Audio metering : measurements standards and practice Acoustic sound From acoustic sound to electrical signals Digital representation Signal types How large is an audio signal The dB concept The ear hearing and level perception Time weighting Frequency weighting and filters Determination of loudness Characteristics of level meters The standard volume indicator (VU meter) Peak program meter PPM Loudness metering Calibration of level meters Relationships between scales Dynamic scales polarity and phase reading Display of level distribution Multi channel and surround sound Standards and practices Summation of audio signals Digital interface Where to connect a meter Fast fourier transformation Spectrum analyzer Other measurement systems Measurement signals Sound level meters NR and NC curves Room acoustics measures.