GREAT ROOM CORRECTION
The companies that do room correction the best are the companies that have been at it the longest with the most expensive gear. Lyngdorf, Meridian, Tact, DEQX and Rives are about it for the elite of the resonance tamers.
But there has been a great deal of progress in this field in mass market products. Courtesy of Audyssey room correction, this capability can be installed in mid-fi receivers for just a few dollars. This greatly lowers the bar for admission to the benefits of room correction. Not only is the basic capability accessible, it is now of a very high sonic quality with no perceptible loss in transparency to offset the gain in smooth response and phase correction.
Room correction will not make up for a terrible room or a very poor placement of speakers or bad speakers but it can make a well thought out system sound excellent.
At this point in time, room correction has crossed the threshold from being a costly crutch for a bad stereo system to being an asset to any high fidelity sound system regardless of cost.