Effect of Microphone Number and Positioning on the Average of Frequency Responses in Cinema Calibration

Enhanced Wide-Area Low-Frequency Sound Reproduction in Cinemas: Effective and Practical Alternatives to Current Calibration Strategies

“…This results in highly position-dependent frequency responses and consequently, measurement position dependent equalization, as highlighted in detail in [7].…”

“…Recently published research [7] provides an in-depth look into the effect of a number of measurement locations and their placement on the effectiveness of spatially-averaged response equalization. The results show that only eight carefully chosen measurement locations are required to generate an average response within 4 dB to 6 dB of the system response across the audience area.…”

“…As with the single-point method, however, this calibration strategy provides no reduction in spatial variance, although it can provide greater overall response "flatness" using global B-chain equalization. Additionally, as mentioned in [7], measuring 81 points within the listening area can be a very long process in practice and is likely to be impractical for a reasonable calibration procedure.…”

“…With a more careful physical layout, the issue can be mitigated [9]. A similar issue pertaining to cinema calibration is highlighted in [7]. CSA calibration is particularly inefficient in the dubbing theater with a small, 9-point measurement grid.…”

“…Current standards and recommendations [3,4] suggest using one-third-octave band graphic or parametric equalization to smooth the low-frequency response in cinemas. These techniques are often based on spatiallyaveraged response measurements across a seating area [3], which has been proven to give minimal benefit regarding uniformity or overall "flatness" in the low-frequency band [1,2,[5][6][7]. The effect redistributes the problem rather than solves it.…”