The Aphex EQF 500 500-Series 3-Band Semi-Parametric EQ is a single-slot 500-Series 3-band semi-parametric EQ based on the Aphex EQF-2. Its low band ranges from 25 to 500Hz, its mid band from 250Hz to 5kHz, and its high band from 1 to 20kHz. Each band can be boosted or cut by up to 12dB, and the high and low bands can be switched between shelving and peak EQ curves. It also features a variable high-pass filter at 20 to 500Hz and a variable low-pass filter at 1 to 20kHz. The EQF 500 requires a 500-Series power supply for operation.