How to Interpret the Graphs (Continued)
Deciding the time period for Advanced EQ Setup calibration
With conventional MCACC EQ calibration, the microphone input’s data acquisition time was fixed at between 80 and 160 [ms] (red part of Figure 1). By contrast, with the receiver’s Advanced EQ Setup function allowing more professional equalization, the customer can select individual points between 0 and 80 [ms] (with a 20 ms width) (blue part of Figure 1).
Note
You can specify the time period setting using the “Advanced EQ Setup” in the “EQ Professional”
Figure 1 Comparison of microphone data acquisition time periods
Level (dB)
EQ calibration time range | Conventional MCACC EQ | |
selectable for Advanced | calibration time range | |
EQ Setup function | (fixed) | |
(selected automatically for | ||
Full Auto MCACC) |
| Time (in ms) |
|
| |
To decide the time period for Advanced EQ Setup calibration, view the graphs of the measured reverb characteristics, and refer to the following three patterns.
Pattern 1: Different reverb characteristics for high and low frequencies
In rooms with reverb characteristics like those shown in Figure 2, lower frequencies often seem overly reverberant compared to higher frequencies (i.e. the room sounds ‘boomy’). With conventional MCACC EQ calibration, data between 80 and 160 [ms] (red part of Figure 2) was acquired, so the low frequency volume was deemed high and the high frequency volume deemed low, and the equalization curve was calibrated with the high frequencies somewhat boosted. However, for the characteristics of the sound reaching the ear directly within about 40 ms, there is enough volume that there is no real need to boost the high frequencies, so with equalization using the conventional MCACC EQ calibration the high frequencies sometimes sounded too strong. Therefore, the Acoustic Cal EQ may result in a room where high frequencies sound shrill. In cases like this, setting the time period for Advanced EQ Setup to 30 to 50 msec (the blue area
in Figure 2) to adjust for sounds coming directly from the speakers can flatten the frequency response for direct sounds (including initial reflections) and give a
Figure 2
Level (dB)
Low frequencies
High frequencies
Time period 
point to be
selected
Time (in ms)
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