DON'T DAMN THE DOMAIN -- TIME IS ON OUR SIDE

Waveguide and inter-driver time domain alignment are optimized. Seeing that edge diffraction is virtually eliminated, all of the tones that emanate from the waveguide appear to originate from the same point in space. This results in a coherent wavefront with respect to frequency. Such coherency preserves the time dependent information encoded in the recording. This vital information is the source of the spatial "cues" that the human brain uses for the localization of three-dimensional sound images. If this information is altered or masked by distortion, then the speaker's ability to produce a convincing illusion of three-dimensional space is impaired or even destroyed.

The preservation of this information is enhanced by the fact that the waveguide provides a natural high frequency driver "set back" to help bring it in time alignment with the energy emanating from the woofer. Many designs have attempted to do so by providing a stepped baffle that locates the tweeter at a point further away from the listener than that of the woofer. While such techniques do provide some level of success in this regard, it is only effective "on-axis" at a point perpendicular to the baffle plane. The effect is virtually destroyed at angles moderately off horizontal axis. In fact, the resultant erratic dispersion and degraded inter-driver response summing off-axis often negates any real benefit. The designer would be wise to simply mount the tweeter to the same baffle plane as the woofer and accept the compromise.

The reason a waveguide does not suffer the same loss of driver alignment off-axis is that the expanding wave is forced to follow the surface contour. The path length of the expanding wave remains virtually the same at all angles off-axis within the coverage area of the waveguide.

The upshot of all this is that SP Technology Loudspeakers products offering waveguide technology have few equals with regard to sound stage and three-dimensional imaging. Electronic "gadgets" or DSP processing is not required to reproduce a natural and enveloping sonic illusion of 3-D space.