LOWTHER

Audio Vector Cabinet

Fiberglass horn removed. (photo)
Audio Vector has no crossover.
Both the PM4 and PM2 work as full range drivers.
To adjust the tonal balance between the PM4's high frequencies and the PM2's lows, a three Watt, 50 ohm slide resistor is mounted at the place marked in red.
The Two-Channel amplifier can easily run both drivers without the resistor.

The PM4 frame is enclosed in a wood case.
The PM2 back wave passes through both sides of the horn. The horn load begin at the place marked in blue.
The balloon looking unit is for use in horn loaded enclosures to keep the high-frequencies from cancelling. It has the same function as the phase plug for the non-horn loaded designs, but is shaped differently due to the different high-frequency effects of the horn.
It is designed to make better use of short horn effect.
The PM4 tone is extended by the ball; also reflected by the short horn and the rear wall of room behind the enclosure. Finally, it is added with PM2 tone.