 Then, in an attempt to satisfy fans of stereo, a number of "reprocessed" or "electronic" stereo versions were issued; generally, these were less than satisfactory because the tapes seldom had high enough fidelity to justify the separation of highs and lows, changes in equalization for each channel, or use of out-of-phase effects; however, there were a few exceptions where the process enhanced or actually improved the original mono recordings.Some of the album liner notes in the Toscanini series included the dates and locations where many of the recordings were made, which was rather unusual for the time.Victrola also went well back into the RCA Victor archives to issue collections of various operatic singers, as well as groups of singers.