When a composer organizes elements on staff paper (notes, timbres, rhythms, etc), one can say that these elements have only a virtual existence in the composer's mind, and that they await something that will give them a graspable presence, a “concretization” represented in this case by the performance of the work in question. Musique concrète, on the other hand, works from materials whose sonorous existence is present immediately. These sound objects are the natural or artificial results of recordings—natural if the recorded sound is used in its raw state, artificial if it is subjected to some transforming operation: sounds lacking the attack, reversed, filtered (suppressing the lower or higher harmonics), reverberated, etc. Thus the sound objects become, in the manipulator's hand, like the different degrees of a scale, except that the concrete musician builds his score with the help of turntables and tape machines, so creating at once the work and its performance.