SPL BiG is a stereo image Bigger Maker with a few extra tricks to it, as well as enhancing the overall stereo image, it can pull the low end into focus and add what they call Bass Air - which seems to add some space and definition to the low end around the kick drum and bass.
SPL have been adding special sauce to audio signals for many years, and is often found in the mastering chain.
The BiG is now available (or will be later in the Summer) as a 500 Series rack module with a price of $649
More info: https://spl.audio/en/spl-produkt/big/
Music store tour
And you can buy it now
It truly is a bass synthesizer
Gets an update