Three-Way System
Unlike similar conventional systems, the UPM-1P and UPM- 2P loudspeakers are three-way systems. In the pass band below 320 Hz, where greater power handling and cone area are needed, the 5-inch drivers are driven together in parallel. However, above 320 Hz a high-pass filter rolls off the signal going to one of the drivers, so only one of the two drivers reproduces the critical mid frequencies close to the crossover frequency. Since power requirements are drastically lower in this region, there is no loss in response. and a remarkably uniform response at all frequencies along all axes — horizontal, vertical, and diagonal.
Note
In conventional two-way designs, both low-mid drivers reproduce the same information throughout their operating range. At low frequencies, this is not an issue, since the wavelengths (500 Hz, about two feet) are longer than the distance between the center points of the two cones. But at around 1 kHz, problems arise in the off-axis vertical response of the system. As the wavelengths of critical mid frequencies approach the distance between loudspeaker centers, significant comb filtering effects appear. These “holes” can be quite severe. In applications where such a loudspeaker is mounted vertically and the audience area is contained entirely within a 50-degree vertical arc, sharp off-axis attenuation may not be detrimental. However, if you flip the cabinet on its side to use it as an under-balcony loudspeaker, you will experience serious difficulties.
The UPM-1P and UPM-2P loudspeakers provide a more elegant solution, with an active crossover distributing the signal between the low- and high-frequency sections, and a simpler 2-way passive crossover that is employed to implement the single-point midrange solution. In addition, a sophisticated phase correction circuit in the active electronics compensates for phase shift in the passive network. The result is a significantly better system impulse response, and better imaging when UPM-1P and UPM-2P loudspeakers are used in stereo or multi-channel applications.