Defenders of vibrato claim that the sonic limitations of 78-rpm recordings, particularly with respect to overtones and high frequency information, make an uncontroversial assessment of earlier playing techniques difficult (although, it must be said, early recordings of operatic singers manage to show clearly the extent to which a vibrato is present not in their voices). In addition, the defenders of vibrato point out a distinction needs to be made between the kind of vibrato used by a solo player, and the sectional vibrato of an entire string ensemble, which cannot be heard as a uniform quantity as such. Rather, it manifests itself in terms of the warmth and amplitude of the sound produced, as opposed to a perceptible wavering of pitch. The fact that as early as the 1880s composers such as Richard Strauss (in his tone poems "Don Juan" and "Death and Transfiguration") as well as Camille Saint-Saëns (Symphony No. 3 "Organ") asked string players to perform certain passages "without expression" or "without nuance" somewhat suggests the general use of vibrato within the orchestra as a matter of course; by the same token, indications by Mahler and Debussy that specifically demand the use of vibrato in certain passages may suggest the opposite practice.