Horizontal Center Channel Speakers and Why They Should Be Avoided

[Big Daddy]

Originally Posted by drummerboy_2002

Ok, I'm back to my original confusion. How would raising the tweeter out of the mid array plane help with lobing? The issue is with two drivers playing the same frequency at the same time (the mids). The only place this would happen with the tweeter is in the small range where the crossover slopes overlap. Otherwise only the tweeter or mids are playing, not both.

Low frequency and high frequency sound waves have different radiation pattern. As a result low frequency drivers (midrange woofers) and high frequency drivers (tweeters) have intrinsically different radiation patterns. At the crossover point, the directivity of the drivers changes. Interference between the drivers at this point causes a dip in the level around the crossover frequency, with a peak above it. This will result in muddiness of the sound and movement of sound stage.

In reality, we have interference between three or more drivers, particularly at the crossover frequencies. Moreover, there is a significant interation between horizontal center speakers with the floor and the ceiling.

Remember that lower frequency sound waves have very long wavelengths and are omnidirectional and are not affected as much. The higher frequency sound waves have smaller wavelengths and tend to be more uni-directional with a much smaller soundfield. Interference in the upper mid-range frequencies up to and above the crossover frequency normally create most of the problems and damage sound clarity and imaging.

A vertical arrangement of the tweeter and midrange drivers will help imaging, clarity of the sound, and will increase vertical and horizontal dispersion. In addition, a lower crossover frequency point and a higher order crossovers network will help.