A mixed domain approach

It is possible to have the best features of both domains by using a mixed domain approach. Figure 5 shows the results after bandwidth equalization in the frequency domain and phase-matching with a 12 point time filter.

 

mixed
Figure 5 Results of mixed domain match-filtering. Left is filtered base survey, center is filtered monitor survey and right is the difference. S/N = 9.50

Tackling the problem in this way, you have control over the spectra, and do not need to worry about constraining the wildly oscillatory phase of an all-pass filter.