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Old 30th January 2019
  #48
Gear Maniac
 

Quote:
Originally Posted by RyanC View Post
The term 'near field' actually means the sound source is inside the critical distance, which is the point in a room where the SPL of reverberant energy is equal to the direct (in sum, not peak).
Your definition of the term "near field" as it relates to critical distance is indeed how it's used in some cases, but is not the only valid definition/use. (IMHO would rather be more clear to refer to as "direct field.")

"Near field" as it relates to speakers and perception is defined in geometric terms. Geometric near field is defined as that region close to a source where the sound pressure does not vary as the inverse of the distance from a source.
"Near field" can also be used in the hydrodynamic sense, where particle velocity and acoustic pressure is out of phase.

More relevant to the current subject, "near field" listening is an issue with speakers with significant driver displacement due to 1)the angular separation between drivers enabling the ear-brain to localize individual frequency bands and 2)off-axis positioning of the listener to one or more drivers.

Speaker lobing between two drivers that you've linked in another post is a separate issue.
Quote:
Originally Posted by deedeeyeah View Post
of course every speaker has more directivity towards higher frequencies but just after a few centimeters, the 'beams' overlap/combine: you are getting the same sound at your chosen listening position, regardless of what crossover settings a manufacturer came up with.
Not so, the "beams" do not "overlap/combine" in a predictable fashion in the geometric near field, and certainly not in just a few centimeters away from a 2-way speaker.
Quote:
thx for the hint on some non-horn coax designs - i cannot agree on your comment on horn-loaded speakers though: while i luv danley speakers for luve mixing (and it's a shame that they are not getting more attention in europe), i'm pretty much sure they don't measure or sounds nice a short distance - and they don't have to: the purpose of a horn is to 'steer' sound and to get some throw capacity so they perform well at some distance!
Horn or no horn, coax designs exhibit less geometric near field issues than speaker designs with driver displacement. (Good) coax speakers can produce very close to its far field response at close distances. It should be self-evident why given the above explanation of issues regarding localization of bands and off-axis positioning.