Sorry if I "Horn In" to your thread...
Quote:
Originally Posted by
toddalin
In accordance with the theory, the plates have to be less than 1/2 wavelengh spacing. I used 0.35", similar to JBL, that takes it over 19kHz..., higher than the 075 can go.
For the size, I used the HL-91 lens dimensions, but scaled them to the the diameter of the tweeter rather than the horn throat.
OK, the HL-91 or a flat-front biradial or a CD horn are the acoustic "transformers" to match, within physical constraints, (horn diameter and length) the diaphram's acoustical impedance with the air mass of the listening area.
For example, excluding the crossover network, the mid-range subsystem of the JBL 4350 Studio Monitor :
Midrange Driver: 2440 2" Compression Driver
Midrange Horn: 2311 2" Short Exponential Horn
Acoustic Lens: 2308 Slant Plate
Point being, in the midrange subsystem cited above, the 2440 compression driver "needs" the 2311 short exponential horn for impedance matching, and "needs" the 2308 slant-plate lens for impedance matching and to define the horizontal and vertical pattern characteristics.
But the 2402 and 2405 ring radiators are designed and manufactured with their acoustic impedance matching and pattern control built in, by way of their throat and phasing element geometries.
My question is, what will be the effects on the horizontal and vertical patterns due to the interaction of their intrinsic elements, and the slant plates? A lens is a lens. Something(s) will change. I know it can be worked out mathematically
and I wish I had those skills but do not.
How else could one predict the outcome? I think your RTA equipment will tell the tale. Ultimately, how will it sound ?
Regards, -D_E-