Frequency Response versus Time-of-Arrival for Typical Cinemas

Cinema equalization is typically based on the use of 1/3-octave, minimum-phase filtering to adjust the spatial average of the steady-state magnitude response from multiple microphones to the X-curve. This paper explores one aspect of this process, namely whether the use of steady-state response is appropriate. The relationship between early-arrival and steady-state spectral characteristics for typical cinemas was examined. — The comparison between early-arrival and steady-state sounds was done via spectral analyses of impulse responses measured at multiple microphone locations within the audience seating area. The cinemas surveyed varied in size between 30–500 seats and the time-gating intervals varied from 4 ms to that equivalent to steady state. When the survey was done, front loudspeaker measurements above 500 Hz showed little spectral tilt upward toward “brightness” for early-arrival, compared to steady-state sounds, and a modest upward tilt for surround loudspeaker arrays in the largest cinemas. Larger response differences occurred below 500 Hz.

Published

2012-10

Content type

Original Research

Keywords

Cinema Measurement, Cinema Equalization, Cinema Acoustics, Cinema Standards, Time Frequency Analysis, B-chain

DOI

10.5594/M001481

ISBN

978-1-61482-952-2