Outlaw Audio home shop products hideout news support about
Topic Options
#34647 - 01/26/04 11:44 AM LFM-1 Design Considerations
Scott Offline
Desperado

Registered: 01/07/10
Posts: 673
We recently uploaded this information to the LFM-1 product page. I suspect that many of you will enjoy reading this:

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. For example, the Model 950 is the only processor in its price range to offer analog bass management on the 5.1 inputs for use with DVD-Audio and SACD players.

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:

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.
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.
The subwoofer had to be compatible with the décor 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:

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.
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.

Top
#34648 - 01/26/04 12:26 PM Re: LFM-1 Design Considerations
Raider Offline
Gunslinger

Registered: 11/30/02
Posts: 105
Loc: Cleveland, TN
As a new owner of the LFM1 I can say that you have achieved everything mentioned in this report. I have tower speakers in front that can get to 34HZ, yet the LFM1 works very well with them.
As far as looks, my wife had no problem with it because it was large enough to have a plant placed on top!. Now when you walk into the room the LFM1 looks like a stand that was made for the plant. That passes the wife test. However, I can't wait to make that plant do some "walking" of its own when the 25Hz starts kicking in.
So, I am very happy and glad I purchased this component after being "subwooferless" for many years.

How about considering a flat panel TV next!

Top
#34649 - 01/26/04 01:08 PM Re: LFM-1 Design Considerations
JMS Offline
Gunslinger

Registered: 02/15/02
Posts: 133
Loc: NE Ohio
Scott,

Your information is welcome and is congruent with my own early experience with the lfm-1.
Since my primary use of the sub is to play music, I was most concerned about the "musicality" of the lfm. The unit reminds me of the phrase, "Speak softly and carry a big stick." It reproduces the low end with authority yet it's not bombastic. (It will be interesting to play a bass-heavy dvd movie like one of the Star Wars pics to see how it copes with loud, low tones.) Right now, the limitation comes from the room my ht is in. If I crank the sub, things start sympathetically vibrating in a very disconcerting way. I probably will have to super glue all the furniture to the carpet! (Listen to the E. Power Biggs quadrophonic organ recording of the Bach Toccatas for thunderous pedal points!)

Oh, and one other thing. It passed the wife test. My wife can hear, and appreciates the extra realism when she watches the Dixie Chicks live in concert. (I recommend this dvd, too.)

Hey, and thanks for supplying us early adopters with the sub cable!

Jay

Top
#34650 - 01/26/04 01:13 PM Re: LFM-1 Design Considerations
JMS Offline
Gunslinger

Registered: 02/15/02
Posts: 133
Loc: NE Ohio
Interesting how both Raider and I independently refer to the "wife test." Come on, are we the only two husbands in awe of our gentle wives?
Hey, Outlaws: do you run your equipment formats past your own spouses?

Jay

Top
#34651 - 01/26/04 02:39 PM Re: LFM-1 Design Considerations
Scott Offline
Desperado

Registered: 01/07/10
Posts: 673
Of course!

Top
#34652 - 01/26/04 08:46 PM Re: LFM-1 Design Considerations
harp795 Offline
Gunslinger

Registered: 03/04/02
Posts: 104
Loc: Louisville, KY
Scott,

Any data on changes to output and frequency response if one or both of the ports are plugged? It sounds resonable that by plugging one or both of the ports you might gain some tightness at the expense of output and low frequency rolloff.
_________________________
"A smooth sea never made a skillful mariner"

Top
#34653 - 01/27/04 11:04 PM Re: LFM-1 Design Considerations
bossobass Offline
Desperado

Registered: 08/19/02
Posts: 430
Loc: charlotte, nc usa
As the archives will attest to, I've always said that Outlaw Audio 'gets' bass management and low freqs better than most any other audio hardware company.

I haven't seen/heard the LFM-1 yet, but I'm sure that it's a winner, and I certainly look forward to it's success and positive reviews.

For those of you who are already owners and may feel any reluctance to report the details of your setups and results in using the LFM-1, for whatever reasons, please do post your findings.

I NEVER tire of posts that have to do with quality low freq reproduction, especially now that they might include a powered sub that has the Outlaw Brand.

It goes without saying, nevertheless, Congrats to Outlaw for releasing another fine value/performance MC audio product.
_________________________
"Time wounds all heels." John Lennon

Top
#34654 - 12/08/04 01:29 AM Re: LFM-1 Design Considerations
DMF Offline
Gunslinger

Registered: 11/11/03
Posts: 37
Loc: Atlantis
Excellent info. I was reading a couple of interviews with Dr. Hsu today (pre-LFM-1) and he spent quite a bit of time in one discussing his engineering as the intelligent selection of compromises. What he did differently from other companies. One can certainly see some of his philosophy in the LFM-1. And one can see some well-reasoned departures in the LFM-1 from what he has done in his own products.

A question that might elucidate a non-obvious design choice: I haven't taken my LFM-1s apart, but from the exterior shape and another clue, it appears that the main casing is a cast resin material? One reviewer referred to the "MDF cabinet" but I'll bet it's not. Or may be MDF cast in resin. What is the main casing material and why was it chosen?
_________________________
Don't let your meat loaf.

Top

Who's Online
0 registered (), 104 Guests and 3 Spiders online.
Key: Admin, Global Mod, Mod
Newest Members
Hedoboy, naowro, BeBop, workarounder, robpar
8705 Registered Users
Top Posters (30 Days)
Forum Stats
8,705 Registered Members
88 Forums
11,326 Topics
98,691 Posts

Most users ever online: 476 @ 12/28/22 08:54 PM