The Sonarworks Reference 4 Headphone is a headphone calibration plug-in to correct uneven frequency response occurring due to physical constraints. Sonarworks Reference 4 for headphones works by using a calibration profile accessible in your DAW via the dedicated plug-in to make your headphone sound as neutral as possible. The frequency correction is visible in the frequency graph of the plug-in with left and right drivers visible individually. Sonarworks Reference 4 Headphones Main Features: Headphone calibration plug-in VST, AU, AAX, RTAS formats Average calibration curves for 32 headphone models Output clipping protection, Simulation section Transparent minimum, mixed or linear phase filters The Sonarworks Reference 4 for headphones works natively with the following headphones: AKG: K141 mkII, K240 Studio, K271 MkII, K701, K702, K712 Pro, K812, K44, K77, Q701 AIAIA: TMA 1PU foam pads Audeze: LCD-X, LCD-2 Audio-Technica: ATH-M20x, ATH-M40x, ATH-M50x, ATH-M70x, ATH-R70x, ATH-M30x Beats: Mixr, Pro, Solo 2, Solo 3, Studio 2 (2nd generation), EP Beyerdynamic: DT770, DT880 Pro, DT990 Pro, DT1770 Pro, DT1990, T1 Blue: Lola, Mo-Fi Bose: QuietComfort 25, QuietComfort 35 Direct Sound: Extreme Isolation EX-25, Extreme Isolation EX-29 Focal: Spirit Pro Fostex: T50RP Grado: SR60e Koss: Porta Pro Classic KRK: KNS8400 Marhall: Major II, Monitor Oppo: PM-3 Philipps: SPH9500 Pioneer: HDJ-500 Sennheiser: HD25 (70 Ohm), HD25 II, HD25 Light, HD201, HD202, HD280 Pro, HD380, HD598, HD600, HD650, HD700, HD800 Shure: SRH840, SRH1840, SRH440 Skullcandy: Hesh 2.0 Sony: MDR-7506, MDR-7520, MDR-CD900ST, MDR-V150, MDR-XB650BT, MDR-XB950AP, MDR-XB950BT, MDR-ZX110, MDR-ZX310, MDR-ZX770BN Superlux: HD681 Yamaha: HPH-MT220