How do standing waves and resonance relate in a speaker?

[Born2bwire]

Do you have any idea on how ka values can change the wavefront pattern in the near field. Going through the basics on radiation from vibrating sphere , it seemed to me that the wavefront pattern in the near field may turn into a plane wavefront depending on the ka limit and position of the reflector. Also I found a literature that mentioned that at high ka limit the node surfaces will tend toward planes in the near field.I am still looking into the literatures but I was wondering that you may also provide me some idea it.

I do not think that we can make any generalizations on how the near field will behave without taking into account the structure and geometry of your sources. At least in electromagnetics, the near field can vary greatly depending on the type of antenna that you have. Perhaps with acoustics the types of sources are more uniform and one can make more accurate generalizations but I wouldn't know.

 

[SFB]

Why wind instruments are asymmetric?Is this a condition to get a strong standing wave ?What about a flute? Is the cylindrical enclosure helping somehow to store more energy.Also , I would be interested to know about wave propagation characteristics in the near field (fresnel zone). As it seems to me from huoygens -fresnel principle that its the zone where constructive a/destructive interference occurs for the waves radiating from each point of the source. So should I consider fresnel zone as a region where the shape of the wavefront for the entire source is established and far field as the zone where this wavefront starts to radiate.What is the condition (not the mathematical formula that calculate the near field length) when the wavefront starts to diverge.

Also , I found a graph that shows that the pressure is not inversely related to distance in the near field. For a plane source , the pressure rather remains constant very near to the source.