The Aphex Exciter and Optical Big Bottom delivers increased presence, depth, and clarity to your recording, mixing, and mastering projects and does it all with little or no increase in peak output. The Exciter's patented processes restore natural brightness to your music through dynamic harmonic enhancement. In a mix, this creates more space and dimensionality and gives individual tracks room to breathe. The Optical Big Bottom adds density to the low end that increases presence and punch and dramatically enhances bass frequencies without overloading speakers or recorders. Single rackspace.