Are the JL Fathom subs really that good....

Johnnyb53, the speaker position in a room gives the most natural midrange will almost never yield also the best bass response. Whether or not one will obtain good results by placing the subwoofers close/next to the main speakers depends entirely on the room geometry - it is certainly not a given. Having the ability to place the midrange-high frequency source in the ideal place and the bass source in its (different) ideal place is the main advantage of using a subwoofer.

Way to go guys! Very useful responses so far ... u don't know how to set up... I tweak... I measure .... patience ...

Jb8312, I have seen on your system page that you have the Verity Audio Parisfal Ovation speakers. If I am not mistaken their bass module can be placed so that the woofer fires either towards the listener of away from him (i.e. towards the back wall). Because some of the low frequencies will be reproduces by the Parisfal bass modules and also by the subwoofer, the orientation of the subwoofer with respect to the bass modules and also the placing of the three bass sources in the room is very important. Thus, your situation is not exactly the typical case.

Try to following set-up procedure:

Part One: determine decent parameters for the crossover and volume settings of the subwoofer

1) Play a double bass jazz piece. I usually make a loop using the loop function of my cd player. Most often I use the beginning of the track 3 from Norah Jones' Come Away With Me album, i.e. the first measure of the starting bass piece (3-4 seconds).

2) Than using some common sense settings for the crossover and volume settings of the subwoofer move the subwoofer around the room. You are looking for the ideal place to placed the subwoofer, i.e. the position that will give you no significant resonance or nulls at the listening position. This step is best accomplished with the help of a friend/wife.

3) Once you have found a good place for the subwoofer start playing with the volume and crossover settings for the subwoofer. Your goal is to make the double bass notes to sound all even (i.e. having the same volume) and tight (when you close you eyes you should be able to imagine that these notes are produced by the double bass cords).

Part two: determine the best place for placing the subwoofer

1) Now with the volume and crossover settings determined in Part One, move the subwoofer in your listening position.

2) Play again the same loop with the jazz walking bass and walk around the room looking/listening for the places where you get the best bass sound. Here you should look for the places with good sound when your ears are about at the same height as in your listening position. Most likely you will find more than one palce. Mark the one that is convenient for placing the subwoofer.

3) Change the phase of the subwoofer and repeat step 2.

Final step: move the subwoofer to the place (determined in the previous step) that gave you the best bass integration, and of course keep the phase setting that worked best. At this point it might still be necessary to slightly adjust the crossover and volume settings of the subwoofer but only slightly.

After caring out this procedure, you might want to repeat it with the bass cabinets of your speakers reversed. You never know, you might get even better results.

I have a REL Stentor 3 subwoofer and I have used this procedure successfully a few times already. This "procedure" is a bit of a hybrid between what REL recommends and what I have read here and on other forums. I "come up" with it while looking for bass in my new room. I ended up with the REL somewhere between the two speakers and I get much better bass integration and volume than when placing the subwoofer in the corner as recommended by REL.

Good luck and keep us posted!
Paul

Irv, I would say that most often integration problems between the main speakers and subwoofers are not caused by the fact that the two are not time aligned. For example, if we place a subwoofer between the speakers and then we move it say 2 meter away from the plane of the two speakers, then at the listening position we will have a time delay of approximately 6 milliseconds between the frequencies emitted by the woofer and by the speakers. As far as I know, most experiments show that the brain considers all frequencies detected within a 50 milliseconds window as par of the same direct sound, i.e. it will detect no echo (repetition of the same sound) for such small intervals. Consequently, I would that this is a second order effect.

On the other hand, destructive and constructive interference (which creates bass nulls and/or significantly reinforce some specific frequencies) cause much more significant problems. Since this depends entirely on the room dimensions and position of the speakers and subwoofer(s) in the room, I would say this is by far the most important complication one faces when trying to integrated a subwoofer into a stereo system.

Regarding two subwoofers vs. one subwoofers issue, two subwoofers yield a more even response in the room (i.e. less null or reinforcements). Most often one can get just as good results with only one subwoofer but this requires very careful set up (this is not two say that dialing in two subwoofer is a piece of cake - not by a long shot).

Bryon, it might be helpful to explain what you mean by transient response.

Lyngdorf systems (most probably also TACT ones) that have the room correction module do exactly what you have described under point 3 in your post. Thus, what follows is based on my experience with Lyngdorf systems.

When set up right the Lyngdorf room correction system can indeed work wonders, i.e. significantly improvs in the bass response, imaging and coherency (which is related to the transient response you were talking about) of a system. However, unless one goes for the top of the line Steinway Lyngdorf system this often comes at a price, i.e. dynamics (which on one hand is what most system lack anyways, and one the other hand is the main requirement for having system that sounds life-like).

On the other hand, if set up wrong (which often happens in untreated rooms) the Lyngdorf room correction system will literally such out all life from the music. One will be left with a good bass response, a good transient response, good stereo image but crappy lifeless sound...

I would rather opt for speaker designs that attempt to time align the drivers and use a subwoofer that is cross-overed as low as possible, e.g. a REL. Of course, I am just a hobbyist and my opinion is based on my experiences so far :).