Summary of Results

A graph of the frequency response data before any optimization is repeated below, showing large deviations from flat response and large seat-to-seat variation.

Figure 43. Combined responses before optimization

The results after the first optimization as performed in the tutorial_4_prefab.msop in the Sample Projects sub-folder of the tutorial are shown below.

Figure 44. Combined responses after first optimization

You can see clear improvements in both overall flatness and response variation from seat to seat.

The final filter responses are shown below.

Figure 45. Filter responses after optimization

No boosting is done in any of the PEQ filters.

Next, the MLP response was made as flat as possible using the following steps.

Clone the Optimized configuration, renaming it MLP Cleanup.
Lock all the filter parameters of the MLP Cleanup configuration.
Use Rearrange Gains and Rearrange Delays to make a shared delay block and gain block available in the MLP Cleanup configuration.
Unlock the parameters of just the shared gain and delay blocks.
Add six PEQ filters to the Shared Filters of the Subwoofer Channels of MLP Cleanup.
Make all measurement groups except the MLP plot-only in MLP Cleanup.
Re-run the optimization.

This gives the results shown below.

Figure 46. Optimization results of MLP cleanup

It is interesting to compare the final gain and delay settings of the first optimization and the final one. After the first optimization, the following results were obtained.

Final gain and delay/distance settings:
Increase AVR sub out trim gain by 1.5 dB
Sub Channel 1 gain: -5.63 dB
Sub Channel 2 gain: -0.07 dB
Sub Channel 3 gain: -14.09 dB
Sub Channel 4 gain: -4.23 dB
Decrease AVR sub out distance by 3 feet
Delay settings:
Sub Channel 1 delay: 12.35 msec
Sub Channel 2 delay: 4.54 msec
Sub Channel 3 delay: 4.46 msec
Sub Channel 4 delay: 0.05 msec

Here are the results after the final optimization.

Final gain and delay/distance settings:
Increase AVR sub out trim gain by 9.5 dB
Sub Channel 1 gain: -5.90 dB
Sub Channel 2 gain: -0.33 dB
Sub Channel 3 gain: -14.36 dB
Sub Channel 4 gain: -4.50 dB
Increase AVR sub out distance by 12.4 feet
Delay settings:
Sub Channel 1 delay: 12.35 msec
Sub Channel 2 delay: 4.54 msec
Sub Channel 3 delay: 4.47 msec
Sub Channel 4 delay: 0.05 msec

The AVR sub out gain of the final optimization is 8 dB higher than the first one. The AVR sub distance of the final optimization is a surprising 15.4 feet greater than the first optimization. This is probably due to the added phase shift of the shared PEQ filters used in the final optimization.

It's not completely clear whether the final effort to flatten the MLP was worth the side effects. Though the final MLP response is much flatter than in the first optimization, the listening positions other than the MLP have been made slightly worse.