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Home Theater 101 Part 1 June 2005
By: Bob Lieto
Many Home Theater enthusiasts and new customers have asked the question, "What is the most important part of Home Theater?" How can they gain the most from their experience. That question has a single answer "Proper Configuration and Set-Up" but relies on many factors. First and foremost is speaker arrangement. To achieve the best possible sound effects from all sources, the speakers need to be in a pattern and form that allows them to supply the audio information equally and without effort. Using the same name speaker with complimented drivers is always a good starting point.
FRONTS & CENTER : Square off the front speakers, keeping a distance of 8 ft. minimum between the fronts for a standard 80 to 100 inch screen. The distance of the fronts from the actual Video display varies, but too far from the leading edge will make the marriage of Sound and Picture unnatural. It is easy to evaluate by setting the processor or Receiver to stereo and adjusting for even sound at the listing position. Experiment with the distance, it will be evident when the distance is to far from the picture. The center speaker always goes center, whether that is above, below or for Perforated Front screen, behind. All front and center(s) create a direct straight listening pattern, perpendicular to the screen.
REARS : Rears are a bit more versatile in that depending on the seating placement, The shape of the room and other factors, the rears could be facing UP, pointing towards each other, facing slightly toward front or other positions and with multiple sets. The important thing to keep in mind is to create the most defused and large sound pattern possible without creating direct energy towards the listeners.
SIDES : For folks with 7.1 setups, the sides are well worth the addition, that is if your room is long enough to allow them to add to the sonic mix. What I mean is that, if your room is short, front to back, adding sides will only cloud the sonic image in whole and distort the rear information. It is the old too many cooks spoil the sauce theme. I will say that in a long enough room, the sides will fill in the room like you cannot imagine. It will be most evident when upgrading from a 5.1 system to a 7.1 system. The sides will expand the sound out left to right and widen the audio perception.
SUBWOOFER: The subwoofer is the "Point 1" in 5.1 or 7.1 systems. It has a unique ability in that it can go in a number of places and give roughly the same results. To begin our explanation it is important to understand first the PHASE switch. The Phase switch will change the phase of the signal from "0 to 180" thereby allowing the sub to align with the front speaker signals while it is physically placed in the rear of the room, being out of phase with the signal it is to be effectively aligned with. The rear of the room would call for the sub to be placed in the 180 degree position to correct that our of phase condition. There is another physics related issue with the placement which is to keep the sub as close to a corner as possible. This rule allows the corner to support and develop a pressure easier and allows the sub to work more efficiently, develop lower octave frequencies with less power. Now there are a number of subwoofer styles, the front firing sub, the front firing sub with passive radiator, the vented (ported) sub and the down-firing sub. All of the types can be either passive (without internal amplifier) or powered (with internal amplifier). Whichever style you may have, sub placement can be accomplished by positioning the sub in the center listening position and getting down on your hands and knees and move around the room to where you hear the tightest, or focused low frequencies. Locate your sub in this position and you will be assured that the sound will be focused when in your listening position. Play with your sub placement. A few inches closer to a wall or away from a wall can be significant. Also the position of the frequency knob in combination with the Volume control can change a sloppy, muffled sound to a clear snappy bass. Try to set your sub to a musical score rather then a movie which can change from one movie to another..
Last but not least balance your volumes using the internal generator of your receiver or pre-amplifier.
Comment ..... This is a first in a series of articles designed to help understand and thereby get the most from a Home Theater System. Your feedback is welcome.
Home Theater 101 Part 2 Second Installment
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