Originally Posted by yuradar
Thanks for your suggestion. I will check into the spec of these two.
Is there any particular reason for direct radiating (InWall Silver/4 LCRs) for rear surround?
Dawn is correct that there are several schools of thought about the optimal directionality for surrounds. Many prefer the diffusiveness of a dipole speaker.
A Dipole has 2 sets of tweeters and mids, but neither of them is facing the listening position. When wired out-of-phase, they have a "null" in the axis facing the LP and most of the sound is directed to the sides of the speakers. It is then reflected off the room boundaries and the result is a very diffuse, spacious sound.
A Bipole is similar to a Dipole, but it is wired with the speakers in-phase. If the tweeters and mids have wide dispersion, bipoles can direct virtually as much energy into the axis facing the LP as they do to their sides. Bipoles usually sound more directional, but they still add a lot of diffusiveness due to their driver layout.
Monopoles have only one set of tweeter/mids and they are directed towards the LP. Therefore, they have a very directional sound with a high degree of localization.
So, how does one decide what speakers to use for the various speaker positions in a surround sound system? IMO, there are two primary considerations when making these decisions for the surrounds, (the mains are a whole different discussion and I don't want to get into the selection of monopoles, bipoles or dipoles for the mains):
1. The proximity of the speakers to the LP, and;
Proximity of the Surrounds:
2. The type of content primarily listened to.
If the surrounds are close to the LP, that will make them more directional. When they get close enough, the directionality of the surrounds can dominate the soundstage and overwhelm the listening experience. Definitely, dipoles
with their more diffuse sound will work better the closer the surrounds are to the listener.
If the surrounds are a little further away, bipoles
can be very effective at providing diffusiveness and spaciousness to the surround field while still retaining good directionality. (Some content works better with good directionality, but more on that later.)
If the surrounds are at similar distances to the mains, monopoles
can be used very effectively and provide all the spaciousness that the room needs.Types of Content:
Some content has all the ambiance and spaciousness it needs recorded in the soundtrack. Movies, and Multi-Channel Audio tracks have the ambiance needed by the recording engineer already recorded in the track. This content was recorded using monopoles speakers in the recording process and is *generally* best reproduced by speakers with a high degree of directionality, (monopoles or bipoles.) In movies, there can be things like gunshots, the sound of bullets whizzing by, birds chirping, pans of airplane flyovers, etc. These types of "discreet" sounds work best with directional speakers. MC Music can also have instruments recorded prominently in the surrounds. This is an artistic choice made by the artist and recording engineer. To faithfully reproduce those sounds, directional speakers work best
2-channel, stereo content can have ambiance recorded into the soundtrack, and when played back on a 2-channel system, that ambiance is reproduced by the 2 front speakers. If you want to use your surround sound system to play back 2-channel content expanded to "surround sound", you need to use one of the "expansion" modes, (Dolby PLIIx Movie or Music, DTS:NeoX, Neural, etc.) These are all "ambiance enhancement" schemes, and they don't provide any significant directionality to the surround sound. Non-directional dipoles work very well for that application. Monopoles can still work for this application, but they work best when they are further away.
Side surrounds vs. Rear Surrounds:
With "discreet" surround content, (7.1 content), recording engineers can place discreet sounds in the rear channels. They can also place "phantom" images in the rear/side channels that are meant to image in between those speakers. Directional speakers, (monopoles or bipoles), work best for those types of sounds. This is why most people prefer directional, monopole speakers in the rear positions. However, bipoles can work nearly as well, they can be used in BOTH positions and still provide directionality when called for and ambiance when called for. Unfortunately, if you want to use bipoles, you'll need to look outside of the Triad line, as Triad doesn't make a bipole. Personally, I wish Triad did make a bipole surround, as, IMO, a bipole is the best "jack of all trades" for surround duty, but that's just me.
I hope that helps.
CraigEdited by craig john - 8/16/13 at 9:04am