I use an Outlaw ICBM to integrate and operate two powered subwoofers in my system in a stereo configuration. The ICBM is wired between the 950 and the amplifier in order to provide bass management for any source used, with or without processing, by the 950. I configure the 950 for "large" speakers everywhere, letting the ICBM handle all the crossover work. Each sub has its own input level adjustment. The subs are slightly elevated from the floor and placed almost directly underneath the left and right speakers. I have a relatively small room, so the fronts and subs are near corners, about one foot from the side wall and three feet from the front wall. I initially set up this way:

- I setup the subwoofer phasing first.
- Per the instructions for the 950, I perform channel calibration with a SPL meter for all channels except the subwoofer. I note the settings for the front left and right. As an example, let’s say that the front left setting is “4” and the front right is “3.”
- Without changing the main volume, I go to the subwoofer channel calibration and set it to “4,” agreeing with the front left setting. At this point the subwoofer output of the 950 is providing low frequency noise.
- I unplug the front left channel input cable from the ICBM and connect the cable carrying the LF noise to the front left input of the ICBM. The ICBM sends very little of this signal to the amp for the main speakers, but directs this LF noise to the ICBM left sub output.
- I adjust the level of the left subwoofer until the SPL meter reads about two dB lower than the calibrated reading of the main speaker. I do this because I know the meter I have reads very low frequencies about two dB lower than they actually are.
- I change the ICBM cable connections so that the front right ICBM input is now receiving the LF noise from the 950. I adjust the subwoofer channel calibration to “3,” agreeing with the front right setting.
- I adjust the level of the right subwoofer until the SPL meter reads about two dB lower than the calibrated reading of the main speaker.
- I restore the cabling on the ICBM to normal.
- I turn the LFE level control knob on the ICBM to the LFE calibration position.
- I adjust the 950’s subwoofer channel calibration while watching the SPL meter, again seeking a reading about two dB below the main speaker level meter reading.
- I return the LFE level control on the ICBM to its normal position of -10dB.

This is my preliminary set up. Further minor refinement may follow based on test signals generated from DVD and/or computer software. Additionally I listen to familiar passages. For instance, if one knows what an electric bass sounds like in regard to fundamental low frequencies mixed with somewhat higher harmonics of the strings in some styles of play, listen to make sure the low fundamentals are present and strong in the right places, but such that they are in the proper ratio to the higher harmonics coming from the main speakers – not so strong as to muddy the tightness of certain electric bass or drum playing. I have found that “refinement” adjusting with only one particular musical passage ends up giving me my favorite “system tuning” for that piece, and this may not be good for another piece of music. On one piece of music, I am boosting bass, on another piece, I am lowering the sub levels. I almost always end up being the happiest overall with the preliminary settings I obtain in the first place, or just slightly less than these settings.* So my recommendation is to be very “gentle” in varying the setup “to taste” after following the steps above.

I hope this helps. It may at least be a method with which to experiment.

*The reason I usually end up working "down" from these settings, is because I suspect producers of some recent music may be pushing the very low end of their mix mildly upwards in amplitude, or using some kind of "add a lower octave" processor to get a "low end feel" when playing back on normal consumer equipment, for home or vehicle, that rolls off more significantly at the low end than on the equipment belonging to those of us who seek frequency extension beyond the directly audible. Even within one CD, such as Bare by Annie Lennox, there are cuts which sound great with my initial sub settings, and other cuts with extended low end that overpower the rest of the music when played back on my main system. If I lower the subwoofer output level on the ICBM to bring the bass on the "extended low" cuts into line, then other music ends up without sufficient low end. This part is subjective, of course, but, after all, it's the end result sought is the best listening possible ... and "best listening" involves the subjective, doesn't it?

Enjoy the journey!


[This message has been edited by bestbang4thebuck (edited February 06, 2004).]