S2 The Scattered Subwoofer System Two LFM’s

Owner’s Manual

S2: The Scattered Subwoofer System

If the actual +/- 3dB point cannot be obtained from the speakers’ specifications or the manufacturer’s web site, you can use the following chart as a guideline:

40 Hz Large tower speaker with one 12 or 15-inch woofer or two 10-inch woofers;

Small tower speaker with one 10-inch woofer or two 8-inch woofers

60 Hz Small tower or large bookshelf speaker with one 8-inch or two 6-inch woofers:

80 Hz Bookshelf speaker with one 6-inch or two 5-inch woofers

100 Hz Bookshelf speaker with one 5-inch woofer or two 4-inch woofers

120 Hz Satellite speaker with one 4-inch woofer or one or two 3.5-inch woofer(s)

Phase Switch

Depending on the absolute phase of your main speakers and amplifier, as well as the relative distance from the LFM Subwoofer and main speakers to the listening position, the bass in the crossover region may be smoother if you reverse the phase of the LFM. Try both positions of the phase switch to determine which way sounds more bass-heavy. The bass-heavier position is the setting where the output of the LFM and the main speakers are most in phase. Use program materials with bass in the crossover region such as music containing bass drums, double basses, bass guitar, etc., to determine the correct setting.

Port Switch

Depending on your bass preference, your Variable Tuning LFM Series subwoofer has two separate "tuning" modes. In Its “Max Output” mode your LFM series subwoofer will provide the greatest level of overall bass in regards to SPL (sound pressure level). In Its "Bass Extension" mode your LFM series subwoofer will provide the deepest bass (low frequency) levels. When using the Bass Extension mode you will need to ensure that the provided “port plug” Is blocking one of the ports located on the bottom of the subwoofer. In the Max Output mode, both ports should remain unplugged.

CAUTION: Do not leave both ports open when the Port Switch Is In the “Bass Extension” position as your subwoofer's performance will be comprised. If one of the ports is blocked using the supplied port plug, the Port Switch must remain In the “Max Output” mode. Failure to adhere to these requirements can lead to poor performance and damage to your subwoofer.

Volume Level

Using the built-in test tones of your receiver/processor, match the levels of all of your speakers including your LFM Series Subwoofer as described in your receiver or processor’s owner’s manual. A setting of 5 on the LFM’s volume knob should provide enough gain to properly match the sub level to your speakers. We recom- mend using an SPL meter such as the Radio Shack model (part number 33-2050). When using the test tones, measure from the listening chair and set the meter to the 75 dB level. In order to accurately measure levels between channels use “C” weighting and the “slow” setting.

Note that the Radio Shack meter is down about 12 dB at 16 Hz, 7 dB at 20 Hz, and 4 dB at 25 Hz. Add these numbers to the readout to compensate for these errors if necessary.

S2: The Scattered Subwoofer System (Two LFM’s)

Why Two Subwoofers?

In most circumstances two subwoofers will perform better than one. While you might assume this is for added SPL, the greatest benefit will actually be smoother bass response.

Room shape, the cubic volume of the room (width x depth x height), furniture, floor coverings and even wall and ceiling material all play a roll in bass per- formance. These factors create peaks and dips in the level of low frequencies at different points in the room. That said, two properly positioned subwoofers will distribute the bass throughout the room with greater accuracy than a single sub. For this reason many professional acousticians and installers recommend more than one subwoofer. The final result is that you will create a much larger “sweet spot” where the bass is powerful but more importantly smooth and consistent. If near perfect bass response is your goal, consider using two LFM Series Subwoofers: The Outlaw Audio Scattered Subwoofer Systems.

What’s Needed to Connect Two Subwoofers?

Most of today’s digital receivers and preamp/processors provide a single subwoofer output. Connecting two subwoofers to these systems is as simple as adding a Y- adapter. A Y-adapter splits a single output into two separate outputs. Be sure to use a Y-adapter that is of equal or better quality than the subwoofer cables you intend to use. (We recommend the Outlaw Audio PCA Y-Adapter.)

To use the Y-adapter, insert the single male end of the cable to the subwoofer output of your receiver or processor. On the opposite end of the Y-adapter you will now have two separate subwoofer outputs, one for each sub.

Placement and Level Control

Placement and level control of two subwoofers is somewhat more complicated than using a single subwoofer. However, the end result of two properly placed and calibrated subwoofers is well worth the added effort.

The procedure for placement of the second subwoofer is identical to that of de- termining the placement of the first subwoofer (see the “Subwoofer Placement” section of this manual). However, the second sub should be placed in the seating area outside of the “sweet spot” where good bass response is also required. Walk around the room until you find the area where the bass sounds the best, just as described in the process for locating a single sub. This spot will almost always be different than the one that was best for the primary sub.

NOTE: When calibrating your second subwoofer be sure to turn off the first sub. This will help you to determine ideal placement without being mislead by the response of the first sub.

When calibrating the final levels of each subwoofer, you may want to reduce their output to compensate for the added 3 or 4 dB of gain created by using two subwoofers together.

If you sense a loss of bass output after properly locating and calibrating both units in a two subwoofer system the likely problem is that the two units are out of phase with each other. If this occurs try flipping the phase switch on the back of one or both of the subwoofers until the bass returns. For more information regarding the phase control function, please read the “Setting the LFM’s Controls” section of this manual.

Outlaw Audio