or applied to a completed, mixed track.

I’m a video editor and not a music mixer, so I also tested files from a corporate production, consisting of a dialogue and a music stem. I ran two tests – once to the fully mixed and exported track and then also at the mix with the two stems isolated. I found that the processing sounded best when I kept the stems separate and applied Gullfoss to the master bus. Of course, this isn’t the best scenario, because the voices and music cues would change within each stem. However, with a bit of experimentation I found a setting that worked overall. It did result in a mix that sounded clearer and more open. Under a proper mix scenario, each voice and each music cue would be on separate tracks for individual adjustments prior to hitting the Gullfoss processing.

In regards to music mixes, it sounded best to me with tracks that weren’t extremely dense. For example, acoustic-style songs with vocals, acoustic guitars, or woodwind-based tracks seemed to benefit the most from Gullfoss. When it works well, the processing really opens up the track – almost like removing a layer of mushiness from the sound. When it was less effective, the results weren’t bad – just more in the take-it-or-leave-it category. The Soundtheory home page features several before and after examples. As a video editor, I did find that it had value when applied to a music track that I might use in a mix with voice-over. However, for voice control, I would stick with a traditional EQ plug-in. If I need de-essing, then I would use a traditional, dedicated de-esser.

Gullfoss is a nice tool to have in the toolkit for music and mastering mixers, even though it wouldn’t be the only EQ you’d ever use. However, it can be that sparkle that brings a song up a notch. Some mixers have commented that Gullfoss saved them a ton of time versus sculpting a sound with standard EQs. When it’s at its most effective, Gullfoss processing adds that “glue” that mixers want for a music track or song.

©2020 Oliver Peters