MTM (Midwoofer-Tweeter-Midwoofer)

MTM configurations such as the PreSonus Eris E44 and E66 feature two midrange drivers that cover the same frequency range, with a high-frequency driver nested between them. Because the two woofers cover the same frequency range and are placed so that their acoustic centers are less than one wavelength apart, the combined signal of the two drivers propagates forward as a single waveform. This provides a much more dynamic output than their relatively small size would normally afford. The two woofers also work to partially contain the dispersion of the tweeter, minimizing phase displacement. This results in smoother frequency response and an ultra-wide, detailed stereo soundstage.