Atlantic Technology 224 SB, 444 SB Placement and Operation, System Set Up, How Much is Enough?

8 Placement and Operation

Model 224, 334 and 444 SB Powered Subwoofer

Placement and Operation

Generally speaking,the best location for your new subwoofer is the front of the room,close to a corner (Figure 5).Every room has its own unique sound characteristics, and flexibility in the exact placement of the sub- woofer is always desirable. The closer the subwoofer is placed to a wall and especially a corner, the more and deeper the bass response you will hear.Because of an acoustic phenomenon known as "room gain," a well- designed wubwoofer playing in an acoustically-favorable room may well deliver low bass deeper than its rated response.However,in some rooms, corner placement can produce a “one note” boomy effect. Under such circumstances the subwoofer may work better away from the corner. Experiment to find the best position in your room.

Helpful Hint: A particularly useful experiment is to place the subwoofer right at the prime listening position (move your couch or chair out of the way and put the sub in its place). Then play something with good bass content (preferably music), and walk around the room, listening to the subwoofer’s response. When you locate an area that has an ample amount of well defined bass,

you’ve found a good place to locate the sub.

Figure 5

Typical arrangement for a single subwoofer in a home theater.

1.	Start here	2. Move to
		corner for
		more bass
		3. Move away
		from wall for
		less bass

System Set Up

When setting up a complete home theater we strongly recommend that you use a Sound Pressure Level meter. Radio Shack® has a good one that is very affordably priced (approximately $50). To use this meter, turn on your system, put the Processor/Receiver in the Test Mode and set its main volume control to 0dB.Sit in the prime listening position,set the SPL meter to the 70dB scale, Slow Response, and C Weighting. Now, holding the meter pointed up and in front of you,let the system cycle its test tone from speaker to speaker and set every speaker to 75dB using the individual level settings in the Processor/Receiver. As tempting as it may be to set the subwoofer and/or surround speakers higher than 75dB, listen again after calibration and see if you can acclimate to these levels. Try watching several different movies and keep in mind that the goal is to have a system that sounds like you’re actually “in the movie.” When using the latest discrete digital electronics which include internal level controls for all channels,we recommend setting the front mounted Level Control to its Preset position and using the Processor/Receiver’s built-in subwoofer level control.

If you decide not to use an SPL meter try to set all the speaker levels the same using the Test Tones. Of course, this will be much more difficult without the meter, especially for the subwoofer.

Figure 6

Front Panel Variable Level Control located behind the removable grille

Recess and indicator for level adjustment

Preset Position

Indicator LED

Subwoofer Tuning Without an SPL Meter or Test Tones

Start your listening with the subwoofer Crossover control set at around 100Hz or in the Bypass position if you’re using a THX Certified proces- sor or one with a built-in crossover.Set the phase switch to Normal, and the front panel variable level control (Figure 6) to the Preset position. Play some music that you know has good bass content, and turn the level control up until you just start to hear the subwoofer working. Now, from your normal listening position, determine whether the subwoofer is playing loudly enough and filling in the bass frequencies of the music evenly. If adjustment is necessary, start by changing the setting in the processor or with the sub's level control if your processor lacks a sub- woofer level adjustment.

If the bass seems too ponderous, boomy, or heavy, no matter how you set the level, try moving the subwoofer away from the wall/corner. If the bass seems too thin, try moving the subwoofer closer to the wall/ corner.Small differences in positioning can make big differences in bass response.When you find a position that seems to work well, try switch- ing the phase switch between its two settings,listening particularly to the transition from the subwoofer to the satellites.

How Much is Enough?

Sometimes people prefer more bass impact for movies.Using the movie setting for music can result in overpowering and unnatural bass repro- duction.You may wish to determine both a video level and an audio level if you find yourself falling into this camp.Remember however, the most common error people make when setting up their system is to play the subwoofer (and surrounds) too loudly. Of course, the Home Theater Police will not arrest you for this act. But should you desire the most accurate overall reproduction, a well balanced sound from deepest bass to highest treble is the best way to get it. Have fun. Experiment. Enjoy.