Listening To Music With ProLogic

Listening to music with Prologic is usually not a great idea unless it is has been mixed for use in Surround Sound (which is optimal). Though most music does carry out-of-phase information (usually ambiance) that Dolby Prologic can decode, results can run the gamut from "really nice" to "shut that crud off before I freak." However, I have found a way to use prologic with music that brings pleasing results a vast majority of the time.

In one of my receiver based systems (yes I have several surround systems in various rooms of home because, I am, indeed, a card carrying Home Theater Geek) I run two sets of surround speakers wired in parallel from the reliever. One set hangs from the ceiling in the rear corners of the room facing forward at 45 degree angles toward the listening area. The other set is mounted from the ceiling as well, but parallel along the sides of the room about half way between the front and back of the room. These are angled down toward the listening area also. I have found that using the two sets in this manner creates a better surround field than two point source monitors, and works just about as well as Dipoles (which you know I'm a big fan of from my previous article). Now that you know how I have these speakers placed, I will tell you how I use this Prologic system to get pleasant results with music.

The surround pair along the sides of the room is hooked up directly to the surround terminals of the receiver. The rear pair, however, is connected with the lever switches that I have mentioned above. In Prologic mode, I can engage the switches so that the receiver sends the left and right channel signals to both the front and rear corners of the room, while the side speakers reproduce the surround information, and the center channel does its thing as normal.

Most vocals in music are recorded at equal levels in both the left and right stereo channels, so that when Prologic is engaged, the vocalist usually takes residence in the center channel speaker (giving the artist center stage so to speak). Any patently discrete left or right information comes from the four corners (minus of course the previously mentioned center channel information), and the surround decoded ambience signal envelopes the listening area from the side mounted surround speakers.

When listening to music this way, I do have to raise the level of the side mounted surrounds slightly to balance things out, but the results can be really nice. In general, classical and live performances sound "livelier," pulling the listener in to the experience a bit more actively than plain stereo, while well mixed studio recordings open up a bit more, bringing increased impact.

There are caveats however. The noise floor of the sound system is raised slightly due to the active surround processing. Also, dynamic range on some recordings may suffer by becoming a bit more compressed, which can smear channel separation, transient response, and melodic accuracy. Finally, weird instrument placement in the sound stage happens from time to time, which could distract or delight the listener depending upon their mind set toward accurate recreation of musical performances.

Many of these are criticisms have been leveled at DSP (sorry Laurent) and other music surround modes as well, but the change from plain stereo is welcome much of the time, bringing a certain newness to well known recordings. It is not perfect, but let your ears decide before you judge too harshly. It is not for everyone, but if we all had the same tastes, life would be pretty boring.

I leave you with a small sampling of non-surround encoded CD's I have found work well in Prologic with the speakers set up as listed above.