I came across this commentary on the use of Dipole speakers as surround speakers, and thought it would be of interest.
Before we begin, please note that I don't necessarily agree with this person's argument--I'm merely using it as a discussion spark.
From
www.adnm.com in the "Advice" section.
In reply to:
A word on Dipole Speakers
Nothing infuriates me more than blanket recommendation of dipolar speakers with no serious discussion of their limitations and flaws. Dipole speakers were designed specifically to hide the poor rear channel sound of Dolby Pro-logic surround. In Pro-Logic, the rear channels are monophonic and extremely low fidelity, essentially equivalent to AM radio. The thought was to make take the monophonic sound and spread it across the back of the room to make it more spacious and less noticeable. However, with the advent of 5.1 soundtracks with essentially CD-quality stereo rear channel sound, spaciousness is dramatically improved and, because of the dramatic improvement in quality, there is no reason to hide the rear sound any more. And, with the ability to further split two rear channels into three, precision and spaciousness are enhanced to levels no dipole speaker could possibly match. Interestingly, dipole speakers are the most difficult to setup because there is only one way to set them up at all - directly to the side of the couch, several feet above the listening position with the couch 5-10' from the back wall. Any deviation from that setup yields even lower quality rear channel sound. Also, many proponents back dipole speakers because "it mimics the more diffuse sound of a movie theater." This is like buying a sports car that performs like a bus. Movie theater sound is awful compared to a good home theater system. More to the point, sound engineers use two or three discrete directional speakers behind them, not dipoles. If you want to hear what the sound engineer hears in his mixdown studio avoid dipole loudspeakers at all cost. Movie theaters sound the way they do because they have to play decent sound to hundreds of people, where as a home theater can focus its performance on just a few people. Also, many dipolar proponents insist that dipolar speakers are less noticeable and allow you to concentrate more fully on the TV screen "as the director intended". But they don't know what the director intended.. Dipolar sound is an "effect" that seriously modifies and dilutes the sound of the rear channels. Only true monitor speakers allow you to hear exactly what the sound engineer heard when he mixed the soundtrack. If he mixed for a diffuse effect, that is what you will get. If he wanted an intense, distracting effect, that is what you will get. If you own dipolar speaker and want to understand more of what I mean, hook them up to the stereo front channels of your receiver and play stereo music through them. If that doesn't convince you of the low fidelity of dipolar speakers, I don't know what will. Although I could go on forever on the dipole subject, I can say that we have switched dozens of people out of dipolar rear speakers purchased elsewhere because the customer simply did not get the performance that he had expected from their new DVD player. All of them are extremely happy with the far more accurate and intense surround sound of high quality monitor speakers.
This editorial contains way too many absolutes for my tastes, but I think there is some substance to the argument. It seems that this discussion is relevant to all multipole applications--not just dipole. What do you QS fans think? How about those using M2s, M3s and others for their surrounds? I especially invite some commentary from Alan on this subject.
