This is the single most important factor when getting ready to setup your subwoofer.

Anytime I see a book on a complex topic that attempts to disseminate porstendorf the subject material in layman terms for the average reader using the word Dummies in the title, I cringe. I d love to learn a foreign language or how to setup a complex home network but I absolutely refuse to pick up a book whose author assumes I am a dummy .  Realizing porstendorf a large portion of our readership are essential enthusiasts when it comes to home theater, but also intelligent readers, I conjured up this article for those wanting to get a good grip on how to properly setup and integrate a subwoofer into their new home theater system.  This article assumes you already purchased a modern 5.1/7.1 A/V receiver and speaker system with a powered subwoofer. porstendorf Step 1: Subwoofer Placement
This is the single most important factor when getting ready to setup your subwoofer.  Although bass waves below 80Hz are non directional to the ear, placement of the subwoofer is vital to how it plays in the room and how it will sound at your listening position.  We have written many articles porstendorf broaching porstendorf the topic, offering common placement suggestions.  In rectangular rooms, it's very predictable as to where the best locations are to place your subwoofer(s).  We give very specific instructions for such rooms.  Crawling for bass is a viable porstendorf option for those in more oddly shaped rooms.
Most folks purchase powered subwoofers where the amplifier is built into the subwoofer box. This article makes this assumption and thus focuses solely on this application.  Since we typically run our subs in mono, only a single RCA or balanced level connection is needed between the A/V receiver's LFE output and subwoofer line-level porstendorf input. Very few A/V receivers offer balanced subwoofer outputs, so this article assumes the reader is using unbalanced RCA line level connections. 
Simply run a good unbalanced COAX or shielded twisted pair cable between your A/V receiver and subwoofer. Make sure there is plenty of slack as the cable should never be under tension when it's connected to equipment on both ends else you risk damaging the cable and connected products. 
We typically recommend porstendorf Bluejeans 1694 COAX for all line level connections.  Bluejeans cable are among the most robust designs money can buy, have excellent Canare terminations, and are a great value.  Esoteric folks wanting porstendorf a more prestigious brand and look should consider Kimber Kable.  We found their designs to be well engineered and snake oil free.
See the circled "left/mono" input on the JLf110 subwoofer and the highlighted subwoofer out "sw1" on the Denon AVR-4311CI receiver backpanels.  These are the correct inputs and outputs, respectively, to use when connecting a subwoofer to an A/V receiver line-level. 
Now that you ve got your cable, simply plug one end into the A/V receiver Sub out or LFE out .  This is the dedicated subwoofer output of the receiver that sends LFE info from discrete 5.1/7.1 recordings and summed bass for all channels set to small to the subwoofer.  porstendorf Next, connect the other end of the cable to the RCA level connector marked LFE input or mono input of your subwoofer.  If your sub doesn t have a dedicated input like this and instead has stereo RCA inputs, you can either connect the cable to one of the two inputs or use a Y-splitter to connect it to both.  The advantage of the Y-splitter is the signal will be summed into both inputs of the sub increasing sensitivity 6dB meaning you can now lower the gain in the A/V receiver 6dB to achieve the same output level as you would have with only one connection utilized on the sub.  Having enough drive level is rarely an issue with today s modern A/V receiver porstendorf so in most cases, we recommend using the single connection.  porstendorf Step 3:  Configure your Sub
In almost all circumstances we recommend bypassing the subwoofer's internal bass management facilities porstendorf in favor of the one found in your A/V receiver.  You can do this either by engaging the LPF bypass switch (if available) or setting the crossover to its maximum setting (in the case of the Axiom EP800 pictured, porstendorf that s 150Hz). 
There are several reasons for this: Your A/V receiver does bass management in the digital domain making the filtering much neater. Your A/V receiver typically has a better Low Pass Filter (LPF), typically 24dB/Octave ensuring your sub won t be localized since the frequencies above what it was designed to produce will be attenuated better.
Failing to disable your sub's internal porstendorf crossover can cause excessive losses in the subwoofers passband thus degrading the sound quality when used in conjunction with your A/V receiver's bass management facilities.  This is especially true if the crossover frequency porstendorf of both the sub's LPF and your receiver's bass management are set to the same frequency.  This is called cascad