THX advantages
THX is merely a set of specification guidelines. In most cases it raises the bar of excellence within a component and, in the end, produces a more rugged piece of equipment able to take the punishment of a home theater.

This is not to say that a non-THX speaker can't handle the demands of home theater. This is far from the truth. Again THX is a set of specifications to follow. Just because a speaker is THX certified does not mean it will sound better than one that is not.

The THX specification ensures that the speakers will be able to produce all the high and low frequencies while retaining clear and crisp sound. By controlling all aspects of sound reproduction THX is supposed to bring you very close to what the director intended you to hear.

THX Disadvantages
There are disadvantages to using THX speakers. The sound of THX speakers tend to be beamy and highly localized. The reason for this is that since the speakers are located behind the screen in movie theaters, they need to be extremely directional so what you see on screen matches the audio you hear. In a home theater this is almost always not the case. The left and right speakers almost always flank the sides of the TV with the center speaker used to attach sound to the screen.

This beamy, localized sound is great for movies, but not stereo listening. It's a safe bet that all home theaters also double as the main music system.

The problem with THX speakers sounding beamy is that it goes against the qualities you should look for in a good set of music speakers. Music speakers that sound the best have and open sound-stage that envelopes you in 3-dimensional sound. With great stereo speakers you shouldn't be able to hear (localize) the main speakers at all, but rather just hear the music that's being played.

All but the most expensive THX systems cannot produce music on the same level that non-THX speakers produce. THX speakers use duplicate drivers (such as two tweeters) that produce a beamy localized sound that simply doesn't cut it for music listening.

The Manufacturers Choice
There are a number of reasons speaker manufacturers choose not to go THX. Many have done their own research and development, and feel that the THX logo on the speaker shadows the work they've accomplished to produce great sounding audio speakers.

Another reason is that many high-end speakers can already handle the specs THX lays out, and have thus decided that spending extra money to get the THX logo on the grill won't help them bring a better speaker to the consumer. Instead it would just raise the price.

Are THX speakers for you?
If you're into watching movies only, have a dedicated "movie only" room, and are interested and getting as close as possible to what the director intended, then by all means THX speakers are for you.

A THX home theater almost automatically makes you buy the better gear and, as with anything, you pay for what you get. The best advice is not to get caught up in the hype and let THX certification sway your decision when comparing speakers.

When comparing speakers, ask yourself which speaker sounds better for you, and if it has the sound qualities that you desire. Remember it's your home theater, and you should purchase only the items that you like. Not what some techie says should sound good. Buy speakers based on sound quality, not a logo.