The audio industry has created in the past two very different types of devices for visual indication of audio program levels, i.e. the Volume Unit meter and the Peak Program Meter. Their existence has always been characterized by many controversies, misunderstandings, discussions, pro's and con's. With the newly available electronic display methods (LED's, et al) much will change in the established situation in the near future. Every audio engineer should clearly understand what VU's and PPM's really indicate. In a step by step educational method, the basic differences between both instruments are explained for continuous signals, and are also related to the RMS-value. Next, easy lining up methods of normal operation level on tape are given, using a VU or PPM meter only. A completely new proposal for a calibration test tape will be made during the panel discussion of the 56th convention (not included in this preprint) which shall be compatible for lining up with VU or PPM measurement.
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