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LFM-1 Design Considerations

The Outlaws have always had a keen interest in proper bass reproduction. Starting from our first receiver, the Model 1050, and continuing into our Model 950 preamplifier processor we have always been committed to offering extremely flexible bass management for the widest range of sources.

Recognizing that not everyone who needs proper bass management would purchase one of our receivers or processors, we developed the ICBM (Integrated Controlled Bass Manager). This unique product has become the home theater industry's reference standard for outboard bass management when neither the player nor receiver/processor offers built-in bass management on the multi-channel analog connections.

Our desire to deliver proper bass reproduction led us to the decision that the time was right to design our own Outlaw subwoofer, a product that we would be proud to have in our own homes

However, being the Outlaws, we set the bar for this product very high:

1. The subwoofer had to be able to play deep bass, while still being able to reproduce movie soundtracks or musical selections with complete authority. This had to be achieved without resorting to a design that overemphasized any one-frequency band. This is a distinct departure from the designs used by some manufacturers, who, in an effort to wow their customers use this one-frequency band approach, which lends itself to "one note bass". These systems, no matter how subtle the signal is, will invariably growl with the same annoying frequency.

2. The subwoofer had to play at substantial volume levels, no matter what type of "main" speakers would be in use. This would ensure that the main speakers could not "outrun" the subwoofer.

3. The subwoofer had to be compatible with the decor in any home. However, at the same time the aesthetic concerns could not interfere with the system's performance. In other words, considerations such as cabinet size had to be dealt with in a way that would satisfy both the need to move enough air to deliver deep bass, without dominating the room to the point that the "non-audiophile" in the family objected.

Several of the Outlaws have a great deal of experience in developing speakers in general and subwoofers in particular, and as a result we are familiar with the best speaker technologies and designers in the industry. With that in mind we decided to complement our own knowledge with that of an outside expert, Dr. Poh Ser Hsu. As one of the world's foremost subwoofer experts, we have always admired Dr. Hsu's designs. In fact, on more than one occasion we chose his subwoofers to demonstrate our electronics.

Dr. Hsu graciously accepted our invitation to consult with us on our subwoofer design. After much discussion and experimentation with drivers, crossovers, cabinet designs and system electronics we jointly developed our basic design approach for the LFM-1. The results of that work are as follows.

Dual Ported Down-firing Design

We decided to place the "business end" of both the driver and the ports on the bottom of the cabinet. This approach would net us two significant benefits:

1. No placement restrictions. Downward firing designs ensure maximum placement flexibility while rear or side-firing designs tend to limit your options by requiring that the cabinet be placed away from the wall.

2. The elimination of audible-port turbulence. Dual, down firing ports dramatically reduce the unwanted whistling that is heard when air exits the port on side or rear firing designs. While flared ports may help to reduce this effect, only a downward firing design can virtually eliminate it. EFFECTIVE 25 HZ DESIGN Our goal was to deliver a subwoofer for less than $600 that performed as well with music as it did with movies. This required reasonably deep frequency response and powerful output, while maintaining precision driver control. We resisted the temptation to design a subwoofer with output to 16 or 18 Hz, in favor of a design that did not compromise SPL or raise distortion. To the Outlaws, real world performance was more important than "bragging rights" to a specification that would not deliver a real benefit. We decided on a 25 Hz design after lengthy discussions with Dr. Hsu. He proposed that 25 Hz provided the best overall audible performance. While we were initially surprised at this recommendation, Dr. Hsu pointed out that when customers have the ability to adjust port frequency, 25 Hz was the most frequently chosen setting, regardless of the capabilities of the system. The reason for this is simple: 99.9% of all deep bass (in music and movie soundtracks) never goes below 25 Hz. Since this setting means that no low frequency would ever be perceived as missing (and of course the physical component of deep bass response would still be there) we capitalized on this design philosophy to develop tight accurate bass response. At the end of the day, Dr. Hsu was correct. Our listening tests and yours will bear out the fact that an optimized 25 Hz design is far more important than simply being able to claim 18 Hz reproduction.

Cabinet Aesthetics

After discussions with designers and architects regarding the color of the cabinet, we determined that the most appropriate approach for the LFM-1 is a painted black satin finish. This color and finish will fit almost any interior without clashing with existing furniture and surroundings. To break up the solid surface of the cabinet we added a smoked Plexiglas inset panel on the top of the cabinet. In the final analysis we feel that the design, performance and price of the LFM-1 has achieved our goal of providing you with an exceptional subwoofer. The LFM-1 represents the best subwoofer value in the industry, and when you audition yours we are confident that you will reach the same conclusion.

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