Ears are roughly 6 inches apart....a lot of phase correction is done when the brain combines both signals....so don't get too hung up on this issue alone, especially above 2Khz where our ears will quite likely get out of phase sound at certain specific frequencies anyway (depending on precisely where a person is seated...nobody keeps seated to within an inch position).
The lower mid range, however is an area that is more sensitive to phase issues....particularly the cross over from mid range to woofer in a three way design (two ways have an advantage here). At frequencies below 600 Hz the wavelengths are similar and then larger than the distance between our ears. Notice that at roughly 90Hz we completely lose the ability to locate sound. Misalignment in phase between two drivers in the lower mid can produce "comb filtering", a bumpy frequency response at the crossover and an "airy" unfocused sound; if male vocals lack the same focus as females then this may indicate a problem.
At 340 Hz the wavelength is around 1 foot; spatially speaking, mid and a bass woofer drivers that crossover near this frequency should not be more than a few inches different in distance from the ears (at least less than a quarter wavelength or 3 inches). This is rarely a problem if the drivers are mounted vertically....as the listener must go to extremely odd seating postions to have one driver more than even an inch different distance to the ears compared to the other driver.
Provided separate drivers are reasonalbly aligned in phase and spatially, most designers believe it is enough to have a smooth gentle phase behaviour over several octaves rather than preserve absolute phase (hence the preference for 1st order crossovers). Nothing abrupt. This approach is supposed to preserve the timbre/transient reponse of individual instruments by not smearing their partials with respect to their fundamental harmonics.
Active speaker designs have helped speaker manufacturers tightly control phase between separate drivers, gaining the advantages of separate drivers (less distortion, less beaming, less cone breakup, better dynamics and efficiency) whilst minimizing the drawbacks of having a crossover region.
The lower mid range, however is an area that is more sensitive to phase issues....particularly the cross over from mid range to woofer in a three way design (two ways have an advantage here). At frequencies below 600 Hz the wavelengths are similar and then larger than the distance between our ears. Notice that at roughly 90Hz we completely lose the ability to locate sound. Misalignment in phase between two drivers in the lower mid can produce "comb filtering", a bumpy frequency response at the crossover and an "airy" unfocused sound; if male vocals lack the same focus as females then this may indicate a problem.
At 340 Hz the wavelength is around 1 foot; spatially speaking, mid and a bass woofer drivers that crossover near this frequency should not be more than a few inches different in distance from the ears (at least less than a quarter wavelength or 3 inches). This is rarely a problem if the drivers are mounted vertically....as the listener must go to extremely odd seating postions to have one driver more than even an inch different distance to the ears compared to the other driver.
Provided separate drivers are reasonalbly aligned in phase and spatially, most designers believe it is enough to have a smooth gentle phase behaviour over several octaves rather than preserve absolute phase (hence the preference for 1st order crossovers). Nothing abrupt. This approach is supposed to preserve the timbre/transient reponse of individual instruments by not smearing their partials with respect to their fundamental harmonics.
Active speaker designs have helped speaker manufacturers tightly control phase between separate drivers, gaining the advantages of separate drivers (less distortion, less beaming, less cone breakup, better dynamics and efficiency) whilst minimizing the drawbacks of having a crossover region.