The MIT-800s in-wall bridge speaker transforms your smaller 2-way in-wall or satellite speakers into full range monitors. This compact, non-powered sub is not for replacing a decent powered LFE subwoofer, but to bridge the frequency gap often found when trying to pair smaller speakers to a high powered subwoofer.While typical compact 2-way speakers do a fine job of covering the high and mid frequency audio, they tend to taper off at the upper end of the low frequencies leaving a sonic gap between the highs and lows. You can adjust the upper end of your powered subs crossover to compensate, but that ends up sacrificing sound staging and depth of field as the directional upper low end frequencies start to collapse onto the location of your sub. Pair these with each of your main speakers for clearer, more well defined audio and wider sound staging. It will be like having massive full range tower speakers without sacrificing any living space.Please note that this video shows the specific instructions for installation ofPID 6317. While this speaker mounts into the wall much differently than the one in the video, the video shows the basic steps, tools, and types of procedures that would be used for the installation of any in-wall or in-ceiling speaker, and is included on this page for reference purposes only. Please refer to the specific installation instructions of the in-wall or in-ceiling speaker you have for the specific dimensions and installation procedures.