Well, just adding components in the signal path isn't really the issue. Many components like resistors and amplifiers cause no significant delays relative to audio time scales. It’s the kind of components and how hey are configured that cause the "macroscopic" delays associated with EQ.
In order to filter a signal you need a circuit which stores some of the energy in the waveform then releases it some time later in such a way that it either with or works against the newly incoming parts of the wave. The fact that the circuit stores and later releases energy is what results in the delay.
Of course, the whole point of a filter is to act on some frequencies and not act on others. So, this storing and releasing of energy is not the same for all frequencies, therefore, the delay is not the same for all frequencies. Some frequencies experience almost no delay while others experience more after having passed through the filter. This especially causes problems when you try to add filtered and unfiltered or differently filtered signals together – i.e.
mixing.
Digital filters also create the same sorts of delays because they work on essentially the same principles as analog filters, except, it’s information about the waveform that is stored in memory rather than it’s physical energy stored in a circuit.
Hope this helps and doesn't confuse the issue more.
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By the way, this whole thing about the equivalency of energy in a physical wave and the information about the wave represented in a computer actually touches on some of the deepest and most profound questions in nature that physicists and philosophers are pondering today. In a certain sense one can argue that all events in the universe are really just exchanges of information and that the universe as a whole is driven to maximize the information it contains. Very cool stuff to think about if you're feeling bored some rainy afternoon.
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barefoot
