Coherence is a common feature found on many analyzers enabling us to distinguish signal from noise. It will indicate whether you're measuring a loudspeaker or, e.g., a moving light.
Coherence is subject to change. One of the aspects involved, among others, that we’ll explore in-depth, is the relationship between the direct sound of a loudspeaker in a room and the room’s reverberation.
Prof. John Vanderkooy presented an AES paper offering analytical proof and compelling evidence that the acoustic center for low frequencies resides in front of the loudspeaker at a distance of approximately two-thirds of the baffle radius.
"If a battle can't be won, don't fight it"
- Sun Tzu -
Whenever we experience too much of a particular frequency or frequency range, we're tempted to resort to equalization to resolve the situation. In this article I will demonstrate that the effectiveness of EQ relies entirely on the relative level separation from other sources.