believe the PH715 is loosely based on Nexo's PS
Series loudspeakers. The asymmetric is from the
different coverage pattern above and below the vertical
axis of the horn. The lower half of the horn has
a wider dispersion (100 degrees) whereas the top
is narrower (50 degrees). Due to this asymmetry,
the lower half is used for nearfield and the top
half, being narrower, for long throw.
axis response is quite impressive. Pretty smooth
with a constant roll-off. In auditioning this horn,
the horizontal off-axis response sounds superior
to the Dayton HE07E.
Black trace in Fig 1 is of the PH715/D220Ti combo
with the Synergy crossover set at 1kHz (18dB/oct).
It appears it's possible to cross at 1,200Hz - 1,500Hz.
Red trace is with the crossover at 1,750Hz. I opted
for this frequency because the D220Ti is very comfortable
with it. No strain at all.
Violet trace is with the addition of an 8.2uF capacitor.
This capacitor has dual purposes.
it corrects the attenuation. The response is virtually
"flat" up to 10kHz.
also offers some protection to the compression driver.
Whatever small DC offset that may appear at the
output of the power amplifier will be blocked by