We recommend using bipole/dipole speakers for the surround channel speaker locations in serious, dedicated home theater installations. The immersive effect that these speakers produce is an improvement compared with the surround effect produced by less expensive options such as traditional bookshelf speakers or in-wall/ceiling speakers. The Case for Bipole/Dipole Speakers:
Many audio aficionados champion the idea that the best sound for the surround channels is achieved with speakers that produce a wider more dispersed sound field than that which is achieved with a standard, more directional monopole speaker. As with all things related to sound preference, the benefit that you will hear
is relative. For some audiophiles, the difference, no matter how small, is worth pursuing. For the more casual listener, the added cost or simply the inability to “hide” the speaker as you can with an in-wall or in-ceiling speaker is enough to make the purchase of bipole/dipole speakers a non-starter.
In home theater, you have three, mostly directional, speakers in front that together create a soundstage or "wall" of sound. In stark contrast to the three speakers in front, you have only one speaker to the right and to the left (the side-surround speakers). The challenge is for this single speaker to create a sound field that is wider, more similar to the front, versus a perception of sound from a single point.
In large cinemas, you’ll notice many speakers along both the right and left wall. Primarily, this is to provide more even sound levels for the entire audience, but it is also used as a way to create a wider, more dispersed soundstage for the surround channels. In most home theaters, there is neither the space nor the budget for multiple side/surround speakers. That said, you can create a similar, more diffuse surround experience, through the use of speakers that do not directly point at the audience.
Possibly the best way to achieve this effect in limited space is through the use of bipole or dipole speakers for the surround speaker locations. Bipole and Dipole speakers help to create the illusion of a bigger, wider room where the surround sound information seems to come from all around the listener. The result is a more immersive effect with what is occurring on the video screen and a smoother transition with the sound field created by the front speakers. Which is better- bipole or dipole?
Bipole speakers create the effect by firing the drivers in different directions simultaneously. Dipole speakers create the effect by firing the drivers in different directions but 180 degrees out of phase. Check around the internet and you’ll find many strong opinions over whether bipole or dipole creates the better experience. A general rule of thumb, of which we happen to agree, is that dipole tends to create a better overall effect for movies and sporting events, whereas bipole is better for multi-channel music. The bottom line, however, is that for most people both setups create a better effect than do monopole speakers. We let our customers make up their own mind by designing our speakers with a simple bipole/dipole switch. Speaker Location:
Bipole/dipole speakers usually work best when installed on walls directly across from the primary listening area. This places the listener in a sound "node" allowing the sound waves to be heard more from around the listener as opposed to directly at him.
For the back surround channels (found in 7.1), timbre-matched monopole speakers or the same bipole/dipole speakers used for the side surround locations can be used. Most professional installers that we know prefer to use the exact same speaker for both the side surround and the back surround channels, i.e. if you choose to use bipole/dipole speakers for the side surrounds, use them in the back as well.