This Seems to Go Too Far. The AP reports in "Court: Sampling May Violate Copyright Law." From the article: "A federal appeals court ruled Tuesday that rap artists should pay for every musical sample included in their work — even minor, unrecognizable snippets of music." Copyright liability for sampling three notes seems to run afowl of the de minimis limitiation on copyright protection. You can access the Sixth Circuit's opinion here, where you will find the following response to my de minimis argument:

This analysis admittedly raises the question of why one should, without infringing, be able to take three notes from a musical composition, for example, but not three notes by way of sampling from a sound recording. Why is there no de minimis taking or why should substantial similarity not enter the equation.(10) Our first answer to this question is what we have earlier indicated. We think this result is dictated by the applicable statute. Second, even when a small part of a sound recording is sampled, the part taken is something of value.(11) No further proof of that is necessary than the fact that the producer of the record or the artist on the record intentionally sampled because it would (1) save costs, or (2) add something to the new recording, or (3) both. For the sound recording copyright holder, it is not the “song” but the sounds that are fixed in the medium of his choice. When those sounds are sampled they are taken directly from that fixed medium. It is a physical taking rather than an intellectual one.