Tips to improve encoded sound quality¶Master at -2 dBFS instead of -.1 dB. - Audio encoders tend to output hotter than the source.Don't overcompress. Keep some dynamics in your master, it will encode better.Roll off a little of the top end (16K+)Keep the master at or below -15 dB RMS/-16 LUFS to avoid iTunes "Sound Check" from lowering the level on playback. Master at -2 dBFS¶Mastering lower than -.1 dB provides some headroom for the codec to do it's work. Audio encoders tend to output hotter than the source, leaving a little bit of headroom can prevent clipping when the audio is encoded. Søren H. Nielsen and Thomas Lund wrote a great paper detailing the Overload in Signal Conversion problem.Roll off a little of the top end (16K+)¶Rolling off the top end serves two purposes: These frequencies take up a lot a bandwidth and cause your encoded audio to need more storage space, which leads to:Audio encoders roll off and cut higher frequencies to reduce the resulting file size. See also¶Apple's Official Mastered for iTunes InfoArsTechnica: how audio engineers tweak music for the iPod ageBobby Owsinski: Latest on Mastered for iTunesCreateDigitalMusic: Op Ed: What Do "Mastered for iTunes" and "Sound Check" Do To Music Listening?definition of decibelMixing - Target Systemstc electronic - techlibrary - Papers and Articles about Audio Fidelity and Processing published by TC Developers and other Industry Professionals.