According to an article in Digital Music News, some mastering engineers are beginning to tailor their masters depending on the final playback format.
In Digital Music's interview with mastering engineer Vlado Meller, he said, "We believe that this (multiple masters) will become more of a standard practice in the music industry." I checked in with my friend and Grammy-winning mastering engineer, David Glasser at Airshow Mastering and asked him about multiple mastering for different final formats. He told me, "We use the same mastering set-up but for CDs and LPs. But the LPs don't get the final peak limiting stage. I usually put a final peak limiting process because the CD is typically mastered at a slightly higher level." When I asked David about mastering specially for AAC or other lossy formats he told me, " I haven't had any clients request this yet, but I would probably master at a slightly lower peak level for lossy formats because they do not handle higher peak levels well."
In the Digital Music News article Meller also mentions, "To get the vinyl to sound its best...adjustments in tone and level are made so that the vinyl plays back without distortion and without skipping." This is as specific as the article gets as to what are the EQ differences between the LP and CD masters. Obviously this strongly implies that some equalization and tone adjustments are being made which are subjective in nature.
Any Red Hot Chili Peppers fans want to weigh in on whether they hear differences between the LP and CD?