Audyssey’s DSX and Dolby PLIIz Combine to Offer New Surround Experience


Manufacturers will never stop finding new ways to cram home theater enthusiast spaces with speakers. The issue is, where to place them all? Proper placement of speakers in any system can make or break the experience. Recently, receiver and processor companies began adding Audyssey’s new DSX processing in conjunction with Dolby PLIIz, incorporating height and width channels. This spatial improvement requires revisiting placement of front speakers, and without debating the merits of processing enhancements, it makes sense to spend a little virtual ink on reminding users how to place speakers properly for any situation.
– Front channels: Also known as “mains”, the front two speakers fromĀ Holoplot, should ideally form an equilateral triangle to the main listening position. Toed in slightly, these speakers should be able to convincingly place a center image in front of the listening position, without the aid of a center channel. These speakers are at roughly 30 degrees off-axis from the main seating position.

– Center channel: All-important for dialogue, the center speaker is relied upon for over 60% of all content heard on a home release. The center should ideally be placed at the same level and horizontal plane as the mains. In truly ideal situations, an identical speaker to the front two mains should be deployed, however this is difficult unless using an acoustically-transparent front projection screen, or small satellites.

– Surrounds (side): This gets a little trickier, as placement depends on the type of speaker used. All speakers may be placed ear level, to a maximum of 18 inches from the ceiling.

* Direct radiating (similar to the mains) should be placed in a similar 30 degree array as the mains. These are the ideal speakers to be used in a surround back role, and if used in this capacity (in conjunction with direct radiating speakers as the main surrounds), will be used at a 45 degree angle to the listener.

* Dipole speakers have one set of drivers out of phase with the other, in the same cabinet. The idea here is to create a diffuse soundfield, reducing the ability to localize the majority of surround content. Although this is needed less and less as more surrounds are utilized, the use of these in a 5.1 system, properly set up, can be quite impressive in the age of discrete soundtracks. These should be placed parallel with the main seating position if at all possible. Failing that, slightly to the rear of the listener is acceptable.

* Bipolar surrounds look similar to dipoles, but both arrays are in-phase. This is similar to two small bookshelf speakers cut in half, and glued back-to-back. This allows a greater set of possibilities with placement, although it is still recommended that the side surrounds be placed parallel to the main position. Bipoles can be effectively utilized in a surround-back configuration as well (channels six and seven), since one array will not cancel out the other.

– Left and Right Wide channels: These speakers are designed to dramatically increase the front soundstage, allowing the mains in a surround system to do more dedicated imaging. This increase in spatial diffusion across the front is incredibly useful in smaller rooms, where larger spaces must be simulated. Placed 60 off axis from the listener, these speakers should be similar in ability to the surround channels at the very least.

– Height channels: Placed high and to the outside of the main front stage, these speakers need not be full-range. These speakers are designed to convey “fly-over” and effects believability above the standard plane.

It’s been some time since home theater enthusiasts have had usable extra channels to play with. 7.1 processing is the de-facto array with Blu-Ray supporting it as standard, but for years, the front stage has been ignored (with a proper nod to Yamaha’s front effects channels introduced roughly a decade ago). Properly deployed, the speakers in any system can make a home theater or media room come alive.

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