Originally Posted by wogster
For EQ what you really need is a stepped frequency sweep, which should match your 31 bands, where say it gives you 15 seconds of each frequency then moves to the next, you monitor the sweep making notes as to where there are issues, then go to your EQ make adjustments, then go listen again to see if those issues are resolved, then go to another spot and listen.
The points about the effects of equalization potentially varying throughout the space are very good, however for type of equalization described I would much rather use a random broadband noise source or a source that represents the normal program content as those can also address more complex issues and band interaction.
I think an important factor is that how you might EQ the house and how you would typically EQ monitors may be different. Another common issue in regards to monitors is to 'ring out' the monitors on an empty stage only to have things change significantly during actual use, the closer you can come to emulating the situation during use, the more likely for any adjustments made to be relevant to the actual use. A similar issue exists for house systems where it is common to tune systems a bit 'bright' for an empty room to compensate for the effects of an audience.
Another common occurrence is to watch people try to equalize out things that can't be fixed with EQ. For example, on stage a reflection from a monitor speaker off the floor, a music stand, etc. arriving at the microphone could cause cancellation or summation at certain frequencies. Since that is a result of the relationship of the direct and reflected signals and any equalization would affect both equally, you may be able to increase or decrease the level by applying equalization but that will not alter the summation and cancellation effects. Thus the proper solution for such situations is to address the phase and level relationships of the direct and reflected audio signals, for example trying to absorb the reflection or using the microphone pattern to increase pickup of the direct sound and reduce the indirect or reflected signal level.
The stereotypical example of of these coming together is a tech ringing out the monitor system in advance only to experience feedback once the performance began that they had difficulty resolving with equalization. The problem turned out to be reflections from the monitor speaker off the broad brimmed hat the vocalist wore for the performance. As they brought the mic up to their mouth the resulting reflections would sum at certain frequencies causing feedback at those frequencies, while the summation frequencies would vary as the singer moved the microphone or their head.