[JohnM]

Sorry for the delay in chipping in here, I'm once again away on business and not home until middle of next week.

The frequency response average can be used as an overall target (not the impulse reponse average, which as Bruce noted is not suitable for different positions). However, it is typically better to view the various responses and make a judgement about what to correct depending on whether a particular peak is common to all or many locations (so definitely want to correct it) or only appears in one of a small number of locations (so may go for a smaller correction to balance out the positive effect where there is a peak versus the negative where there isn't). In general peaks are more objectionable than dips, so even corrections that are not needed in all positions are often worth applying. What you should never do is try to apply a boost unless it is to counter a shallow dip in all locations (and hence is countered by a fairly broad filter). Any narrow boost filter will make the response worse in most if not all locations.