Gullfoss is an intelligent EQ plugin that dynamically changes the EQ up to 100 times a second to “increase the perception of clarity, space and dimension” in recorded content (Tavaglione, 2018). It does not do this with AI, neural networks, machine learning, psychoacoustics, or DSP techniques. It does it using a proprietary “computational auditory perception technology” (Soundtheory, 2018).
It is different to the AI assisted mixing used by companies like iZotope in that it does not use neural networks or machine learning to produce the output (Tavaglione, 2018). This helps Gullfoss with its ability to do the processing in real-time. Machine learning on the other hand needs to process the data and then act accordingly. This takes time to go through the dataset and the model for it to work (ibid.).
So, what does that mean in practice? It allows producers the ability to enhance recordings in real-time to sound better. And it works. You can apply Gullfoss to individual tracks, the whole mix, or anything in-between. With five simple controls, even when applied to the mix bus, the plugin can create separation between instruments and create a clarity that was not there before. The controls are: Recover, Tame, Bias, Brighten, and Boost.
Recover and Tame are used to reveal masked signals to improve clarity, detail, and space in the mix. Recover brings up elements that have been masked by more dominant elements, while Tame brings down elements that are masking less dominant elements. Both Recover and Tame utilise both boosts and cuts in frequency but in different ways to preserve dynamics and loudness.
Bias and Brightness allows producers to control how Recover and Tame are applied to the signal. A positive Bias value allows Recover to affect a wider range of frequencies, while a negative Bias value allows Tame to control a wider range of frequencies. Brightness is the parameter that lets Gullfoss know if it should prefer unmasking higher or lower frequencies.
The final control is Boost. It simulates the change in frequency balance based on human perception of volume. This is different to just turning up the volume of a track. As human hearing and perception of volume is not linear across frequency – I’m looking at you Fletcher Munson Curve – (Stewart, 2022) turning this up with turn up bass frequencies while turning down mid frequencies.
References
Soundtheory (2018) Reveal your sound, Soundtheory. Available at: https://www.soundtheory.com/about (Accessed: March 22, 2023).
Stewart, I. (2022) What is the fletcher munson curve? using equal loudness curves in mixing and mastering, iZotope. iZotope, Inc. Available at: https://www.izotope.com/en/learn/what-is-fletcher-munson-curve-equal-loudness-curves.html (Accessed: March 22, 2023).
Tavaglione, R. (2018) Gullfoss inventor andreas tell tells all!, Mixonline. Available at: https://www.mixonline.com/blog/gullfoss-inventor-andreas-tell-tells-all (Accessed: March 22, 2023).
White, P. (2023) Soundtheory Gullfoss. Available at: https://www.soundonsound.com/reviews/soundtheory-gullfoss (Accessed: March 22, 2023).