Wavefront shapes?

[moldyoldy]

Hoping someone can enlighten me or offer a reference on the interaction/integration of differing wavefront shapes. For example, can a spherical wavefront from a tractrix horn integrate well with a planar wavefront CD horn? My backwoods logic says there'd be an increasing phase discrepancy as you move off axis.

Also, what feature(s) determine the type of wavefront produced by a given xdcr?

[Hoerninger]

Also, what feature(s) determine the type of wavefront produced by a given xdcr?Moldyoldy, mainly it is defined by dimensions. With increasing frequency a circular piston will produce a circular wavefront until the wavelength equals piston diameter. Then starts beaming. By using a small piston within a circular baffle take the diameter of the latter.
With piston breakups, willingly or unwillingly, the dispersion at higher frequencies can be widenend.


For example, can a spherical wavefront from a tractrix horn integrate well with a planar wavefront CD horn? My backwoods logic says there'd be an increasing phase discrepancy as you move off axis.Your logic is right. For speakers this combination is not good. The only point for rehabilitation is, that at distances long compared to the speakers dimensions changing phase can be neglected - long throw PA but not at home.


Hoping someone can enlighten me or offer a reference on the interaction/integration of differing wavefront shapes.There is an interesting AES print "Improvements In Monitor Loudspeaker Systems" by Smith, Keele and Eargle (here in LHF Technotes), which opened my eyes concerning power response and off-axis response. It is said that it is good practice that at a given dividing frequency the directivities of both speaker are the same. This can be achieved by a woofer with a controlled directivity, so not any woofer will do.
After reading this I have understood JBLs traditional two way concept much better.
___________
Peter

PS: Kyrill did not hit northern Germany too strongly besides that people at the coast are used to stormy weather. But all over Germany main train traffic had stopped from thursday to friday.

[moldyoldy]

Thanks a lot Peter! I've read the AES doc you referenced, but was looking for something else at the time, so I'll review it again.

"PS: Kyrill did not hit northern Germany too strongly besides that people at the coast are used to stormy weather..."

An obvious lesson that many living in US coastal areas have obviously forgotten, particularly those at sea level or below. "Blown away" is definitely a context-sensitive phrase.;) Glad all is well!