Clarion’s ADF, or Anti-Distortion Filter, was created specifically for the purpose of enhancing the listening experience of your MP3 and WMA music collections. During compression, the fidelity of your music is drastically reduced so you can fit more files onto one recordable CD. That’s where ADF comes in. Smoothing out the audio signals so that high and low frequencies remain audible, ADF restores your MP3 and WMA music files so they sound like the original recording. Best of all, there’s no added frequency boost, which can result in dull, muffled sound. So, if you want your MP3 and WMA music files to sound cleaner and crisper, engage the ADF feature ... becaue at Clarion, we believe your compressed music collection shouldn’t have to sound compressed.