I’d say about ten milliseconds. The difference in sound, that is. Say them both out loud. The very first ten one-thousandths of a second is all that delineates the letter “t” from the letter “c” to our ears. Often as we age we have less ability to recognize higher frequencies. We may also lose our perception of higher frequencies due to other factors, like simple genetics or from being exposed to very high levels of sound. Any distraction could then blur the difference between cake, take, sake, flake, bake, make, etc. Context is what normally gets us through those moments, but that is true only if one heard and understood the preceding lines.
It is imperative then to keep sound on the audience and to keep sound off of everything else, thus minimizing reflections. Proper speaker alignment is critical so that the speakers may work coherently and not introduce their own anomalies into the environment. We must strive to choose the correct tools and educate our client on how best to use them. We must ensure room to grow and adapt so that our creations do not become obsolete.
These are our goals. This is our expertise. Your sound system is the most obvious interactive utility you employ. Let Robert Mark Audio design it professionally.